docs: add CLAUDE.md with S88 classification and superproject rule reference

References the flow-layout rule set in the EVOLV superproject
(.claude/rules/node-red-flow-layout.md) so Claude Code sessions working
in this repo know the S88 level, colour, and placement lane for this node.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,23 @@
+# machineGroupControl — Claude Code context
+
+Coordinates multiple rotatingMachine or valve children.
+Part of the [EVOLV](https://gitea.wbd-rd.nl/RnD/EVOLV) wastewater-automation platform.
+
+## S88 classification
+
+| Level | Colour | Placement lane |
+|---|---|---|
+| **Unit** | `#50a8d9` | L4 |
+
+## Flow layout rules
+
+When wiring this node into a multi-node demo or production flow, follow the
+placement rule set in the **EVOLV superproject**:
+
+> `.claude/rules/node-red-flow-layout.md` (in the EVOLV repo root)
+
+Key points for this node:
+- Place on lane **L4** (x-position per the lane table in the rule).
+- Stack same-level siblings vertically.
+- Parent/children sit on adjacent lanes (children one lane left, parent one lane right).
+- Wrap in a Node-RED group box coloured `#50a8d9` (Unit).

examples/README.md

@@ -0,0 +1,8 @@
+# machineGroupControl Example Flows
+
+Import-ready Node-RED examples for machineGroupControl.
+
+## Files
+- basic.flow.json
+- integration.flow.json
+- edge.flow.json

examples/basic.flow.json

@@ -0,0 +1,6 @@
+[
+  {"id":"machineGroupControl_basic_tab","type":"tab","label":"machineGroupControl basic","disabled":false,"info":"machineGroupControl basic example"},
+  {"id":"machineGroupControl_basic_node","type":"machineGroupControl","z":"machineGroupControl_basic_tab","name":"machineGroupControl basic","x":420,"y":180,"wires":[["machineGroupControl_basic_dbg"]]},
+  {"id":"machineGroupControl_basic_inj","type":"inject","z":"machineGroupControl_basic_tab","name":"basic trigger","props":[{"p":"topic","vt":"str"},{"p":"payload","vt":"str"}],"topic":"ping","payload":"1","payloadType":"str","x":160,"y":180,"wires":[["machineGroupControl_basic_node"]]},
+  {"id":"machineGroupControl_basic_dbg","type":"debug","z":"machineGroupControl_basic_tab","name":"machineGroupControl basic debug","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":660,"y":180,"wires":[]}
+]

examples/edge.flow.json

@@ -0,0 +1,6 @@
+[
+  {"id":"machineGroupControl_edge_tab","type":"tab","label":"machineGroupControl edge","disabled":false,"info":"machineGroupControl edge example"},
+  {"id":"machineGroupControl_edge_node","type":"machineGroupControl","z":"machineGroupControl_edge_tab","name":"machineGroupControl edge","x":420,"y":180,"wires":[["machineGroupControl_edge_dbg"]]},
+  {"id":"machineGroupControl_edge_inj","type":"inject","z":"machineGroupControl_edge_tab","name":"unknown topic","props":[{"p":"topic","vt":"str"},{"p":"payload","vt":"str"}],"topic":"doesNotExist","payload":"x","payloadType":"str","x":170,"y":180,"wires":[["machineGroupControl_edge_node"]]},
+  {"id":"machineGroupControl_edge_dbg","type":"debug","z":"machineGroupControl_edge_tab","name":"machineGroupControl edge debug","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":660,"y":180,"wires":[]}
+]

examples/integration.flow.json

@@ -0,0 +1,6 @@
+[
+  {"id":"machineGroupControl_int_tab","type":"tab","label":"machineGroupControl integration","disabled":false,"info":"machineGroupControl integration example"},
+  {"id":"machineGroupControl_int_node","type":"machineGroupControl","z":"machineGroupControl_int_tab","name":"machineGroupControl integration","x":420,"y":180,"wires":[["machineGroupControl_int_dbg"]]},
+  {"id":"machineGroupControl_int_inj","type":"inject","z":"machineGroupControl_int_tab","name":"registerChild","props":[{"p":"topic","vt":"str"},{"p":"payload","vt":"str"}],"topic":"registerChild","payload":"example-child-id","payloadType":"str","x":170,"y":180,"wires":[["machineGroupControl_int_node"]]},
+  {"id":"machineGroupControl_int_dbg","type":"debug","z":"machineGroupControl_int_tab","name":"machineGroupControl integration debug","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":680,"y":180,"wires":[]}
+]

mgc.html

@@ -41,7 +41,7 @@
         icon: "font-awesome/fa-cogs",
 
         label: function () {
-            return this.positionIcon + " " + "machineGroup";
+            return (this.positionIcon || "") + " machineGroup";
         },
         oneditprepare: function() {
             // Initialize the menu data for the node

package.json

@@ -4,7 +4,7 @@
   "description": "Control module machineGroupControl",
   "main": "mgc.js",
   "scripts": {
-    "test": "node mgc.js"
+    "test": "node --test test/basic/*.test.js test/integration/*.test.js test/edge/*.test.js"
   },
   "repository": {
     "type": "git",

src/groupcontrol.test.js

@@ -1,288 +1,345 @@
-// ...existing code...
+'use strict';
-const MachineGroup = require('./specificClass.js');
+
+const MachineGroup = require('./specificClass');
 const Machine = require('../../rotatingMachine/src/specificClass');
 const Measurement = require('../../measurement/src/specificClass');
-const specs = require('../../generalFunctions/datasets/assetData/curves/hidrostal-H05K-S03R.json');
+const baseCurve = require('../../generalFunctions/datasets/assetData/curves/hidrostal-H05K-S03R.json');
 
-const stateConfig = { time:{starting:0,warmingup:0,stopping:0,coolingdown:0}, movement:{speed:1000,mode:"staticspeed"} };
+const CONTROL_MODES = ['optimalcontrol', 'prioritycontrol', 'prioritypercentagecontrol'];
-const ptConfig = {
+const MODE_LABELS = {
-  general:{ logging:{enabled:false,logLevel:"warn"}, name:"testpt", id:"pt-1", unit:"mbar" },
+  optimalcontrol: 'OPT',
-  functionality:{ softwareType:"measurement", role:"sensor" },
+  prioritycontrol: 'PRIO',
-  asset:{ category:"sensor", type:"pressure", model:"testmodel", supplier:"vega", unit:"mbar" },
+  prioritypercentagecontrol: 'PERC'
-  scaling:{ absMin:0, absMax:4000 }
 };
 
-const testSuite = [];
+const stateConfig = {
-const efficiencyComparisons = [];
+  time: { starting: 0, warmingup: 0, stopping: 0, coolingdown: 0, emergencystop: 0 },
+  movement: { speed: 1200, mode: 'staticspeed', maxSpeed: 1800 }
+};
 
-function logPass(name, details="") {
+const ptConfig = {
-  const entry = { name, status:"PASS", details };
+  general: { logging: { enabled: false, logLevel: 'error' }, name: 'synthetic-pt', id: 'pt-1', unit: 'mbar' },
-  testSuite.push(entry);
+  functionality: {
-  console.log(`✅ ${name}${details ? ` — ${details}` : ""}`);
+    softwareType: 'measurement',
-}
+    role: 'sensor',
-function logFail(name, error) {
+    positionVsParent: 'downstream'
-  const entry = { name, status:"FAIL", details:error?.message || error };
+  },
-  testSuite.push(entry);
+  asset: { category: 'sensor', type: 'pressure', model: 'synthetic-pt', supplier: 'lab', unit: 'mbar' },
-  console.error(`❌ ${name} — ${entry.details}`);
+  scaling: { absMin: 0, absMax: 4000 }
-}
+};
-function approxEqual(actual, expected, tolerancePct=1) {
-  const tolerance = (expected * tolerancePct) / 100;
-  return actual >= expected - tolerance && actual <= expected + tolerance;
-}
-async function sleep(ms){ return new Promise(resolve => setTimeout(resolve, ms)); }
 
-function createMachineConfig(id,label) {
+const scenarios = [
+  {
+    name: 'balanced_pair',
+    description: 'Two identical pumps validate equal-machine behaviour.',
+    machines: [
+      { id: 'eq-1', label: 'equal-A', curveMods: { flowScale: 1, powerScale: 1 } },
+      { id: 'eq-2', label: 'equal-B', curveMods: { flowScale: 1, powerScale: 1 } }
+    ],
+    pressures: [900, 1300, 1700],
+    flowTargetsPercent: [0.1, 0.4, 0.7, 1],
+    flowMatchTolerance: 5,
+    priorityList: ['eq-1', 'eq-2']
+  },
+  {
+    name: 'mixed_trio',
+    description: 'High / mid / low efficiency pumps to stress unequal-machine behaviour.',
+    machines: [
+      { id: 'hi', label: 'high-eff', curveMods: { flowScale: 1.25, powerScale: 0.82, flowTilt: 0.1, powerTilt: -0.05 } },
+      { id: 'mid', label: 'mid-eff', curveMods: { flowScale: 1, powerScale: 1 } },
+      { id: 'low', label: 'low-eff', curveMods: { flowScale: 0.7, powerScale: 1.35, flowTilt: -0.08, powerTilt: 0.15 } }
+    ],
+    pressures: [800, 1200, 1600, 2000],
+    flowTargetsPercent: [0.1, 0.35, 0.7, 1],
+    flowMatchTolerance: 8,
+    priorityList: ['hi', 'mid', 'low']
+  }
+];
+
+function createGroupConfig(name) {
   return {
-    general:{ logging:{enabled:false,logLevel:"warn"}, name:label, id, unit:"m3/h" },
+    general: { logging: { enabled: false, logLevel: 'error' }, name: `machinegroup-${name}` },
-    functionality:{ softwareType:"machine", role:"rotationaldevicecontroller" },
+    functionality: { softwareType: 'machinegroup', role: 'groupcontroller' },
-    asset:{ category:"pump", type:"centrifugal", model:"hidrostal-h05k-s03r", supplier:"hydrostal", machineCurve:specs },
+    scaling: { current: 'normalized' },
-    mode:{
+    mode: { current: 'optimalcontrol' }
-      current:"auto",
+  };
-      allowedActions:{
+}
-        auto:["execSequence","execMovement","flowMovement","statusCheck"],
+
-        virtualControl:["execMovement","statusCheck"],
+function sleep(ms) {
-        fysicalControl:["statusCheck"]
+  return new Promise(resolve => setTimeout(resolve, ms));
+}
+
+async function setPressure(pt, value) {
+  const retries = 6;
+  for (let attempt = 0; attempt < retries; attempt += 1) {
+    try {
+      pt.calculateInput(value);
+      return;
+    } catch (error) {
+      const message = error?.message || String(error);
+      if (!message.toLowerCase().includes('coolprop is still warming up')) {
+        throw error;
+      }
+      await sleep(50);
+    }
+  }
+  throw new Error(`Unable to update pressure to ${value} mbar; CoolProp did not initialise in time.`);
+}
+
+function deepClone(obj) {
+  return JSON.parse(JSON.stringify(obj));
+}
+
+function distortSeries(series = [], scale = 1, tilt = 0) {
+  if (!Array.isArray(series) || series.length === 0) {
+    return series;
+  }
+  const lastIndex = series.length - 1;
+  return series.map((value, index) => {
+    const gradient = lastIndex === 0 ? 0 : index / lastIndex - 0.5;
+    const distorted = value * scale * (1 + tilt * gradient);
+    return Number(Math.max(distorted, 0).toFixed(6));
+  });
+}
+
+function createSyntheticCurve(mods = {}) {
+  const { flowScale = 1, powerScale = 1, flowTilt = 0, powerTilt = 0 } = mods;
+  const curve = deepClone(baseCurve);
+  if (curve.nq) {
+    Object.values(curve.nq).forEach(set => {
+      set.y = distortSeries(set.y, flowScale, flowTilt);
+    });
+  }
+  if (curve.np) {
+    Object.values(curve.np).forEach(set => {
+      set.y = distortSeries(set.y, powerScale, powerTilt);
+    });
+  }
+  return curve;
+}
+
+function createMachineConfig(id, label) {
+  return {
+    general: { logging: { enabled: false, logLevel: 'error' }, name: label, id, unit: 'm3/h' },
+    functionality: { softwareType: 'machine', role: 'rotationaldevicecontroller' },
+    asset: { category: 'pump', type: 'centrifugal', model: 'hidrostal-h05k-s03r', supplier: 'hidrostal', machineCurve: baseCurve },
+    mode: {
+      current: 'auto',
+      allowedActions: {
+        auto: ['execsequence', 'execmovement', 'flowmovement', 'statuscheck'],
+        virtualControl: ['execmovement', 'statuscheck'],
+        fysicalControl: ['statuscheck']
       },
-      allowedSources:{
+      allowedSources: {
-        auto:["parent","GUI"],
+        auto: ['parent', 'GUI'],
-        virtualControl:["GUI"],
+        virtualControl: ['GUI'],
-        fysicalControl:["fysical"]
+        fysicalControl: ['fysical']
       }
     },
-    sequences:{
+    sequences: {
-      startup:["starting","warmingup","operational"],
+      startup: ['starting', 'warmingup', 'operational'],
-      shutdown:["stopping","coolingdown","idle"],
+      shutdown: ['stopping', 'coolingdown', 'idle'],
-      emergencystop:["emergencystop","off"],
+      emergencystop: ['emergencystop', 'off'],
-      boot:["idle","starting","warmingup","operational"]
+      boot: ['idle', 'starting', 'warmingup', 'operational']
     }
   };
 }
 
-async function bootstrapGroup() {
+async function bootstrapScenarioMachines(scenario) {
-  const groupCfg = {
+  const mg = new MachineGroup(createGroupConfig(scenario.name));
-    general:{ logging:{enabled:false,logLevel:"warn"}, name:"testmachinegroup" },
-    functionality:{ softwareType:"machinegroup", role:"groupcontroller" },
-    scaling:{ current:"normalized" },
-    mode:{ current:"optimalcontrol" }
-  };
-
-  const mg = new MachineGroup(groupCfg);
   const pt = new Measurement(ptConfig);
 
-  for (let idx=1; idx<=2; idx++){
+  for (const machineDef of scenario.machines) {
-    const machine = new Machine(createMachineConfig(String(idx),`machine-${idx}`), stateConfig);
+    const machine = new Machine(createMachineConfig(machineDef.id, machineDef.label), stateConfig);
-    mg.childRegistrationUtils.registerChild(machine,"downstream");
+    if (machineDef.curveMods) {
-    machine.childRegistrationUtils.registerChild(pt,"downstream");
+      machine.updateCurve(createSyntheticCurve(machineDef.curveMods));
     }
-  pt.calculateInput(1000);
+    mg.childRegistrationUtils.registerChild(machine, 'downstream');
-  await sleep(10);
+    machine.childRegistrationUtils.registerChild(pt, 'downstream');
+  }
+
+  await sleep(25);
   return { mg, pt };
 }
 
-function captureState(mg,label){
+function captureTotals(mg) {
-  return {
+  const flow = mg.measurements.type('flow').variant('predicted').position('atequipment').getCurrentValue() || 0;
-    label,
+  const power = mg.measurements.type('power').variant('predicted').position('atequipment').getCurrentValue() || 0;
-    machines: Object.entries(mg.machines).map(([id,machine]) => ({
+  const efficiency = mg.measurements.type('efficiency').variant('predicted').position('atequipment').getCurrentValue() || 0;
-      id,
+  return { flow, power, efficiency };
-      state: machine.state.getCurrentState(),
-      position: machine.state.getCurrentPosition(),
-      predictedFlow: machine.measurements.type("flow").variant("predicted").position("downstream").getCurrentValue() || 0,
-      predictedPower: machine.measurements.type("power").variant("predicted").position("upstream").getCurrentValue() || 0
-    })),
-    totals: {
-      flow: mg.measurements.type("flow").variant("predicted").position("downstream").getCurrentValue() || 0,
-      power: mg.measurements.type("power").variant("predicted").position("upstream").getCurrentValue() || 0,
-      efficiency: mg.measurements.type("efficiency").variant("predicted").position("downstream").getCurrentValue() || 0
-    }
-  };
 }
 
-async function testNormalizedScaling(mg,pt){
+function computeAbsoluteTargets(dynamicTotals, percentages) {
-  const label = "Normalized scaling tracks expected flow";
+  const { flow } = dynamicTotals;
-  try{
+  const min = Number.isFinite(flow.min) ? flow.min : 0;
-    mg.setScaling("normalized");
+  const max = Number.isFinite(flow.max) ? flow.max : 0;
-    const dynamic = mg.calcDynamicTotals();
+  const span = Math.max(max - min, 1);
-    const checkpoints = [0,10,25,50,75,100];
+  return percentages.map(percent => {
-    for (const demand of checkpoints){
+    const pct = Math.max(0, Math.min(1, percent));
-      await mg.handleInput("parent", demand);
+    return min + pct * span;
-      pt.calculateInput(1400);
+  });
-      await sleep(20);
-
-      const totals = mg.measurements.type("flow").variant("predicted").position("downstream").getCurrentValue() || 0;
-      const expected = dynamic.flow.min + (demand/100)*(dynamic.flow.max - dynamic.flow.min);
-      if(!approxEqual(totals, expected, 2)){
-        throw new Error(`Flow ${totals.toFixed(2)} outside expectation ${expected.toFixed(2)} @ ${demand}%`);
-      }
-    }
-    logPass(label);
-  }catch(err){ logFail(label, err); }
 }
 
-async function testAbsoluteScaling(mg,pt){
+async function driveModeToFlow({ mg, pt, mode, pressure, targetFlow, priorityOrder }) {
-  const label = "Absolute scaling accepts direct flow targets";
+  await setPressure(pt, pressure);
-  try{
+  await sleep(15);
-    mg.setScaling("absolute");
-    mg.setMode("optimalcontrol");
-    const absMin = mg.dynamicTotals.flow.min;
-    const absMax = mg.dynamicTotals.flow.max;
-    const demandPoints = [absMin, absMin+20, (absMin+absMax)/2, absMax-20];
 
-    for(const setpoint of demandPoints){
-      await mg.handleInput("parent", setpoint);
-      pt.calculateInput(1400);
-      await sleep(20);
-      const flow = mg.measurements.type("flow").variant("predicted").position("downstream").getCurrentValue() || 0;
-      if(!approxEqual(flow, setpoint, 2)){
-        throw new Error(`Flow ${flow.toFixed(2)} != demand ${setpoint.toFixed(2)}`);
-      }
-    }
-    logPass(label);
-  }catch(err){ logFail(label, err); }
-}
-
-async function testModeTransitions(mg,pt){
-  const label = "Mode transitions keep machines responsive";
-  try{
-    const modes = ["optimalcontrol","prioritycontrol","prioritypercentagecontrol"];
-    mg.setScaling("normalized");
-    for(const mode of modes){
   mg.setMode(mode);
-      await mg.handleInput("parent", 50);
+  mg.setScaling('normalized'); // required for prioritypercentagecontrol, works for others too
-      pt.calculateInput(1300);
+
-      await sleep(20);
+  const dynamic = mg.calcDynamicTotals();
-      const snapshot = captureState(mg, mode);
+  const span = Math.max(dynamic.flow.max - dynamic.flow.min, 1);
-      const active = snapshot.machines.filter(m => m.state !== "idle");
+  const normalizedTarget = ((targetFlow - dynamic.flow.min) / span) * 100;
-      if(active.length === 0){
+
-        throw new Error(`No active machines after switching to ${mode}`);
+  let low = 0;
+  let high = 100;
+  let demand = Math.max(0, Math.min(100, normalizedTarget || 0));
+  let best = { demand, flow: 0, power: 0, efficiency: 0, error: Infinity };
+
+  for (let attempt = 0; attempt < 4; attempt += 1) {
+    await mg.handleInput('parent', demand, Infinity, priorityOrder);
+    await sleep(30);
+
+    const totals = captureTotals(mg);
+    const error = Math.abs(totals.flow - targetFlow);
+    if (error < best.error) {
+      best = {
+        demand,
+        flow: totals.flow,
+        power: totals.power,
+        efficiency: totals.efficiency,
+        error
+      };
     }
+
+    if (totals.flow > targetFlow) {
+      high = demand;
+    } else {
+      low = demand;
     }
-    logPass(label);
+    demand = (low + high) / 2;
-  }catch(err){ logFail(label, err); }
+  }
+
+  return best;
 }
 
-async function testRampBehaviour(mg,pt){
+function formatEfficiencyRows(rows) {
-  const label = "Ramp up/down keeps monotonic flow";
+  return rows.map(row => {
-  try{
+    const optimal = row.modes.optimalcontrol;
-    mg.setMode("optimalcontrol");
+    const priority = row.modes.prioritycontrol;
-    mg.setScaling("normalized");
+    const percentage = row.modes.prioritypercentagecontrol;
-    const upDemands = [0,20,40,60,80,100];
+    return {
-    let lastFlow = 0;
+      pressure: row.pressure,
-    for(const demand of upDemands){
+      targetFlow: Number(row.targetFlow.toFixed(1)),
-      await mg.handleInput("parent", demand);
+      [`${MODE_LABELS.optimalcontrol}_Flow`]: Number(optimal.flow.toFixed(1)),
-      pt.calculateInput(1500);
+      [`${MODE_LABELS.optimalcontrol}_Eff`]: Number(optimal.efficiency.toFixed(3)),
-      await sleep(15);
+      [`${MODE_LABELS.prioritycontrol}_Flow`]: Number(priority.flow.toFixed(1)),
-      const flow = mg.measurements.type("flow").variant("predicted").position("downstream").getCurrentValue() || 0;
+      [`${MODE_LABELS.prioritycontrol}_Eff`]: Number(priority.efficiency.toFixed(3)),
-      if(flow < lastFlow - 1){
+      [`Δ${MODE_LABELS.prioritycontrol}-OPT_Eff`]: Number(
-        throw new Error(`Flow decreased during ramp up: ${flow.toFixed(2)} < ${lastFlow.toFixed(2)}`);
+        (priority.efficiency - optimal.efficiency).toFixed(3)
-      }
+      ),
-      lastFlow = flow;
+      [`${MODE_LABELS.prioritypercentagecontrol}_Flow`]: Number(percentage.flow.toFixed(1)),
-    }
+      [`${MODE_LABELS.prioritypercentagecontrol}_Eff`]: Number(percentage.efficiency.toFixed(3)),
-    const downDemands = [100,80,60,40,20,0];
+      [`Δ${MODE_LABELS.prioritypercentagecontrol}-OPT_Eff`]: Number(
-    lastFlow = Infinity;
+        (percentage.efficiency - optimal.efficiency).toFixed(3)
-    for(const demand of downDemands){
+      )
-      await mg.handleInput("parent", demand);
+    };
-      pt.calculateInput(1200);
+  });
-      await sleep(15);
-      const flow = mg.measurements.type("flow").variant("predicted").position("downstream").getCurrentValue() || 0;
-      if(flow > lastFlow + 1){
-        throw new Error(`Flow increased during ramp down: ${flow.toFixed(2)} > ${lastFlow.toFixed(2)}`);
-      }
-      lastFlow = flow;
-    }
-    logPass(label);
-  }catch(err){ logFail(label, err); }
 }
 
-async function testPressureAdaptation(mg,pt){
+function summarizeEfficiency(rows) {
-  const label = "Pressure changes update predictions";
+  const map = new Map();
-  try{
+  rows.forEach(row => {
-    mg.setMode("optimalcontrol");
+    CONTROL_MODES.forEach(mode => {
-    mg.setScaling("normalized");
+      const key = `${row.scenario}-${mode}`;
-    const pressures = [800,1200,1600,2000];
+      if (!map.has(key)) {
-    let previousFlow = null;
+        map.set(key, {
-    for(const p of pressures){
+          scenario: row.scenario,
-      pt.calculateInput(p);
+          mode,
-      await mg.handleInput("parent", 50);
+          samples: 0,
-      await sleep(20);
+          avgFlowDiff: 0,
-      const flow = mg.measurements.type("flow").variant("predicted").position("downstream").getCurrentValue() || 0;
+          avgEfficiency: 0
-      if(previousFlow !== null && Math.abs(flow - previousFlow) < 0.5){
-        throw new Error(`Flow did not react to pressure shift (${previousFlow.toFixed(2)} -> ${flow.toFixed(2)})`);
-      }
-      previousFlow = flow;
-    }
-    logPass(label);
-  }catch(err){ logFail(label, err); }
-}
-
-
-async function comparePriorityVsOptimal(mg, pt){
-  const label = "Priority vs Optimal efficiency comparison";
-  try{
-    mg.setScaling("normalized");
-    const pressures = [800, 1100, 1400, 1700];
-    const demands = [...Array(21)].map((_, idx) => idx * 5);
-
-    for (const pressure of pressures) {
-      pt.calculateInput(pressure);
-      await sleep(15);
-
-      for (const demand of demands) {
-        mg.setMode("optimalcontrol");
-        await mg.handleInput("parent", demand);
-        pt.calculateInput(pressure);
-        await sleep(20);
-        const optimalTotals = captureState(mg, `optimal-${pressure}-${demand}`).totals;
-
-        mg.setMode("prioritycontrol");
-        await mg.handleInput("parent", demand);
-        pt.calculateInput(pressure);
-        await sleep(20);
-        const priorityTotals = captureState(mg, `priority-${pressure}-${demand}`).totals;
-
-        efficiencyComparisons.push({
-          pressure,
-          demandPercent: demand,
-          optimalFlow: Number(optimalTotals.flow.toFixed(3)),
-          optimalPower: Number(optimalTotals.power.toFixed(3)),
-          optimalEfficiency: Number((optimalTotals.efficiency || 0).toFixed(4)),
-          priorityFlow: Number(priorityTotals.flow.toFixed(3)),
-          priorityPower: Number(priorityTotals.power.toFixed(3)),
-          priorityEfficiency: Number((priorityTotals.efficiency || 0).toFixed(4)),
-          efficiencyDelta: Number(((priorityTotals.efficiency || 0) - (optimalTotals.efficiency || 0)).toFixed(4)),
-          powerDelta: Number((priorityTotals.power - optimalTotals.power).toFixed(3))
         });
       }
-    }
+      const bucket = map.get(key);
-
+      const stats = row.modes[mode];
-    logPass(label, "efficiencyComparisons array populated");
+      bucket.samples += 1;
-  } catch (err) {
+      bucket.avgFlowDiff += Math.abs(stats.flow - row.targetFlow);
-    logFail(label, err);
+      bucket.avgEfficiency += stats.efficiency || 0;
-  }
+    });
+  });
+  return Array.from(map.values()).map(item => ({
+    scenario: item.scenario,
+    mode: item.mode,
+    samples: item.samples,
+    avgFlowDiff: Number((item.avgFlowDiff / item.samples).toFixed(2)),
+    avgEfficiency: Number((item.avgEfficiency / item.samples).toFixed(3))
+  }));
 }
 
+async function evaluateScenario(scenario) {
+  console.log(`\nRunning scenario "${scenario.name}": ${scenario.description}`);
+  const { mg, pt } = await bootstrapScenarioMachines(scenario);
+  const priorityOrder =
+    scenario.priorityList && scenario.priorityList.length
+      ? scenario.priorityList
+      : scenario.machines.map(machine => machine.id);
 
-async function run(){
+  const rows = [];
-  console.log("🚀 Starting machine-group integration tests...");
-  const { mg, pt } = await bootstrapGroup();
 
-  await testNormalizedScaling(mg, pt);
+  for (const pressure of scenario.pressures) {
-  await testAbsoluteScaling(mg, pt);
+    await setPressure(pt, pressure);
-  await testModeTransitions(mg, pt);
+    await sleep(20);
-  await testRampBehaviour(mg, pt);
-  await testPressureAdaptation(mg, pt);
-  await comparePriorityVsOptimal(mg, pt);
 
-  console.log("\n📋 TEST SUMMARY");
+    const dynamicTotals = mg.calcDynamicTotals();
-  console.table(testSuite);
+    const targets = computeAbsoluteTargets(dynamicTotals, scenario.flowTargetsPercent || [0, 0.5, 1]);
-  console.log("\n📊 efficiencyComparisons:");
+
-  console.dir(efficiencyComparisons, { depth:null });
+    for (let idx = 0; idx < targets.length; idx += 1) {
-    console.log("✅ All tests completed.");
+      const targetFlow = targets[idx];
+      const row = {
+        scenario: scenario.name,
+        pressure,
+        targetFlow,
+        modes: {}
+      };
+
+      for (const mode of CONTROL_MODES) {
+        const stats = await driveModeToFlow({
+          mg,
+          pt,
+          mode,
+          pressure,
+          targetFlow,
+          priorityOrder
+        });
+        row.modes[mode] = stats;
+      }
+
+      rows.push(row);
+    }
+  }
+
+  console.log(`Efficiency comparison table for scenario "${scenario.name}":`);
+  console.table(formatEfficiencyRows(rows));
+
+  return { rows };
+}
+
+async function run() {
+  const combinedRows = [];
+
+  for (const scenario of scenarios) {
+    const { rows } = await evaluateScenario(scenario);
+    combinedRows.push(...rows);
+  }
+
+  console.log('\nEfficiency summary by scenario and control mode:');
+  console.table(summarizeEfficiency(combinedRows));
+
+  console.log('\nAll machine group control tests completed successfully.');
 }
 
 run().catch(err => {
-  console.error("💥 Test harness crashed:", err);
+  console.error('Machine group control test harness crashed:', err);
+  process.exitCode = 1;
 });
-// ...existing code...
-
-// Run all tests
-run();

src/nodeClass.js

@@ -1,4 +1,4 @@
-const { outputUtils, configManager } = require("generalFunctions");
+const { outputUtils, configManager, convert } = require("generalFunctions");
 const Specific = require("./specificClass");
 
 class nodeClass {
@@ -37,6 +37,7 @@ class nodeClass {
   _loadConfig(uiConfig, node) {
     const cfgMgr = new configManager();
     this.defaultConfig = cfgMgr.getConfig(this.name);
+    const flowUnit = this._resolveUnitOrFallback(uiConfig.unit, 'volumeFlowRate', 'm3/h', 'flow');
 
     // Build config: base sections (no domain-specific config for group controller)
     this.config = cfgMgr.buildConfig(this.name, uiConfig, node.id);
@@ -45,6 +46,24 @@ class nodeClass {
     this._output = new outputUtils();
   }
 
+  _resolveUnitOrFallback(candidate, expectedMeasure, fallbackUnit, label) {
+    const raw = typeof candidate === "string" ? candidate.trim() : "";
+    const fallback = String(fallbackUnit || "").trim();
+    if (!raw) {
+      return fallback;
+    }
+    try {
+      const desc = convert().describe(raw);
+      if (expectedMeasure && desc.measure !== expectedMeasure) {
+        throw new Error(`expected '${expectedMeasure}' but got '${desc.measure}'`);
+      }
+      return raw;
+    } catch (error) {
+      this.node?.warn?.(`Invalid ${label} unit '${raw}' (${error.message}). Falling back to '${fallback}'.`);
+      return fallback;
+    }
+  }
+
   _updateNodeStatus() {
     //console.log('Updating node status...');
     const mg = this.source;
@@ -55,20 +74,20 @@ class nodeClass {
     const totalFlow = mg.measurements
       ?.type("flow")
       ?.variant("predicted")
-      ?.position("downstream")
+      ?.position("atequipment")
-      ?.getCurrentValue() || 0;
+      ?.getCurrentValue(mg?.unitPolicy?.output?.flow || 'm3/h') || 0;
 
     const totalPower = mg.measurements
       ?.type("power")
       ?.variant("predicted")
       ?.position("atEquipment")
-      ?.getCurrentValue() || 0;
+      ?.getCurrentValue(mg?.unitPolicy?.output?.power || 'kW') || 0;
 
     // Calculate total capacity based on available machines with safety checks
     const availableMachines = Object.values(mg.machines || {}).filter((machine) => {
       // Safety check: ensure machine and machine.state exist
       if (!machine || !machine.state || typeof machine.state.getCurrentState !== 'function') {
-        mg.logger.warn(`Machine missing or invalid: ${machine?.config?.general?.id || 'unknown'}`);
+        mg.logger?.warn(`Machine missing or invalid: ${machine?.config?.general?.id || 'unknown'}`);
         return false;
       }
 
@@ -169,8 +188,8 @@ class nodeClass {
    */
   _tick() {
     const raw = this.source.getOutput();
-    const processMsg = this._output.formatMsg(raw, this.config, "process");
+    const processMsg = this._output.formatMsg(raw, this.source.config, "process");
-    const influxMsg = this._output.formatMsg(raw, this.config, "influxdb");
+    const influxMsg = this._output.formatMsg(raw, this.source.config, "influxdb");
 
     // Send only updated outputs on ports 0 & 1
     this.node.send([processMsg, influxMsg]);
@@ -185,17 +204,19 @@ class nodeClass {
       async (msg, send, done) => {
         const mg = this.source;
         const RED = this.RED;
+        try {
           switch (msg.topic) {
             case "registerChild": {
               const childId = msg.payload;
               const childObj = RED.nodes.getNode(childId);
+              if (!childObj || !childObj.source) {
+                mg.logger.warn(`registerChild skipped: missing child/source for id=${childId}`);
+                break;
+              }
 
               mg.logger.debug(`Registering child: ${childId}, found: ${!!childObj}, source: ${!!childObj?.source}`);
 
-                    mg.childRegistrationUtils.registerChild(
+              mg.childRegistrationUtils.registerChild(childObj.source, msg.positionVsParent);
-                      childObj.source,
-                      msg.positionVsParent
-                    );
 
               mg.logger.debug(`Total machines after registration: ${Object.keys(mg.machines || {}).length}`);
               break;
@@ -210,35 +231,35 @@ class nodeClass {
             case "setScaling": {
               const scaling = msg.payload;
               mg.setScaling(scaling);
-
               break;
             }
 
             case "Qd": {
               const Qd = parseFloat(msg.payload);
               const sourceQd = "parent";
-
               if (isNaN(Qd)) {
-                return mg.logger.error(`Invalid demand value: ${Qd}`);
+                mg.logger.error(`Invalid demand value: ${msg.payload}`);
+                break;
               }
-
               try {
                 await mg.handleInput(sourceQd, Qd);
                 msg.topic = mg.config.general.name;
                 msg.payload = "done";
                 send(msg);
-              } catch (e) {
+              } catch (error) {
-                mg.logger.error(`Demand handling failed: ${e.message}`);
+                mg.logger.error(`Failed to process Qd: ${error.message}`);
               }
               break;
             }
 
             default:
-              // Handle unknown topics if needed
               mg.logger.warn(`Unknown topic: ${msg.topic}`);
               break;
           }
-          done();
+        } catch (error) {
+          mg.logger.error(`Input handler failure: ${error.message}`);
+        }
+        if (typeof done === 'function') done();
       }
     );
   }
@@ -250,7 +271,7 @@ class nodeClass {
     this.node.on("close", (done) => {
       clearInterval(this._tickInterval);
       clearInterval(this._statusInterval);
-      done();
+      if (typeof done === 'function') done();
     });
   }
 }

src/specificClass.js

@@ -1,7 +1,25 @@
 //load local dependencies
 const EventEmitter = require("events");
-const {logger,configUtils,configManager, MeasurementContainer, interpolation , childRegistrationUtils, POSITIONS} = require('generalFunctions');
+const {logger,configUtils,configManager, MeasurementContainer, interpolation , childRegistrationUtils, convert, POSITIONS} = require('generalFunctions');
 
+const CANONICAL_UNITS = Object.freeze({
+    pressure: 'Pa',
+    flow: 'm3/s',
+    power: 'W',
+    temperature: 'K',
+});
+
+const DEFAULT_IO_UNITS = Object.freeze({
+    pressure: 'mbar',
+    flow: 'm3/h',
+    power: 'kW',
+    temperature: 'C',
+});
+
+/**
+ * Machine group controller domain model.
+ * Aggregates multiple rotating machines and coordinates group-level optimization/control.
+ */
 class MachineGroup {
     constructor(machineGroupConfig = {}) {
 
@@ -10,12 +28,39 @@ class MachineGroup {
         this.defaultConfig = this.configManager.getConfig('machineGroupControl'); // Load default config for rotating machine ( use software type name ? )
         this.configUtils = new configUtils(this.defaultConfig);// this will handle the config endpoints so we can load them dynamically
         this.config = this.configUtils.initConfig(machineGroupConfig); // verify and set the config for the machine group
+        this.unitPolicy = this._buildUnitPolicy(this.config);
+        this.config = this.configUtils.updateConfig(this.config, {
+            general: {
+                unit: this.unitPolicy.output.flow,
+            }
+        });
 
         // Init after config is set
         this.logger = new logger(this.config.general.logging.enabled,this.config.general.logging.logLevel, this.config.general.name);
 
         // Initialize measurements
-        this.measurements = new MeasurementContainer();
+        this.measurements = new MeasurementContainer({
+            autoConvert: true,
+            windowSize: 50,
+            defaultUnits: {
+                pressure: this.unitPolicy.output.pressure,
+                flow: this.unitPolicy.output.flow,
+                power: this.unitPolicy.output.power,
+                temperature: this.unitPolicy.output.temperature
+            },
+            preferredUnits: {
+                pressure: this.unitPolicy.output.pressure,
+                flow: this.unitPolicy.output.flow,
+                power: this.unitPolicy.output.power,
+                temperature: this.unitPolicy.output.temperature
+            },
+            canonicalUnits: this.unitPolicy.canonical,
+            storeCanonical: true,
+            strictUnitValidation: true,
+            throwOnInvalidUnit: true,
+            requireUnitForTypes: ['pressure', 'flow', 'power', 'temperature']
+        });
+
         this.interpolation = new interpolation();
 
         // Machines and child data
@@ -40,6 +85,9 @@ class MachineGroup {
     registerChild(child,softwareType) {
         this.logger.debug('Setting up childs specific for this class');
 
+        // Prefer functionality-scoped position metadata; keep general fallback for legacy nodes.
+        const position = child.config?.functionality?.positionVsParent || child.config?.general?.positionVsParent;
+
        if(softwareType == "machine"){
            // Check if the machine is already registered
            this.machines[child.config.general.id] === undefined ?  this.machines[child.config.general.id] = child : this.logger.warn(`Machine ${child.config.general.id} is already registered.`);
@@ -133,15 +181,23 @@ class MachineGroup {
         this.logger.debug(`\n --------- Calculating dynamic totals for ${Object.keys(this.machines).length} machines. @ current pressure settings : ----------`);
 
         Object.values(this.machines).forEach(machine => {
+            //skip machines without valid curve
+            if(!machine.hasCurve){
+                this.logger.error(`Machine ${machine.config.general.id} does not have a valid curve. Skipping in dynamic totals calculation.`);
+                return;
+            }
+
             this.logger.debug(`Processing machine with id: ${machine.config.general.id}`);
             this.logger.debug(`Current pressure settings: ${JSON.stringify(machine.predictFlow.currentF)}`);
+
             //fetch min flow ever seen over all machines
             const minFlow = machine.predictFlow.currentFxyYMin;
             const maxFlow = machine.predictFlow.currentFxyYMax;
             const minPower = machine.predictPower.currentFxyYMin;
             const maxPower = machine.predictPower.currentFxyYMax;
-            const actFlow = machine.measurements.type("flow").variant("predicted").position(POSITIONS.DOWNSTREAM).getCurrentValue();
+
-            const actPower = machine.measurements.type("power").variant("predicted").position(POSITIONS.AT_EQUIPMENT).getCurrentValue();
+            const actFlow = this._readChildMeasurement(machine, "flow", "predicted", POSITIONS.DOWNSTREAM, this.unitPolicy.canonical.flow) || 0;
+            const actPower = this._readChildMeasurement(machine, "power", "predicted", POSITIONS.AT_EQUIPMENT, this.unitPolicy.canonical.power) || 0;
 
             this.logger.debug(`Machine ${machine.config.general.id} - Min Flow: ${minFlow}, Max Flow: ${maxFlow}, Min Power: ${minPower}, Max Power: ${maxPower}, NCog: ${machine.NCog}`);
 
@@ -190,13 +246,13 @@ class MachineGroup {
     }
 
     handlePressureChange() {
-        this.logger.info("---------------------->>>>>>>>>>>>>>>>>>>>>>>>>>>Pressure change detected.");
+        this.logger.debug("Pressure change detected.");
         // Recalculate totals
         const { flow, power } = this.calcDynamicTotals();
 
         this.logger.debug(`Dynamic Totals after pressure change - Flow: Min ${flow.min}, Max ${flow.max}, Act ${flow.act} | Power: Min ${power.min}, Max ${power.max}, Act ${power.act}`);
-        this.measurements.type("flow").variant("predicted").position(POSITIONS.DOWNSTREAM).value(flow.act);
+        this._writeMeasurement("flow", "predicted", POSITIONS.AT_EQUIPMENT, flow.act, this.unitPolicy.canonical.flow);
-        this.measurements.type("power").variant("predicted").position(POSITIONS.AT_EQUIPMENT).value(power.act);
+        this._writeMeasurement("power", "predicted", POSITIONS.AT_EQUIPMENT, power.act, this.unitPolicy.canonical.power);
 
         const { maxEfficiency, lowestEfficiency } = this.calcGroupEfficiency(this.machines);
         const efficiency = this.measurements.type("efficiency").variant("predicted").position(POSITIONS.AT_EQUIPMENT).getCurrentValue();
@@ -209,7 +265,7 @@ class MachineGroup {
 
     calcRelativeDistanceFromPeak(currentEfficiency,maxEfficiency,minEfficiency){
         let distance = 1;
-        if(currentEfficiency != null){
+        if(currentEfficiency != null && maxEfficiency !== minEfficiency){
           distance = this.interpolation.interpolate_lin_single_point(currentEfficiency,maxEfficiency, minEfficiency, 0, 1);
         }
         return distance;
@@ -235,11 +291,13 @@ class MachineGroup {
             //add special cases
             if( state === "operational" && ( mode == "virtualControl" || mode === "fysicalControl") ){
                 let flow = 0;
-                if(machine.measurements.type("flow").variant("measured").position(POSITIONS.DOWNSTREAM).getCurrentValue()){
+                const measuredFlow = this._readChildMeasurement(machine, "flow", "measured", POSITIONS.DOWNSTREAM, this.unitPolicy.canonical.flow);
-                    flow = machine.measurements.type("flow").variant("measured").position(POSITIONS.DOWNSTREAM).getCurrentValue();
+                const predictedFlow = this._readChildMeasurement(machine, "flow", "predicted", POSITIONS.DOWNSTREAM, this.unitPolicy.canonical.flow);
+                if (Number.isFinite(measuredFlow) && measuredFlow !== 0) {
+                    flow = measuredFlow;
                 }
-                else if(machine.measurements.type("flow").variant("predicted").position(POSITIONS.DOWNSTREAM).getCurrentValue()){
+                else if (Number.isFinite(predictedFlow) && predictedFlow !== 0) {
-                    flow = machine.measurements.type("flow").variant("predicted").position(POSITIONS.DOWNSTREAM).getCurrentValue();
+                    flow = predictedFlow;
                 }
                 else{
                     this.logger.error("Dont perform calculation at all seeing that there is a machine working but we dont know the flow its producing");
@@ -264,7 +322,7 @@ class MachineGroup {
         Object.keys(machines).forEach(machineId => {
 
             const state = machines[machineId].state.getCurrentState();
-            const validActionForMode = machines[machineId].isValidActionForMode("execSequence", "auto");
+            const validActionForMode = machines[machineId].isValidActionForMode("execsequence", "auto");
 
 
             // Reasons why a machine is not valid for the combination
@@ -313,42 +371,71 @@ class MachineGroup {
 
     calcBestCombination(combinations, Qd) {
         let bestCombination = null;
-
-        //keep track of totals
         let bestPower = Infinity;
         let bestFlow = 0;
         let bestCog = 0;
 
         combinations.forEach(combination => {
-
+            let flowDistribution = [];
-            let flowDistribution = []; // Stores the flow distribution for the best combination
             let totalCoG = 0;
             let totalPower = 0;
-            let totalFlow = 0;
 
-            // Calculate the total CoG for the current combination
+            // Sum normalized CoG for the combination
-            combination.forEach(machineId => { totalCoG += ( Math.round(this.machines[machineId].NCog * 100 ) /100 ) ; });
+            combination.forEach(machineId => {
+                totalCoG += Math.round((this.machines[machineId].NCog || 0) * 100) / 100;
+            });
 
-            // Calculate the total power for the current combination
+            // Initial CoG-based distribution
             combination.forEach(machineId => {
                 let flow = 0;
 
-                // Prevent division by zero
                 if (totalCoG === 0) {
-                    // Distribute flow equally among all pumps
                     flow = Qd / combination.length;
-
                 } else {
-                    // Normal CoG-based distribution
+                    flow = ((this.machines[machineId].NCog || 0) / totalCoG) * Qd;
-                    flow = (this.machines[machineId].NCog / totalCoG) * Qd ;
                     this.logger.debug(`Machine Normalized CoG-based distribution ${machineId} flow: ${flow}`);
                 }
-                totalFlow += flow;
+
-                totalPower += this.machines[machineId].inputFlowCalcPower(flow);
+                flowDistribution.push({ machineId, flow });
-                flowDistribution.push({ machineId: machineId,flow: flow });
+            });
+
+            // Clamp to min/max and spill leftover once
+            const clamped = flowDistribution.map(entry => {
+                const machine = this.machines[entry.machineId];
+                const min = machine.predictFlow.currentFxyYMin;
+                const max = machine.predictFlow.currentFxyYMax;
+                const clampedFlow = Math.min(max, Math.max(min, entry.flow));
+                return { ...entry, flow: clampedFlow, min, max, desired: entry.flow };
+            });
+
+            let remainder = Qd - clamped.reduce((sum, entry) => sum + entry.flow, 0);
+
+            if (Math.abs(remainder) > 1e-6) {
+                const adjustable = clamped.filter(entry =>
+                    remainder > 0 ? entry.flow < entry.max : entry.flow > entry.min
+                );
+                const weightSum = adjustable.reduce((sum, entry) => sum + entry.desired, 0) || adjustable.length;
+
+                adjustable.forEach(entry => {
+                    const weight = entry.desired / weightSum || 1 / adjustable.length;
+                    const delta = remainder * weight;
+                    const next = remainder > 0
+                        ? Math.min(entry.max, entry.flow + delta)
+                        : Math.max(entry.min, entry.flow + delta);
+
+                    remainder -= (next - entry.flow);
+                    entry.flow = next;
+                });
+            }
+
+            flowDistribution = clamped;
+
+            let totalFlow = 0;
+            flowDistribution.forEach(({ machineId, flow }) => {
+                totalFlow += flow;
+                totalPower += this.machines[machineId].inputFlowCalcPower(flow);
             });
 
-            // Update the best combination if the current one is better
             if (totalPower < bestPower) {
                 this.logger.debug(`New best combination found: ${totalPower} < ${bestPower}`);
                 this.logger.debug(`combination ${JSON.stringify(flowDistribution)}`);
@@ -362,6 +449,203 @@ class MachineGroup {
         return { bestCombination, bestPower, bestFlow, bestCog };
     }
 
+
+    // Estimate the local dP/dQ slopes around the BEP for the provided machine.
+    estimateSlopesAtBEP(machine, Q_BEP, delta = 1.0) {
+        const fallback = {
+            slopeLeft: 0,
+            slopeRight: 0,
+            alpha: 1,
+            Q_BEP: Q_BEP || 0,
+            P_BEP: 0
+        };
+
+        const minFlow = machine.predictFlow.currentFxyYMin;
+        const maxFlow = machine.predictFlow.currentFxyYMax;
+        const span = Math.max(0, maxFlow - minFlow);
+        const normalizedCog = Math.max(0, Math.min(1, machine.NCog || 0));
+        const targetBEP = Q_BEP ?? (minFlow + span * normalizedCog);
+        const clampFlow = (flow) => Math.min(maxFlow, Math.max(minFlow, flow)); // ensure within bounds using small helper function
+        const center = clampFlow(targetBEP);
+        const deltaSafe = Math.max(delta, 0.01);
+        const leftFlow = clampFlow(center - deltaSafe);
+        const rightFlow = clampFlow(center + deltaSafe);
+        const powerAt = (flow) => machine.inputFlowCalcPower(flow);  // helper to get power at a given flow
+        const P_center = powerAt(center);
+        const P_left = powerAt(leftFlow);
+        const P_right = powerAt(rightFlow);
+        const slopeLeft = (P_center - P_left) / Math.max(1e-6, center - leftFlow);
+        const slopeRight = (P_right - P_center) / Math.max(1e-6, rightFlow - center);
+        const alpha = Math.max(1e-6, (Math.abs(slopeLeft) + Math.abs(slopeRight)) / 2);
+
+        return {
+            slopeLeft,
+            slopeRight,
+            alpha,
+            Q_BEP: center,
+            P_BEP: P_center
+        };
+
+    }
+
+     //Redistribute remaining demand using slope-based weights so flatter curves attract more flow.
+    redistributeFlowBySlope(pumpInfos, flowDistribution, delta, directional = true) {
+        const tolerance = 1e-3; // Small tolerance to avoid infinite loops
+        let remaining = delta; // Remaining flow to distribute
+        const entryMap = new Map(flowDistribution.map(entry => [entry.machineId, entry])); // Map for quick access
+
+        // Loop until remaining flow is within tolerance
+        while (Math.abs(remaining) > tolerance) {
+            const increasing = remaining > 0; // Determine if we are increasing or decreasing flow
+            // Build candidates with capacity and weight
+            const candidates = pumpInfos.map(info => {
+                const entry = entryMap.get(info.id);
+                if (!entry) { return null; }
+                const capacity = increasing ? info.maxFlow - entry.flow : entry.flow - info.minFlow; // Calculate available capacity based on direction
+                if (capacity <= tolerance) { return null; }
+
+                const slope = increasing
+                    ? (directional ? info.slopes.slopeRight : info.slopes.alpha)
+                    : (directional ? info.slopes.slopeLeft : info.slopes.alpha);
+
+                const weight = 1 / Math.max(1e-6, Math.abs(slope) || info.slopes.alpha || 1);
+                return { entry, capacity, weight };
+            }).filter(Boolean);
+
+            if (!candidates.length) { break; } // No candidates available, exit loop
+
+            const weightSum = candidates.reduce((sum, candidate) => sum + candidate.weight * candidate.capacity, 0); // weighted sum of capacities
+            if (weightSum <= 0) { break; } // Avoid division by zero
+
+            let progress = 0;
+            // Distribute remaining flow among candidates based on their weights and capacities
+            candidates.forEach(candidate => {
+                let share = (candidate.weight * candidate.capacity / weightSum) * Math.abs(remaining);
+                share = Math.min(share, candidate.capacity); // Ensure we don't exceed capacity
+                if (share <= 0) { return; } // Skip if no share to allocate
+                if (increasing) {
+                    candidate.entry.flow += share;
+                } else {
+                    candidate.entry.flow -= share;
+                }
+                progress += share; // Track total progress made in this iteration
+            });
+
+            if (progress <= tolerance) { break; }
+            remaining += increasing ? -progress : progress; // Update remaining flow to distribute
+        }
+    }
+
+    // BEP-gravitation based combination finder that biases allocation around each pump's BEP.
+    calcBestCombinationBEPGravitation(combinations, Qd, method = "BEP-Gravitation-Directional") {
+        let bestCombination = null;
+        let bestPower = Infinity;
+        let bestFlow = 0;
+        let bestCog = 0;
+        let bestDeviation = Infinity;
+        const directional = method === "BEP-Gravitation-Directional";
+
+        combinations.forEach(combination => {
+            const pumpInfos = combination.map(machineId => {
+                const machine = this.machines[machineId];
+                const minFlow = machine.predictFlow.currentFxyYMin;
+                const maxFlow = machine.predictFlow.currentFxyYMax;
+                const span = Math.max(0, maxFlow - minFlow);
+                const NCog = Math.max(0, Math.min(1, machine.NCog || 0));
+                const estimatedBEP = minFlow + span * NCog;  // Estimated BEP flow based on current curve
+                const slopes = this.estimateSlopesAtBEP(machine, estimatedBEP);
+                return {
+                    id: machineId,
+                    machine,
+                    minFlow,
+                    maxFlow,
+                    NCog,
+                    Q_BEP: slopes.Q_BEP,
+                    slopes
+                };
+            });
+
+            // Skip if no pumps in combination
+            if (pumpInfos.length === 0) { return; }
+
+            // Start at BEP flows
+            const flowDistribution = pumpInfos.map(info => ({
+                machineId: info.id,
+                flow: Math.min(info.maxFlow, Math.max(info.minFlow, info.Q_BEP))
+            }));
+
+            let totalFlow = flowDistribution.reduce((sum, entry) => sum + entry.flow, 0); // Initial total flow
+            const delta = Qd - totalFlow; // Difference to target demand
+            if (Math.abs(delta) > 1e-6) {
+                this.redistributeFlowBySlope(pumpInfos, flowDistribution, delta, directional);
+            }
+
+            // Clamp and compute initial power
+            flowDistribution.forEach(entry => {
+                const info = pumpInfos.find(info => info.id === entry.machineId);
+                entry.flow = Math.min(info.maxFlow, Math.max(info.minFlow, entry.flow));
+            });
+
+            // Marginal-cost refinement: shift flow from most expensive to cheapest
+            // pump using actual power evaluations. Converges regardless of curve convexity.
+            const mcDelta = Math.max(1e-6, (Qd / pumpInfos.length) * 0.005);
+            for (let refineIter = 0; refineIter < 50; refineIter++) {
+                const mcEntries = flowDistribution.map(entry => {
+                    const info = pumpInfos.find(i => i.id === entry.machineId);
+                    const pNow = info.machine.inputFlowCalcPower(entry.flow);
+                    const pUp = info.machine.inputFlowCalcPower(Math.min(info.maxFlow, entry.flow + mcDelta));
+                    return { entry, info, mc: (pUp - pNow) / mcDelta };
+                });
+                let expensive = null, cheap = null;
+                for (const e of mcEntries) {
+                    if (e.entry.flow > e.info.minFlow + mcDelta) { if (!expensive || e.mc > expensive.mc) expensive = e; }
+                    if (e.entry.flow < e.info.maxFlow - mcDelta) { if (!cheap || e.mc < cheap.mc) cheap = e; }
+                }
+                if (!expensive || !cheap || expensive === cheap) break;
+                if (expensive.mc - cheap.mc < expensive.mc * 0.001) break;
+                const before = expensive.info.machine.inputFlowCalcPower(expensive.entry.flow) + cheap.info.machine.inputFlowCalcPower(cheap.entry.flow);
+                const after = expensive.info.machine.inputFlowCalcPower(expensive.entry.flow - mcDelta) + cheap.info.machine.inputFlowCalcPower(cheap.entry.flow + mcDelta);
+                if (after < before) { expensive.entry.flow -= mcDelta; cheap.entry.flow += mcDelta; } else { break; }
+            }
+
+            let totalPower = 0;
+            totalFlow = 0;
+            flowDistribution.forEach(entry => {
+                totalFlow += entry.flow;
+                const info = pumpInfos.find(i => i.id === entry.machineId);
+                totalPower += info.machine.inputFlowCalcPower(entry.flow);
+            });
+
+            const totalCog = pumpInfos.reduce((sum, info) => sum + info.NCog, 0);
+            const deviation = pumpInfos.reduce((sum, info) => {
+                const entry = flowDistribution.find(item => item.machineId === info.id);
+                const deltaFlow = entry ? (entry.flow - info.Q_BEP) : 0;
+                return sum + (deltaFlow * deltaFlow) * (info.slopes.alpha || 1);
+            }, 0);
+
+            const shouldUpdate = totalPower < bestPower ||
+                (totalPower === bestPower && deviation < bestDeviation);
+
+            if (shouldUpdate) {
+                bestCombination = flowDistribution.map(entry => ({ ...entry }));
+                bestPower = totalPower;
+                bestFlow = totalFlow;
+                bestCog = totalCog;
+                bestDeviation = deviation;
+            }
+        });
+
+        return {
+            bestCombination,
+            bestPower,
+            bestFlow,
+            bestCog,
+            bestDeviation,
+            method
+        };
+    }
+
+
     // -------- Mode and Input Management -------- //
     isValidActionForMode(action, mode) {
         const allowedActionsSet = this.config.mode.allowedActions[mode] || [];
@@ -387,12 +671,17 @@ class MachineGroup {
     async optimalControl(Qd, powerCap = Infinity) {
 
         try{
+            if (Object.keys(this.machines).length === 0) {
+                this.logger.warn("No machines registered. Cannot execute optimal control.");
+                return;
+            }
+
             //we need to force the pressures of all machines to be equal to the highest pressure measured in the group
             // this is to ensure a correct evaluation of the flow and power consumption
             const pressures = Object.entries(this.machines).map(([_machineId, machine]) => {
                 return {
-                    downstream: machine.measurements.type("pressure").variant("measured").position(POSITIONS.DOWNSTREAM).getCurrentValue(),
+                    downstream: this._readChildMeasurement(machine, "pressure", "measured", POSITIONS.DOWNSTREAM, this.unitPolicy.canonical.pressure) || 0,
-                    upstream: machine.measurements.type("pressure").variant("measured").position(POSITIONS.UPSTREAM).getCurrentValue()
+                    upstream: this._readChildMeasurement(machine, "pressure", "measured", POSITIONS.UPSTREAM, this.unitPolicy.canonical.pressure) || 0
                 };
             });
 
@@ -406,8 +695,8 @@ class MachineGroup {
                 if(machine.state.getCurrentState() !== "operational" && machine.state.getCurrentState() !== "accelerating" && machine.state.getCurrentState() !== "decelerating"){
 
                     //Equilize pressures over all machines so we can make a proper calculation
-                    machine.measurements.type("pressure").variant("measured").position(POSITIONS.DOWNSTREAM).value(maxDownstream);
+                    this._writeChildMeasurement(machine, "pressure", "measured", POSITIONS.DOWNSTREAM, maxDownstream, this.unitPolicy.canonical.pressure);
-                    machine.measurements.type("pressure").variant("measured").position(POSITIONS.UPSTREAM).value(minUpstream);
+                    this._writeChildMeasurement(machine, "pressure", "measured", POSITIONS.UPSTREAM, minUpstream, this.unitPolicy.canonical.pressure);
 
                     // after updating the measurement directly we need to force the update of the value OLIFANT this is not so clear now in the code
                     // we need to find a better way to do this but for now it works
@@ -424,7 +713,9 @@ class MachineGroup {
             }, {});
 
             if( Qd <= 0 ) {
-                //if Qd is 0 turn all machines off and exit early
+                this.logger.debug("Flow demand <= 0, turning all machines off.");
+                await this.turnOffAllMachines();
+                return;
             }
 
             if( Qd < dynamicTotals.flow.min && Qd > 0 ){
@@ -440,7 +731,26 @@ class MachineGroup {
 
             // fetch all valid combinations that meet expectations
             const combinations = this.validPumpCombinations(this.machines, Qd, powerCap);
-            const bestResult = this.calcBestCombination(combinations, Qd);
+
+            if (!combinations || combinations.length === 0) {
+                this.logger.warn(`Demand: ${Qd.toFixed(2)} -> No valid combination found (empty set).`);
+                return;
+            }
+
+            // Decide which optimization routine we run. Defaults to BEP-based gravitation with directionality.
+            const optimizationMethod = this.config.optimization?.method || "BEP-Gravitation-Directional";
+            let bestResult;
+            if (optimizationMethod === "NCog") {
+                bestResult = this.calcBestCombination(combinations, Qd);
+            } else if (
+                optimizationMethod === "BEP-Gravitation" ||
+                optimizationMethod === "BEP-Gravitation-Directional"
+            ) {
+                bestResult = this.calcBestCombinationBEPGravitation(combinations, Qd, optimizationMethod);
+            } else {
+                this.logger.warn(`Unknown optimization method '${optimizationMethod}', falling back to BEP-Gravitation-Directional.`);
+                bestResult = this.calcBestCombinationBEPGravitation(combinations, Qd, "BEP-Gravitation-Directional");
+            }
 
             if(bestResult.bestCombination === null){
                 this.logger.warn(`Demand: ${Qd.toFixed(2)} -> No valid combination found => not updating control `);
@@ -451,8 +761,8 @@ class MachineGroup {
             this.logger.debug(`Moving to demand: ${Qd.toFixed(2)} -> Pumps: [${debugInfo}] => Total Power: ${bestResult.bestPower.toFixed(2)}`);
 
             //store the total delivered power
-            this.measurements.type("power").variant("predicted").position(POSITIONS.AT_EQUIPMENT).value(bestResult.bestPower);
+            this._writeMeasurement("power", "predicted", POSITIONS.AT_EQUIPMENT, bestResult.bestPower, this.unitPolicy.canonical.power);
-            this.measurements.type("flow").variant("predicted").position(POSITIONS.DOWNSTREAM).value(bestResult.bestFlow);
+            this._writeMeasurement("flow", "predicted", POSITIONS.DOWNSTREAM, bestResult.bestFlow, this.unitPolicy.canonical.flow);
             this.measurements.type("efficiency").variant("predicted").position(POSITIONS.AT_EQUIPMENT).value(bestResult.bestFlow / bestResult.bestPower);
             this.measurements.type("Ncog").variant("predicted").position(POSITIONS.AT_EQUIPMENT).value(bestResult.bestCog);
 
@@ -469,16 +779,16 @@ class MachineGroup {
                     }
 
                     if( (flow <= 0 ) && ( machineStates[machineId] === "operational" || machineStates[machineId] === "accelerating" || machineStates[machineId] === "decelerating" ) ){
-                        await machine.handleInput("parent", "execSequence", "shutdown");
+                        await machine.handleInput("parent", "execsequence", "shutdown");
                     }
 
                     if(machineStates[machineId] === "idle" && flow > 0){
-                        await machine.handleInput("parent", "execSequence", "startup");
+                        await machine.handleInput("parent", "execsequence", "startup");
-                        await machine.handleInput("parent", "flowMovement", flow);
+                        await machine.handleInput("parent", "flowmovement", this._canonicalToOutputFlow(flow));
                     }
 
                     if(machineStates[machineId] === "operational" && flow > 0 ){
-                        await machine.handleInput("parent", "flowMovement", flow);
+                        await machine.handleInput("parent", "flowmovement", this._canonicalToOutputFlow(flow));
                     }
             }));
         }
@@ -489,11 +799,13 @@ class MachineGroup {
 
     // Equalize pressure across all machines for machines that are not running. This is needed to ensure accurate flow and power predictions.
     equalizePressure(){
+        if (Object.keys(this.machines).length === 0) return;
+
         // Get current pressures from all machines
         const pressures = Object.entries(this.machines).map(([_machineId, machine]) => {
             return {
-                downstream: machine.measurements.type("pressure").variant("measured").position(POSITIONS.DOWNSTREAM).getCurrentValue(),
+                downstream: this._readChildMeasurement(machine, "pressure", "measured", POSITIONS.DOWNSTREAM, this.unitPolicy.canonical.pressure) || 0,
-                upstream: machine.measurements.type("pressure").variant("measured").position(POSITIONS.UPSTREAM).getCurrentValue()
+                upstream: this._readChildMeasurement(machine, "pressure", "measured", POSITIONS.UPSTREAM, this.unitPolicy.canonical.pressure) || 0
             };
         });
 
@@ -504,8 +816,8 @@ class MachineGroup {
         // Set consistent pressures across machines
         Object.entries(this.machines).forEach(([machineId, machine]) => {
             if(!this.isMachineActive(machineId)){
-                machine.measurements.type("pressure").variant("measured").position(POSITIONS.DOWNSTREAM).value(maxDownstream);
+                this._writeChildMeasurement(machine, "pressure", "measured", POSITIONS.DOWNSTREAM, maxDownstream, this.unitPolicy.canonical.pressure);
-                machine.measurements.type("pressure").variant("measured").position(POSITIONS.UPSTREAM).value(minUpstream);
+                this._writeChildMeasurement(machine, "pressure", "measured", POSITIONS.UPSTREAM, minUpstream, this.unitPolicy.canonical.pressure);
                 // Update the measured pressure value
                 const pressure = machine.getMeasuredPressure();
                 this.logger.debug(`Setting pressure for machine ${machineId} to ${pressure}`);
@@ -551,7 +863,7 @@ class MachineGroup {
     filterOutUnavailableMachines(list) {
         const newList = list.filter(({ machine }) => {
             const state = machine.state.getCurrentState();
-            const validActionForMode = machine.isValidActionForMode("execSequence", "auto");
+            const validActionForMode = machine.isValidActionForMode("execsequence", "auto");
 
             return !(state === "off" || state === "coolingdown" || state === "stopping" || state === "emergencystop" || !validActionForMode);
         });
@@ -683,8 +995,8 @@ class MachineGroup {
             this.logger.debug(`Priority control for demand: ${totalFlow.toFixed(2)} -> Active pumps: [${debugInfo}] => Total Power: ${totalPower.toFixed(2)}`);
 
             // Store measurements
-            this.measurements.type("power").variant("predicted").position(POSITIONS.AT_EQUIPMENT).value(totalPower);
+            this._writeMeasurement("power", "predicted", POSITIONS.AT_EQUIPMENT, totalPower, this.unitPolicy.canonical.power);
-            this.measurements.type("flow").variant("predicted").position(POSITIONS.DOWNSTREAM).value(totalFlow);
+            this._writeMeasurement("flow", "predicted", POSITIONS.DOWNSTREAM, totalFlow, this.unitPolicy.canonical.flow);
             this.measurements.type("efficiency").variant("predicted").position(POSITIONS.AT_EQUIPMENT).value(totalFlow / totalPower);
             this.measurements.type("Ncog").variant("predicted").position(POSITIONS.AT_EQUIPMENT).value(totalCog);
 
@@ -696,13 +1008,14 @@ class MachineGroup {
                 const currentState = this.machines[machineId].state.getCurrentState();
 
                 if (flow <= 0 && (currentState === "operational" || currentState === "accelerating" || currentState === "decelerating")) {
-                    await machine.handleInput("parent", "execSequence", "shutdown");
+                    await machine.handleInput("parent", "execsequence", "shutdown");
                 }
                 else if (currentState === "idle" && flow > 0) {
-                    await machine.handleInput("parent", "execSequence", "startup");
+                    await machine.handleInput("parent", "execsequence", "startup");
+                    await machine.handleInput("parent", "flowmovement", this._canonicalToOutputFlow(flow));
                 }
                 else if (currentState === "operational" && flow > 0) {
-                    await machine.handleInput("parent", "flowMovement", flow);
+                    await machine.handleInput("parent", "flowmovement", this._canonicalToOutputFlow(flow));
                 }
             }));
         }
@@ -718,7 +1031,7 @@ class MachineGroup {
             if(input < 0 ){
                 //turn all machines off
                 await Promise.all(Object.entries(this.machines).map(async ([machineId, machine]) => {
-                    if (this.isMachineActive(machineId)) { await machine.handleInput("parent", "execSequence", "shutdown"); }
+                    if (this.isMachineActive(machineId)) { await machine.handleInput("parent", "execsequence", "shutdown"); }
                 }));
                 return;
             }
@@ -782,13 +1095,13 @@ class MachineGroup {
                 const currentState = this.machines[machineId].state.getCurrentState();
 
                 if (ctrl < 0 && (currentState === "operational" || currentState === "accelerating" || currentState === "decelerating")) {
-                    await machine.handleInput("parent", "execSequence", "shutdown");
+                    await machine.handleInput("parent", "execsequence", "shutdown");
                 }
                 else if (currentState === "idle" && ctrl >= 0) {
-                    await machine.handleInput("parent", "execSequence", "startup");
+                    await machine.handleInput("parent", "execsequence", "startup");
                 }
                 else if (currentState === "operational" && ctrl > 0) {
-                    await machine.handleInput("parent", "execMovement", ctrl);
+                    await machine.handleInput("parent", "execmovement", ctrl);
                 }
             }));
 
@@ -798,8 +1111,8 @@ class MachineGroup {
             // fetch and store measurements
             Object.entries(this.machines).forEach(([_machineId, machine]) => {
 
-                const powerValue = machine.measurements.type("power").variant("predicted").position(POSITIONS.AT_EQUIPMENT).getCurrentValue();
+                const powerValue = this._readChildMeasurement(machine, "power", "predicted", POSITIONS.AT_EQUIPMENT, this.unitPolicy.canonical.power);
-                const flowValue = machine.measurements.type("flow").variant("predicted").position(POSITIONS.DOWNSTREAM).getCurrentValue();
+                const flowValue = this._readChildMeasurement(machine, "flow", "predicted", POSITIONS.DOWNSTREAM, this.unitPolicy.canonical.flow);
 
                 if (powerValue !== null) {
                     totalPower.push(powerValue);
@@ -809,8 +1122,8 @@ class MachineGroup {
                 }
             });
 
-            this.measurements.type("power").variant("predicted").position(POSITIONS.AT_EQUIPMENT).value(totalPower.reduce((a, b) => a + b, 0));
+            this._writeMeasurement("power", "predicted", POSITIONS.AT_EQUIPMENT, totalPower.reduce((a, b) => a + b, 0), this.unitPolicy.canonical.power);
-            this.measurements.type("flow").variant("predicted").position(POSITIONS.DOWNSTREAM).value(totalFlow.reduce((a, b) => a + b, 0));
+            this._writeMeasurement("flow", "predicted", POSITIONS.DOWNSTREAM, totalFlow.reduce((a, b) => a + b, 0), this.unitPolicy.canonical.flow);
 
             if(totalPower.reduce((a, b) => a + b, 0) > 0){
                 this.measurements.type("efficiency").variant("predicted").position(POSITIONS.AT_EQUIPMENT).value(totalFlow.reduce((a, b) => a + b, 0) / totalPower.reduce((a, b) => a + b, 0));
@@ -824,13 +1137,19 @@ class MachineGroup {
 
     async handleInput(source, demand, powerCap = Infinity, priorityList = null) {
 
+        const demandQ = parseFloat(demand);
+
+        if(!Number.isFinite(demandQ)){
+            this.logger.error(`Invalid flow demand input: ${demand}. Must be a finite number.`);
+            return;
+        }
+
         //abort current movements
         await this.abortActiveMovements("new demand received");
 
         const scaling = this.scaling;
         const mode = this.mode;
         const dynamicTotals = this.calcDynamicTotals();
-        const demandQ = parseFloat(demand);
         let demandQout = 0; // keep output Q by default 0 for safety
 
         this.logger.debug(`Handling input from ${source}: Demand = ${demand}, Power Cap = ${powerCap}, Priority List = ${priorityList}`);
@@ -843,23 +1162,23 @@ class MachineGroup {
                     return;
                 }
 
-                if (demandQ < this.absoluteTotals.flow.min) {
+                if (demandQ <= 0) {
-                    this.logger.warn(`Flow demand ${demandQ} is below minimum possible flow ${this.absoluteTotals.flow.min}. Capping to minimum flow.`);
-                    demandQout = this.absoluteTotals.flow.min;
-                } else if (demandQout > this.absoluteTotals.flow.max) {
-                    this.logger.warn(`Flow demand ${demandQ} is above maximum possible flow ${this.absoluteTotals.flow.max}. Capping to maximum flow.`);
-                    demandQout = this.absoluteTotals.flow.max;
-                }else if(demandQout <= 0){
                     this.logger.debug(`Turning machines off`);
                     demandQout = 0;
-                    //return early and turn all machines off
                     this.turnOffAllMachines();
                     return;
+                } else if (demandQ < this.absoluteTotals.flow.min) {
+                    this.logger.warn(`Flow demand ${demandQ} is below minimum possible flow ${this.absoluteTotals.flow.min}. Capping to minimum flow.`);
+                    demandQout = this.absoluteTotals.flow.min;
+                } else if (demandQ > this.absoluteTotals.flow.max) {
+                    this.logger.warn(`Flow demand ${demandQ} is above maximum possible flow ${this.absoluteTotals.flow.max}. Capping to maximum flow.`);
+                    demandQout = this.absoluteTotals.flow.max;
+                } else {
+                    demandQout = demandQ;
                 }
                 break;
 
             case "normalized":
-
                 this.logger.debug(`Normalizing flow demand: ${demandQ} with min: ${dynamicTotals.flow.min} and max: ${dynamicTotals.flow.max}`);
                 if(demand < 0){
                     this.logger.debug(`Turning machines off`);
@@ -877,7 +1196,6 @@ class MachineGroup {
         }
 
 
-
         // Execute control based on mode
         switch(mode) {
             case "prioritycontrol":
@@ -906,17 +1224,124 @@ class MachineGroup {
 
         //recalc distance from BEP
         const { maxEfficiency, lowestEfficiency } = this.calcGroupEfficiency(this.machines);
-        const efficiency = this.measurements.type("efficiency").variant("predicted").position(POSITIONS.DOWNSTREAM).getCurrentValue();
+        const efficiency = this.measurements.type("efficiency").variant("predicted").position(POSITIONS.AT_EQUIPMENT).getCurrentValue();
         this.calcDistanceBEP(efficiency,maxEfficiency,lowestEfficiency);
 
     }
 
     async turnOffAllMachines(){
         await Promise.all(Object.entries(this.machines).map(async ([machineId, machine]) => {
-            if (this.isMachineActive(machineId)) { await machine.handleInput("parent", "execSequence", "shutdown"); }
+            if (this.isMachineActive(machineId)) { await machine.handleInput("parent", "execsequence", "shutdown"); }
         }));
     }
 
+    _buildUnitPolicy(config = {}) {
+        const flowUnit = this._resolveUnitOrFallback(
+            config?.general?.unit,
+            'volumeFlowRate',
+            DEFAULT_IO_UNITS.flow
+        );
+        const pressureUnit = this._resolveUnitOrFallback(
+            config?.general?.pressureUnit,
+            'pressure',
+            DEFAULT_IO_UNITS.pressure
+        );
+        const powerUnit = this._resolveUnitOrFallback(
+            config?.general?.powerUnit,
+            'power',
+            DEFAULT_IO_UNITS.power
+        );
+
+        return {
+            canonical: { ...CANONICAL_UNITS },
+            output: {
+                flow: flowUnit,
+                pressure: pressureUnit,
+                power: powerUnit,
+                temperature: DEFAULT_IO_UNITS.temperature,
+            },
+        };
+    }
+
+    _resolveUnitOrFallback(candidate, expectedMeasure, fallbackUnit) {
+        const fallback = String(fallbackUnit || '').trim();
+        const raw = typeof candidate === 'string' ? candidate.trim() : '';
+        if (!raw) {
+            return fallback;
+        }
+        try {
+            const desc = convert().describe(raw);
+            if (expectedMeasure && desc.measure !== expectedMeasure) {
+                throw new Error(`expected '${expectedMeasure}', got '${desc.measure}'`);
+            }
+            return raw;
+        } catch (error) {
+            this.logger?.warn?.(`Invalid unit '${raw}' (${error.message}); falling back to '${fallback}'.`);
+            return fallback;
+        }
+    }
+
+    _canonicalToOutputFlow(value) {
+        const from = this.unitPolicy.canonical.flow;
+        const to = this.unitPolicy.output.flow;
+        if (!from || !to || from === to) return value;
+        return convert(value).from(from).to(to);
+    }
+
+    _outputUnitForType(type) {
+        switch (String(type || '').toLowerCase()) {
+            case 'flow':
+                return this.unitPolicy.output.flow;
+            case 'power':
+                return this.unitPolicy.output.power;
+            case 'pressure':
+                return this.unitPolicy.output.pressure;
+            case 'temperature':
+                return this.unitPolicy.output.temperature;
+            default:
+                return null;
+        }
+    }
+
+    _readMeasurement(type, variant, position, unit = null) {
+        const requestedUnit = unit || this._outputUnitForType(type);
+        return this.measurements
+            .type(type)
+            .variant(variant)
+            .position(position)
+            .getCurrentValue(requestedUnit || undefined);
+    }
+
+    _writeMeasurement(type, variant, position, value, unit = null, timestamp = Date.now()) {
+        if (!Number.isFinite(value)) {
+            return;
+        }
+        this.measurements
+            .type(type)
+            .variant(variant)
+            .position(position)
+            .value(value, timestamp, unit || undefined);
+    }
+
+    _readChildMeasurement(machine, type, variant, position, unit = null) {
+        return machine?.measurements
+            ?.type(type)
+            ?.variant(variant)
+            ?.position(position)
+            ?.getCurrentValue(unit || undefined);
+    }
+
+    _writeChildMeasurement(machine, type, variant, position, value, unit = null, timestamp = Date.now()) {
+        if (!machine?.measurements || !Number.isFinite(value)) {
+            return;
+        }
+        machine.measurements
+            .type(type)
+            .variant(variant)
+            .position(position)
+            .value(value, timestamp, unit || undefined);
+    }
+
     setMode(mode) {
         this.mode = mode;
     }
@@ -929,10 +1354,10 @@ class MachineGroup {
         //build the output object
         this.measurements.getTypes().forEach(type => {
           this.measurements.getVariants(type).forEach(variant => {
-    
+            const unit = this._outputUnitForType(type);
-            const downstreamVal = this.measurements.type(type).variant(variant).position(POSITIONS.DOWNSTREAM).getCurrentValue();
+            const downstreamVal = this._readMeasurement(type, variant, POSITIONS.DOWNSTREAM, unit);
-            const atEquipmentVal = this.measurements.type(type).variant(variant).position(POSITIONS.AT_EQUIPMENT).getCurrentValue();
+            const atEquipmentVal = this._readMeasurement(type, variant, POSITIONS.AT_EQUIPMENT, unit);
-            const upstreamVal = this.measurements.type(type).variant(variant).position(POSITIONS.UPSTREAM).getCurrentValue();
+            const upstreamVal = this._readMeasurement(type, variant, POSITIONS.UPSTREAM, unit);
 
             if (downstreamVal != null) {
               output[`downstream_${variant}_${type}`] = downstreamVal;
@@ -944,8 +1369,13 @@ class MachineGroup {
               output[`atEquipment_${variant}_${type}`] = atEquipmentVal;
             }
             if (downstreamVal != null && upstreamVal != null) {
-              const diffVal = this.measurements.type(type).variant(variant).difference().value;
+              const diff = this.measurements
-              output[`differential_${variant}_${type}`] = diffVal;
+                  .type(type)
+                  .variant(variant)
+                  .difference({ from: POSITIONS.DOWNSTREAM, to: POSITIONS.UPSTREAM, unit });
+              if (diff?.value != null) {
+                  output[`differential_${variant}_${type}`] = diff.value;
+              }
             }
           });
         });
@@ -967,7 +1397,7 @@ class MachineGroup {
 
 module.exports = MachineGroup;
 /*
-
+const {coolprop} = require('generalFunctions');
 const Machine = require('../../rotatingMachine/src/specificClass');
 const Measurement = require('../../measurement/src/specificClass');
 const specs = require('../../generalFunctions/datasets/assetData/curves/hidrostal-H05K-S03R.json');
@@ -995,9 +1425,9 @@ function createBaseMachineConfig(machineNum, name,specs) {
         mode: {
             current: "auto",
             allowedActions: {
-                auto: ["execSequence", "execMovement", "statusCheck"],
+                auto: ["execsequence", "execmovement", "statuscheck"],
-                virtualControl: ["execMovement", "statusCheck"],
+                virtualControl: ["execmovement", "statuscheck"],
-                fysicalControl: ["statusCheck"]
+                fysicalControl: ["statuscheck"]
             },
             allowedSources: {
                 auto: ["parent", "GUI"],
@@ -1089,11 +1519,11 @@ async function makeMachines(){
         for(let i = 1; i <= numofMachines; i++){
             const machine = new Machine(machineConfigs[i],stateConfigs[i]);
             //mg.machines[i] = machine;
-            mg.childRegistrationUtils.registerChild(machine, POSITIONS.DOWNSTREAM);
+            mg.childRegistrationUtils.registerChild(machine, "downstream");
         }
 
         Object.keys(mg.machines).forEach(machineId => {
-            mg.machines[machineId].childRegistrationUtils.registerChild(pt1, POSITIONS.DOWNSTREAM);
+            mg.machines[machineId].childRegistrationUtils.registerChild(pt1, "downstream");
         });
 
         mg.setMode("prioritycontrol");
@@ -1105,7 +1535,7 @@ async function makeMachines(){
         const percMax = 100;
 
         try{
-           /*
+
             for(let demand = mg.dynamicTotals.flow.min ; demand <= mg.dynamicTotals.flow.max ; demand += 2){
                 //set pressure
 
@@ -1155,6 +1585,8 @@ async function makeMachines(){
 }
 
 
-makeMachines();
+if (require.main === module) {
+  makeMachines();
+}
 
 //*/

test/README.md

@@ -0,0 +1,12 @@
+# machineGroupControl Test Suite Layout
+
+Required EVOLV layout:
+- basic/
+- integration/
+- edge/
+- helpers/
+
+Baseline structure tests:
+- basic/structure-module-load.basic.test.js
+- integration/structure-examples.integration.test.js
+- edge/structure-examples-node-type.edge.test.js

test/basic/structure-module-load.basic.test.js

@@ -0,0 +1,8 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+test('machineGroupControl module load smoke', () => {
+  assert.doesNotThrow(() => {
+    require('../../mgc.js');
+  });
+});

test/edge/structure-examples-node-type.edge.test.js

@@ -0,0 +1,11 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const flow = JSON.parse(fs.readFileSync(path.resolve(__dirname, '../../examples/basic.flow.json'), 'utf8'));
+
+test('basic example includes node type machineGroupControl', () => {
+  const count = flow.filter((n) => n && n.type === 'machineGroupControl').length;
+  assert.equal(count >= 1, true);
+});

test/integration/distribution-power-table.integration.test.js

@@ -0,0 +1,227 @@
+/**
+ * machineGroupControl vs naive strategies — real pump curves
+ *
+ * Station: 2× hidrostal H05K-S03R + 1× hidrostal C5-D03R-SHN1
+ * ΔP = 2000 mbar
+ *
+ * Compares the ACTUAL machineGroupControl optimalControl algorithm against
+ * naive baselines. All strategies must deliver exactly Qd.
+ */
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const MachineGroup = require('../../src/specificClass');
+const Machine = require('../../../rotatingMachine/src/specificClass');
+
+const DIFF_MBAR = 2000;
+const UP_MBAR = 500;
+const DOWN_MBAR = UP_MBAR + DIFF_MBAR;
+
+const stateConfig = {
+  time: { starting: 0, warmingup: 0, stopping: 0, coolingdown: 0 },
+  movement: { speed: 1200, mode: 'staticspeed', maxSpeed: 1800 }
+};
+
+function machineConfig(id, model) {
+  return {
+    general: { logging: { enabled: false, logLevel: 'error' }, name: id, id, unit: 'm3/h' },
+    functionality: { softwareType: 'machine', role: 'rotationaldevicecontroller' },
+    asset: { category: 'pump', type: 'centrifugal', model, supplier: 'hidrostal' },
+    mode: {
+      current: 'auto',
+      allowedActions: { auto: ['execsequence', 'execmovement', 'flowmovement', 'statuscheck'] },
+      allowedSources: { auto: ['parent', 'GUI'] }
+    },
+    sequences: {
+      startup: ['starting', 'warmingup', 'operational'],
+      shutdown: ['stopping', 'coolingdown', 'idle'],
+      emergencystop: ['emergencystop', 'off'],
+    }
+  };
+}
+
+function groupConfig() {
+  return {
+    general: { logging: { enabled: false, logLevel: 'error' }, name: 'station' },
+    functionality: { softwareType: 'machinegroup', role: 'groupcontroller' },
+    scaling: { current: 'absolute' },
+    mode: { current: 'optimalcontrol' }
+  };
+}
+
+function injectPressure(m) {
+  m.updateMeasuredPressure(UP_MBAR, 'upstream', { timestamp: Date.now(), unit: 'mbar', childName: 'up', childId: `up-${m.config.general.id}` });
+  m.updateMeasuredPressure(DOWN_MBAR, 'downstream', { timestamp: Date.now(), unit: 'mbar', childName: 'dn', childId: `dn-${m.config.general.id}` });
+}
+
+/* ---- naive baselines (pumps OFF = 0 flow, 0 power) ---- */
+
+function distribute(machines, running, rawDist, Qd) {
+  const dist = {};
+  for (const id of Object.keys(machines)) dist[id] = 0;
+  for (const id of running) {
+    const m = machines[id];
+    dist[id] = Math.min(m.predictFlow.currentFxyYMax, Math.max(m.predictFlow.currentFxyYMin, rawDist[id] || 0));
+  }
+  for (let pass = 0; pass < 20; pass++) {
+    let rem = Qd - running.reduce((s, id) => s + dist[id], 0);
+    if (Math.abs(rem) < 1e-9) break;
+    for (const id of running) {
+      if (Math.abs(rem) < 1e-9) break;
+      const m = machines[id];
+      const cap = rem > 0 ? m.predictFlow.currentFxyYMax - dist[id] : dist[id] - m.predictFlow.currentFxyYMin;
+      if (cap > 1e-9) { const t = Math.min(Math.abs(rem), cap); dist[id] += rem > 0 ? t : -t; rem += rem > 0 ? -t : t; }
+    }
+  }
+  return dist;
+}
+
+function spillover(machines, Qd) {
+  const sorted = Object.keys(machines).sort((a, b) => machines[a].predictFlow.currentFxyYMax - machines[b].predictFlow.currentFxyYMax);
+  let running = [], maxCap = 0;
+  for (const id of sorted) { running.push(id); maxCap += machines[id].predictFlow.currentFxyYMax; if (maxCap >= Qd) break; }
+  const raw = {}; let rem = Qd;
+  for (const id of running) { raw[id] = rem; rem = Math.max(0, rem - machines[id].predictFlow.currentFxyYMax); }
+  const dist = distribute(machines, running, raw, Qd);
+  let p = 0, f = 0;
+  for (const id of running) { p += machines[id].inputFlowCalcPower(dist[id]); f += dist[id]; }
+  return { dist, power: p, flow: f, combo: running };
+}
+
+function equalAllOn(machines, Qd) {
+  const ids = Object.keys(machines);
+  const raw = {}; for (const id of ids) raw[id] = Qd / ids.length;
+  const dist = distribute(machines, ids, raw, Qd);
+  let p = 0, f = 0;
+  for (const id of ids) { p += machines[id].inputFlowCalcPower(dist[id]); f += dist[id]; }
+  return { dist, power: p, flow: f, combo: ids };
+}
+
+/* ---- test ---- */
+
+test('machineGroupControl vs naive baselines — real curves, verified flow', async () => {
+  const mg = new MachineGroup(groupConfig());
+  const machines = {};
+
+  for (const [id, model] of [['H05K-1','hidrostal-H05K-S03R'],['H05K-2','hidrostal-H05K-S03R'],['C5','hidrostal-C5-D03R-SHN1']]) {
+    const m = new Machine(machineConfig(id, model), stateConfig);
+    injectPressure(m);
+    mg.childRegistrationUtils.registerChild(m, 'downstream');
+    machines[id] = m;
+  }
+
+  const toH = (v) => +(v * 3600).toFixed(1);
+  const CANON_FLOW = 'm3/s';
+  const CANON_POWER = 'W';
+
+  console.log(`\n=== STATION: 2×H05K + 1×C5 @ ΔP=${DIFF_MBAR} mbar ===`);
+  console.table(Object.entries(machines).map(([id, m]) => ({
+    id,
+    'min (m³/h)': toH(m.predictFlow.currentFxyYMin),
+    'max (m³/h)': toH(m.predictFlow.currentFxyYMax),
+    'BEP (m³/h)': toH(m.predictFlow.currentFxyYMin + (m.predictFlow.currentFxyYMax - m.predictFlow.currentFxyYMin) * m.NCog),
+    NCog: +m.NCog.toFixed(3),
+  })));
+
+  const minQ = Math.max(...Object.values(machines).map(m => m.predictFlow.currentFxyYMin));
+  const maxQ = Object.values(machines).reduce((s, m) => s + m.predictFlow.currentFxyYMax, 0);
+  const demandPcts = [0.10, 0.25, 0.50, 0.75, 0.90];
+  const rows = [];
+
+  for (const pct of demandPcts) {
+    const Qd = minQ + (maxQ - minQ) * pct;
+
+    // Reset all machines to idle, re-inject pressure
+    for (const m of Object.values(machines)) {
+      if (m.state.getCurrentState() !== 'idle') await m.handleInput('parent', 'execSequence', 'shutdown');
+      injectPressure(m);
+    }
+
+    // Run machineGroupControl optimalControl with absolute scaling
+    mg.setMode('optimalcontrol');
+    mg.setScaling('absolute');
+    mg.calcAbsoluteTotals();
+    mg.calcDynamicTotals();
+    await mg.handleInput('parent', Qd);
+
+    // Read ACTUAL per-pump state (not the MGC summary which may be stale)
+    let mgcPower = 0, mgcFlow = 0;
+    const mgcCombo = [];
+    const mgcDist = {};
+    for (const [id, m] of Object.entries(machines)) {
+      const state = m.state.getCurrentState();
+      const flow = m.measurements.type('flow').variant('predicted').position('downstream').getCurrentValue(CANON_FLOW) || 0;
+      const power = m.measurements.type('power').variant('predicted').position('atequipment').getCurrentValue(CANON_POWER) || 0;
+      mgcDist[id] = { flow, power, state };
+      if (state === 'operational' || state === 'warmingup' || state === 'accelerating') {
+        mgcCombo.push(id);
+        mgcPower += power;
+        mgcFlow += flow;
+      }
+    }
+
+    // Naive baselines
+    const sp = spillover(machines, Qd);
+    const ea = equalAllOn(machines, Qd);
+
+    const best = Math.min(mgcPower, sp.power, ea.power);
+    const delta = (v) => best > 0 ? `${(((v - best) / best) * 100).toFixed(1)}%` : '';
+
+    rows.push({
+      demand: `${(pct * 100)}%`,
+      'Qd (m³/h)': toH(Qd),
+      'MGC kW': +(mgcPower / 1000).toFixed(1),
+      'MGC flow': toH(mgcFlow),
+      'MGC pumps': mgcCombo.join('+') || 'none',
+      'Spill kW': +(sp.power / 1000).toFixed(1),
+      'Spill flow': toH(sp.flow),
+      'Spill pumps': sp.combo.join('+'),
+      'EqAll kW': +(ea.power / 1000).toFixed(1),
+      'EqAll flow': toH(ea.flow),
+      'MGC Δ': delta(mgcPower),
+      'Spill Δ': delta(sp.power),
+      'EqAll Δ': delta(ea.power),
+    });
+  }
+
+  console.log('\n=== POWER + FLOW COMPARISON (★ = best, all must deliver Qd) ===');
+  console.table(rows);
+
+  // Per-pump detail at each demand level
+  for (const pct of demandPcts) {
+    const Qd = minQ + (maxQ - minQ) * pct;
+
+    for (const m of Object.values(machines)) {
+      if (m.state.getCurrentState() !== 'idle') await m.handleInput('parent', 'execSequence', 'shutdown');
+      injectPressure(m);
+    }
+    mg.setMode('optimalcontrol');
+    mg.setScaling('absolute');
+    mg.calcAbsoluteTotals();
+    mg.calcDynamicTotals();
+    await mg.handleInput('parent', Qd);
+
+    const detail = Object.entries(machines).map(([id, m]) => {
+      const state = m.state.getCurrentState();
+      const flow = m.measurements.type('flow').variant('predicted').position('downstream').getCurrentValue(CANON_FLOW) || 0;
+      const power = m.measurements.type('power').variant('predicted').position('atequipment').getCurrentValue(CANON_POWER) || 0;
+      return {
+        pump: id,
+        state,
+        'flow (m³/h)': toH(flow),
+        'power (kW)': +(power / 1000).toFixed(1),
+      };
+    });
+    console.log(`\n--- MGC per-pump @ ${(pct*100)}% (${toH(Qd)} m³/h) ---`);
+    console.table(detail);
+  }
+
+  // Flow verification on naive strategies
+  for (const pct of demandPcts) {
+    const Qd = minQ + (maxQ - minQ) * pct;
+    const sp = spillover(machines, Qd);
+    const ea = equalAllOn(machines, Qd);
+    assert.ok(Math.abs(sp.flow - Qd) < Qd * 0.005, `Spillover flow mismatch at ${(pct*100)}%`);
+    assert.ok(Math.abs(ea.flow - Qd) < Qd * 0.005, `Equal-all flow mismatch at ${(pct*100)}%`);
+  }
+});

test/integration/ncog-distribution.integration.test.js

@@ -0,0 +1,442 @@
+/**
+ * Group Distribution Strategy Comparison Test
+ *
+ * Compares three flow distribution strategies for a group of pumps:
+ *   1. NCog/BEP-Gravitation (slope-weighted — favours pumps with flatter power curves)
+ *   2. Equal distribution (same flow to every pump)
+ *   3. Spillover (fill smallest pump first, overflow to next)
+ *
+ * For variable-speed centrifugal pumps, specific flow (Q/P) is monotonically
+ * decreasing per pump (affinity laws: P ∝ Q³), so NCog = 0 for all pumps.
+ * The real optimization value comes from the BEP-Gravitation algorithm's
+ * slope-based redistribution, which IS sensitive to curve shape differences.
+ *
+ * These tests verify that:
+ * - Asymmetric pumps produce different power slopes (the basis for optimization)
+ * - BEP-Gravitation uses less total power than naive strategies for mixed pumps
+ * - Equal pumps receive equal treatment under all strategies
+ * - Spillover creates a visibly different distribution than BEP-weighted
+ */
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const MachineGroup = require('../../src/specificClass');
+const Machine = require('../../../rotatingMachine/src/specificClass');
+
+const baseCurve = require('../../../generalFunctions/datasets/assetData/curves/hidrostal-H05K-S03R.json');
+
+/* ---- helpers ---- */
+
+function deepClone(obj) { return JSON.parse(JSON.stringify(obj)); }
+
+function distortSeries(series, scale = 1, tilt = 0) {
+  const last = series.length - 1;
+  return series.map((v, i) => {
+    const gradient = last === 0 ? 0 : i / last - 0.5;
+    return Math.max(v * scale * (1 + tilt * gradient), 0);
+  });
+}
+
+function createSyntheticCurve(mods) {
+  const { flowScale = 1, powerScale = 1, flowTilt = 0, powerTilt = 0 } = mods;
+  const curve = deepClone(baseCurve);
+  Object.values(curve.nq).forEach(s => { s.y = distortSeries(s.y, flowScale, flowTilt); });
+  Object.values(curve.np).forEach(s => { s.y = distortSeries(s.y, powerScale, powerTilt); });
+  return curve;
+}
+
+const stateConfig = {
+  time: { starting: 0, warmingup: 0, stopping: 0, coolingdown: 0 },
+  movement: { speed: 1200, mode: 'staticspeed', maxSpeed: 1800 }
+};
+
+function createMachineConfig(id, label) {
+  return {
+    general: { logging: { enabled: false, logLevel: 'error' }, name: label, id, unit: 'm3/h' },
+    functionality: { softwareType: 'machine', role: 'rotationaldevicecontroller' },
+    asset: { category: 'pump', type: 'centrifugal', model: 'hidrostal-H05K-S03R', supplier: 'hidrostal' },
+    mode: {
+      current: 'auto',
+      allowedActions: { auto: ['execsequence', 'execmovement', 'flowmovement', 'statuscheck'] },
+      allowedSources: { auto: ['parent', 'GUI'] }
+    },
+    sequences: {
+      startup: ['starting', 'warmingup', 'operational'],
+      shutdown: ['stopping', 'coolingdown', 'idle'],
+      emergencystop: ['emergencystop', 'off'],
+    }
+  };
+}
+
+function createGroupConfig(name) {
+  return {
+    general: { logging: { enabled: false, logLevel: 'error' }, name },
+    functionality: { softwareType: 'machinegroup', role: 'groupcontroller' },
+    scaling: { current: 'normalized' },
+    mode: { current: 'optimalcontrol' }
+  };
+}
+
+/**
+ * Bootstrap with differential pressure (upstream + downstream) so the predict
+ * engine resolves a realistic fDimension and calcEfficiencyCurve produces
+ * a proper BEP peak — not a monotonic Q/P curve.
+ */
+function bootstrapGroup(name, machineSpecs, diffMbar, upstreamMbar = 800) {
+  const mg = new MachineGroup(createGroupConfig(name));
+  const machines = {};
+  for (const spec of machineSpecs) {
+    const m = new Machine(createMachineConfig(spec.id, spec.label), stateConfig);
+    if (spec.curveMods) m.updateCurve(createSyntheticCurve(spec.curveMods));
+    // Set BOTH upstream and downstream so getMeasuredPressure computes differential
+    m.updateMeasuredPressure(upstreamMbar, 'upstream', {
+      timestamp: Date.now(), unit: 'mbar', childName: `pt-up-${spec.id}`, childId: `pt-up-${spec.id}`
+    });
+    m.updateMeasuredPressure(upstreamMbar + diffMbar, 'downstream', {
+      timestamp: Date.now(), unit: 'mbar', childName: `pt-dn-${spec.id}`, childId: `pt-dn-${spec.id}`
+    });
+    mg.childRegistrationUtils.registerChild(m, 'downstream');
+    machines[spec.id] = m;
+  }
+  return { mg, machines };
+}
+
+/** Distribute flow weighted by each machine's NCog (BEP position). */
+function distributeByNCog(machines, Qd) {
+  const entries = Object.entries(machines);
+  let totalNCog = entries.reduce((s, [, m]) => s + (m.NCog || 0), 0);
+
+  const distribution = {};
+  for (const [id, m] of entries) {
+    const min = m.predictFlow.currentFxyYMin;
+    const max = m.predictFlow.currentFxyYMax;
+    const flow = totalNCog > 0
+      ? ((m.NCog || 0) / totalNCog) * Qd
+      : Qd / entries.length;
+    distribution[id] = Math.min(max, Math.max(min, flow));
+  }
+
+  let totalPower = 0;
+  for (const [id, m] of entries) {
+    totalPower += m.inputFlowCalcPower(distribution[id]);
+  }
+  return { distribution, totalPower };
+}
+
+/** Compute power at a given flow for a machine using its inverse curve. */
+function powerAtFlow(machine, flow) {
+  return machine.inputFlowCalcPower(flow);
+}
+
+/** Distribute by slope-weighting: flatter dP/dQ curves attract more flow. */
+function distributeBySlopeWeight(machines, Qd) {
+  const entries = Object.entries(machines);
+  // Estimate slope (dP/dQ) at midpoint for each machine
+  const pumpInfos = entries.map(([id, m]) => {
+    const min = m.predictFlow.currentFxyYMin;
+    const max = m.predictFlow.currentFxyYMax;
+    const mid = (min + max) / 2;
+    const delta = Math.max((max - min) * 0.05, 0.001);
+    const pMid = powerAtFlow(m, mid);
+    const pRight = powerAtFlow(m, Math.min(max, mid + delta));
+    const slope = Math.abs((pRight - pMid) / delta);
+    return { id, m, min, max, slope: Math.max(slope, 1e-6) };
+  });
+
+  // Weight = 1/slope: flatter curves get more flow
+  const totalWeight = pumpInfos.reduce((s, p) => s + (1 / p.slope), 0);
+  const distribution = {};
+  let totalPower = 0;
+
+  for (const p of pumpInfos) {
+    const weight = (1 / p.slope) / totalWeight;
+    const flow = Math.min(p.max, Math.max(p.min, Qd * weight));
+    distribution[p.id] = flow;
+    totalPower += powerAtFlow(p.m, flow);
+  }
+
+  return { distribution, totalPower };
+}
+
+/** Distribute equally. */
+function distributeEqual(machines, Qd) {
+  const entries = Object.entries(machines);
+  const flowEach = Qd / entries.length;
+  const distribution = {};
+  let totalPower = 0;
+  for (const [id, m] of entries) {
+    const min = m.predictFlow.currentFxyYMin;
+    const max = m.predictFlow.currentFxyYMax;
+    const clamped = Math.min(max, Math.max(min, flowEach));
+    distribution[id] = clamped;
+    totalPower += powerAtFlow(m, clamped);
+  }
+  return { distribution, totalPower };
+}
+
+/** Spillover: fill smallest pump to max first, then overflow to next. */
+function distributeSpillover(machines, Qd) {
+  const entries = Object.entries(machines)
+    .sort(([, a], [, b]) => a.predictFlow.currentFxyYMax - b.predictFlow.currentFxyYMax);
+  let remaining = Qd;
+  const distribution = {};
+  let totalPower = 0;
+  for (const [id, m] of entries) {
+    const min = m.predictFlow.currentFxyYMin;
+    const max = m.predictFlow.currentFxyYMax;
+    const assigned = Math.min(max, Math.max(min, remaining));
+    distribution[id] = assigned;
+    remaining = Math.max(0, remaining - assigned);
+  }
+  for (const [id, m] of entries) {
+    totalPower += powerAtFlow(m, distribution[id]);
+  }
+  return { distribution, totalPower };
+}
+
+/* ---- tests ---- */
+
+test('NCog is meaningful (0 < NCog ≤ 1) with proper differential pressure', () => {
+  const { machines } = bootstrapGroup('ncog-basic', [
+    { id: 'A', label: 'pump-A', curveMods: { flowScale: 1, powerScale: 1 } },
+  ], 400); // 400 mbar differential
+
+  const m = machines['A'];
+  assert.ok(Number.isFinite(m.NCog), `NCog should be finite, got ${m.NCog}`);
+  assert.ok(m.NCog > 0 && m.NCog <= 1, `NCog should be in (0,1], got ${m.NCog.toFixed(4)}`);
+  assert.ok(m.cog > 0, `cog (peak specific flow) should be positive, got ${m.cog}`);
+  assert.ok(m.cogIndex > 0, `BEP should not be at index 0 (that means monotonic Q/P with no real peak)`);
+});
+
+test('different curve shapes produce different NCog at same pressure', () => {
+  // powerTilt shifts the BEP position: positive tilt makes power steeper at high flow
+  // (BEP moves left), negative tilt makes it flatter at high flow (BEP moves right)
+  const { machines } = bootstrapGroup('ncog-shapes', [
+    { id: 'early', label: 'early-BEP', curveMods: { flowScale: 1, powerScale: 1, powerTilt: 0.4 } },
+    { id: 'late', label: 'late-BEP', curveMods: { flowScale: 1, powerScale: 1, powerTilt: -0.3 } },
+  ], 400);
+
+  const ncogEarly = machines['early'].NCog;
+  const ncogLate = machines['late'].NCog;
+
+  assert.ok(ncogEarly > 0, `Early BEP NCog should be > 0, got ${ncogEarly.toFixed(4)}`);
+  assert.ok(ncogLate > 0, `Late BEP NCog should be > 0, got ${ncogLate.toFixed(4)}`);
+  assert.ok(
+    ncogLate > ncogEarly,
+    `Late BEP pump should have higher NCog (BEP further into flow range). ` +
+    `early=${ncogEarly.toFixed(4)}, late=${ncogLate.toFixed(4)}`
+  );
+});
+
+test('NCog-weighted distribution differs from equal split for pumps with different BEPs', () => {
+  // Two pumps with different BEP positions (via powerTilt)
+  const { machines } = bootstrapGroup('ncog-vs-equal', [
+    { id: 'early', label: 'early-BEP', curveMods: { flowScale: 1, powerScale: 1, powerTilt: 0.4 } },
+    { id: 'late', label: 'late-BEP', curveMods: { flowScale: 1, powerScale: 1, powerTilt: -0.3 } },
+  ], 400);
+
+  const ncogA = machines['early'].NCog;
+  const ncogB = machines['late'].NCog;
+  assert.ok(ncogA > 0 && ncogB > 0, `Both NCog should be > 0 (early=${ncogA.toFixed(3)}, late=${ncogB.toFixed(3)})`);
+  assert.ok(ncogA !== ncogB, 'NCog values should differ');
+
+  const totalMax = machines['early'].predictFlow.currentFxyYMax + machines['late'].predictFlow.currentFxyYMax;
+  const Qd = totalMax * 0.5;
+
+  const ncogResult = distributeByNCog(machines, Qd);
+  const equalResult = distributeEqual(machines, Qd);
+
+  // NCog distributes proportionally to BEP position — late-BEP pump gets more flow
+  assert.ok(
+    ncogResult.distribution['late'] > ncogResult.distribution['early'],
+    `Late-BEP pump should get more flow under NCog. ` +
+    `early=${ncogResult.distribution['early'].toFixed(2)}, late=${ncogResult.distribution['late'].toFixed(2)}`
+  );
+
+  // Equal split gives same flow to both (they have same flow range, just different BEPs)
+  const equalDiff = Math.abs(equalResult.distribution['early'] - equalResult.distribution['late']);
+  const ncogDiff = Math.abs(ncogResult.distribution['early'] - ncogResult.distribution['late']);
+  assert.ok(
+    ncogDiff > equalDiff + Qd * 0.01,
+    `NCog distribution should be more asymmetric than equal split`
+  );
+});
+
+test('asymmetric pumps have different power curve slopes', () => {
+  // A pump with low powerScale has a flatter power curve
+  const { machines } = bootstrapGroup('slope-check', [
+    { id: 'flat', label: 'flat-power', curveMods: { flowScale: 1.2, powerScale: 0.7, flowTilt: 0.1 } },
+    { id: 'steep', label: 'steep-power', curveMods: { flowScale: 0.8, powerScale: 1.4, flowTilt: -0.05 } },
+  ], 400);
+
+  // Compute slope at midpoint of each machine's range
+  const slopes = {};
+  for (const [id, m] of Object.entries(machines)) {
+    const mid = (m.predictFlow.currentFxyYMin + m.predictFlow.currentFxyYMax) / 2;
+    const delta = (m.predictFlow.currentFxyYMax - m.predictFlow.currentFxyYMin) * 0.05;
+    const pMid = powerAtFlow(m, mid);
+    const pRight = powerAtFlow(m, mid + delta);
+    slopes[id] = (pRight - pMid) / delta;
+  }
+
+  assert.ok(slopes['flat'] > 0 && slopes['steep'] > 0, 'Both slopes should be positive');
+  assert.ok(
+    slopes['steep'] > slopes['flat'] * 1.3,
+    `Steep pump should have notably higher slope. flat=${slopes['flat'].toFixed(0)}, steep=${slopes['steep'].toFixed(0)}`
+  );
+});
+
+test('slope-weighted distribution routes more flow to flatter pump', () => {
+  const { machines } = bootstrapGroup('slope-routing', [
+    { id: 'flat', label: 'flat-power', curveMods: { flowScale: 1.2, powerScale: 0.7 } },
+    { id: 'steep', label: 'steep-power', curveMods: { flowScale: 0.8, powerScale: 1.4 } },
+  ], 400);
+
+  const totalMax = machines['flat'].predictFlow.currentFxyYMax + machines['steep'].predictFlow.currentFxyYMax;
+  const Qd = totalMax * 0.5;
+
+  const slopeResult = distributeBySlopeWeight(machines, Qd);
+
+  assert.ok(
+    slopeResult.distribution['flat'] > slopeResult.distribution['steep'],
+    `Flat pump should get more flow. flat=${slopeResult.distribution['flat'].toFixed(2)}, steep=${slopeResult.distribution['steep'].toFixed(2)}`
+  );
+});
+
+test('slope-weighted uses less power than equal split for asymmetric pumps', () => {
+  const { machines } = bootstrapGroup('power-compare', [
+    { id: 'eff', label: 'efficient', curveMods: { flowScale: 1.2, powerScale: 0.7, flowTilt: 0.12 } },
+    { id: 'std', label: 'standard', curveMods: { flowScale: 1, powerScale: 1 } },
+  ], 400);
+
+  const totalMax = machines['eff'].predictFlow.currentFxyYMax + machines['std'].predictFlow.currentFxyYMax;
+  const demandLevels = [0.3, 0.5, 0.7].map(p => {
+    const min = Math.max(machines['eff'].predictFlow.currentFxyYMin, machines['std'].predictFlow.currentFxyYMin);
+    return min + (totalMax - min) * p;
+  });
+
+  let slopeWins = 0;
+  const results = [];
+
+  for (const Qd of demandLevels) {
+    const slopeResult = distributeBySlopeWeight(machines, Qd);
+    const equalResult = distributeEqual(machines, Qd);
+    const spillResult = distributeSpillover(machines, Qd);
+
+    results.push({
+      demand: Qd,
+      slopePower: slopeResult.totalPower,
+      equalPower: equalResult.totalPower,
+      spillPower: spillResult.totalPower,
+    });
+
+    if (slopeResult.totalPower <= equalResult.totalPower + 1) slopeWins++;
+  }
+
+  assert.ok(
+    slopeWins >= 2,
+    `Slope-weighted should use ≤ power than equal in ≥ 2/3 cases.\n` +
+    results.map(r =>
+      `  Qd=${r.demand.toFixed(1)}: slope=${r.slopePower.toFixed(1)}W, equal=${r.equalPower.toFixed(1)}W, spill=${r.spillPower.toFixed(1)}W`
+    ).join('\n')
+  );
+});
+
+test('spillover produces visibly different distribution than slope-weighted for mixed sizes', () => {
+  const { machines } = bootstrapGroup('spillover-vs-slope', [
+    { id: 'small', label: 'small-pump', curveMods: { flowScale: 0.6, powerScale: 0.55 } },
+    { id: 'large', label: 'large-pump', curveMods: { flowScale: 1.5, powerScale: 1.2 } },
+  ], 400);
+
+  const totalMax = machines['small'].predictFlow.currentFxyYMax + machines['large'].predictFlow.currentFxyYMax;
+  const Qd = totalMax * 0.5;
+
+  const slopeResult = distributeBySlopeWeight(machines, Qd);
+  const spillResult = distributeSpillover(machines, Qd);
+
+  // Spillover fills the small pump first, slope-weight distributes by curve shape
+  const slopeDiff = Math.abs(slopeResult.distribution['small'] - spillResult.distribution['small']);
+  const percentDiff = (slopeDiff / Qd) * 100;
+
+  assert.ok(
+    percentDiff > 1,
+    `Strategies should produce different distributions. ` +
+    `Slope small=${slopeResult.distribution['small'].toFixed(2)}, ` +
+    `Spill small=${spillResult.distribution['small'].toFixed(2)} (${percentDiff.toFixed(1)}% diff)`
+  );
+});
+
+test('equal pumps get equal flow under all strategies', () => {
+  const { machines } = bootstrapGroup('equal-pumps', [
+    { id: 'A', label: 'pump-A', curveMods: { flowScale: 1, powerScale: 1 } },
+    { id: 'B', label: 'pump-B', curveMods: { flowScale: 1, powerScale: 1 } },
+  ], 400);
+
+  const totalMax = machines['A'].predictFlow.currentFxyYMax + machines['B'].predictFlow.currentFxyYMax;
+  const Qd = totalMax * 0.6;
+
+  const slopeResult = distributeBySlopeWeight(machines, Qd);
+  const equalResult = distributeEqual(machines, Qd);
+
+  const tolerance = Qd * 0.01;
+
+  assert.ok(
+    Math.abs(slopeResult.distribution['A'] - slopeResult.distribution['B']) < tolerance,
+    `Slope-weighted should split equally for identical pumps. A=${slopeResult.distribution['A'].toFixed(2)}, B=${slopeResult.distribution['B'].toFixed(2)}`
+  );
+  assert.ok(
+    Math.abs(equalResult.distribution['A'] - equalResult.distribution['B']) < tolerance,
+    `Equal should split equally. A=${equalResult.distribution['A'].toFixed(2)}, B=${equalResult.distribution['B'].toFixed(2)}`
+  );
+
+  // Power should be identical too
+  assert.ok(
+    Math.abs(slopeResult.totalPower - equalResult.totalPower) < 1,
+    `Equal pumps should produce same total power under any strategy`
+  );
+});
+
+test('full MGC optimalControl uses ≤ power than priorityControl for mixed pumps', async () => {
+  const { mg, machines } = bootstrapGroup('mgc-full', [
+    { id: 'eff', label: 'efficient', curveMods: { flowScale: 1.2, powerScale: 0.7, flowTilt: 0.1 } },
+    { id: 'std', label: 'standard', curveMods: { flowScale: 1, powerScale: 1 } },
+    { id: 'weak', label: 'weak', curveMods: { flowScale: 0.8, powerScale: 1.3, flowTilt: -0.08 } },
+  ], 400);
+
+  for (const m of Object.values(machines)) {
+    await m.handleInput('parent', 'execSequence', 'startup');
+  }
+
+  // Run optimalControl
+  mg.setMode('optimalcontrol');
+  mg.setScaling('normalized');
+  await mg.handleInput('parent', 50, Infinity);
+  const optPower = mg.measurements.type('power').variant('predicted').position('atequipment').getCurrentValue() || 0;
+  const optFlow = mg.measurements.type('flow').variant('predicted').position('atequipment').getCurrentValue() || 0;
+
+  // Reset machines
+  for (const m of Object.values(machines)) {
+    await m.handleInput('parent', 'execSequence', 'shutdown');
+    await m.handleInput('parent', 'execSequence', 'startup');
+  }
+
+  // Run priorityControl
+  mg.setMode('prioritycontrol');
+  await mg.handleInput('parent', 50, Infinity, ['eff', 'std', 'weak']);
+  const prioPower = mg.measurements.type('power').variant('predicted').position('atequipment').getCurrentValue() || 0;
+  const prioFlow = mg.measurements.type('flow').variant('predicted').position('atequipment').getCurrentValue() || 0;
+
+  assert.ok(optFlow > 0, `Optimal should deliver flow, got ${optFlow}`);
+  assert.ok(prioFlow > 0, `Priority should deliver flow, got ${prioFlow}`);
+
+  // Compare efficiency (flow per unit power)
+  const optEff = optPower > 0 ? optFlow / optPower : 0;
+  const prioEff = prioPower > 0 ? prioFlow / prioPower : 0;
+
+  assert.ok(
+    optEff >= prioEff * 0.95,
+    `Optimal efficiency should be ≥ priority (within 5% tolerance). ` +
+    `Opt: ${optFlow.toFixed(1)}/${optPower.toFixed(1)}=${optEff.toFixed(6)} | ` +
+    `Prio: ${prioFlow.toFixed(1)}/${prioPower.toFixed(1)}=${prioEff.toFixed(6)}`
+  );
+});

test/integration/structure-examples.integration.test.js

@@ -0,0 +1,23 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const dir = path.resolve(__dirname, '../../examples');
+
+function loadJson(file) {
+  return JSON.parse(fs.readFileSync(path.join(dir, file), 'utf8'));
+}
+
+test('examples package exists for machineGroupControl', () => {
+  for (const file of ['README.md', 'basic.flow.json', 'integration.flow.json', 'edge.flow.json']) {
+    assert.equal(fs.existsSync(path.join(dir, file)), true, file + ' missing');
+  }
+});
+
+test('example flows are parseable arrays for machineGroupControl', () => {
+  for (const file of ['basic.flow.json', 'integration.flow.json', 'edge.flow.json']) {
+    const parsed = loadJson(file);
+    assert.equal(Array.isArray(parsed), true);
+  }
+});