updates

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

@@ -39,7 +39,7 @@
         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/nodeClass.js

@@ -1,4 +1,4 @@
-const { outputUtils, configManager } = require("generalFunctions");
+const { outputUtils, configManager, convert } = require("generalFunctions");
 const Specific = require("./specificClass");
 
 class nodeClass {
@@ -37,13 +37,14 @@ 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');
 
     // Merge UI config over defaults
     this.config = {
       general: {
         name: uiConfig.name,
         id: node.id, // node.id is for the child registration process
-        unit: uiConfig.unit, // add converter options later to convert to default units (need like a model that defines this which units we are going to use and then conver to those standards)
+        unit: flowUnit,
         logging: {
           enabled: uiConfig.enableLog,
           logLevel: uiConfig.logLevel,
@@ -57,6 +58,24 @@ 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;
@@ -68,19 +87,19 @@ class nodeClass {
       ?.type("flow")
       ?.variant("predicted")
       ?.position("atequipment")
-      ?.getCurrentValue('m3/h') || 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') {
-        console.warn(`Machine missing or invalid:`, machine?.config?.general?.id || 'unknown');
+        mg.logger?.warn(`Machine missing or invalid: ${machine?.config?.general?.id || 'unknown'}`);
         return false;
       }
       
@@ -195,67 +214,52 @@ class nodeClass {
     this.node.on(
       "input",
       async (msg, send, done) => {
-            const mg = this.source;
-            const RED = this.RED;
+        const mg = this.source;
+        const RED = this.RED;
+        try {
           switch (msg.topic) {
-            case "registerChild":
-                    //console.log(`Registering child in mgc: ${msg.payload}`);
-                    const childId = msg.payload;
-                    const childObj = RED.nodes.getNode(childId);
-                    
-                    // Debug: Check what we're getting
-                    //console.log(`Child object:`, childObj ? 'found' : 'NOT FOUND');
-                    //console.log(`Child source:`, childObj?.source ? 'exists' : 'MISSING');
-                    if (childObj?.source) {
-                      //console.log(`Child source type:`, childObj.source.constructor.name);
-                      //console.log(`Child has state:`, !!childObj.source.state);
-                    }
-                    
-                    mg.childRegistrationUtils.registerChild(
-                      childObj.source,
-                      msg.positionVsParent
-                    );
-                    
-                    // Debug: Check machines after registration
-                    //console.log(`Total machines after registration:`, Object.keys(mg.machines || {}).length);
-                    break;
-
+            case "registerChild": {
+              const childId = msg.payload;
+              const childObj = RED.nodes.getNode(childId);
+              if (!childObj || !childObj.source) {
+                mg.logger.warn(`registerChild skipped: missing child/source for id=${childId}`);
+                break;
+              }
+              mg.childRegistrationUtils.registerChild(childObj.source, msg.positionVsParent);
+              break;
+            }
             case "setMode":
-              const mode = msg.payload;
-              mg.setMode(mode);
+              mg.setMode(msg.payload);
               break;
-
             case "setScaling":
-              const scaling = msg.payload;
-              mg.setScaling(scaling);
-
+              mg.setScaling(msg.payload);
               break;
-
-            case "Qd":
+            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) {
-                console.log(e);
+              } catch (error) {
+                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();
+      }
     );
   }
 
@@ -266,7 +270,7 @@ 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} = require('generalFunctions');
+const {logger,configUtils,configManager, MeasurementContainer, interpolation , childRegistrationUtils, convert} = 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 = {}) {
 
@@ -10,20 +28,37 @@ 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({
-        autoConvert: true,
-        windowSize: 50,
-        defaultUnits: {
-            pressure: 'mbar',
-            flow: 'l/s',
-            power: 'kW',
-            temperature: 'C'
-        }
+            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();
@@ -50,7 +85,8 @@ class MachineGroup {
     registerChild(child,softwareType) {
         this.logger.debug('Setting up childs specific for this class');
 
-        const position = child.config.general.positionVsParent;
+        // 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
@@ -160,8 +196,8 @@ class MachineGroup {
             const minPower = machine.predictPower.currentFxyYMin;
             const maxPower = machine.predictPower.currentFxyYMax;
 
-            const actFlow = machine.measurements.type("flow").variant("predicted").position("atequipment").getCurrentValue();
-            const actPower = machine.measurements.type("power").variant("predicted").position("atequipment").getCurrentValue();
+            const actFlow = this._readChildMeasurement(machine, "flow", "predicted", "atequipment", this.unitPolicy.canonical.flow) || 0;
+            const actPower = this._readChildMeasurement(machine, "power", "predicted", "atequipment", 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}`);
 
@@ -210,13 +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("atequipment").value(flow.act);
-        this.measurements.type("power").variant("predicted").position("atequipment").value(power.act);
+        this._writeMeasurement("flow", "predicted", "atequipment", flow.act, this.unitPolicy.canonical.flow);
+        this._writeMeasurement("power", "predicted", "atequipment", power.act, this.unitPolicy.canonical.power);
 
         const { maxEfficiency, lowestEfficiency } = this.calcGroupEfficiency(this.machines);
         const efficiency = this.measurements.type("efficiency").variant("predicted").position("atequipment").getCurrentValue();
@@ -255,11 +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("downstream").getCurrentValue()){
-                    flow = machine.measurements.type("flow").variant("measured").position("downstream").getCurrentValue();
+                const measuredFlow = this._readChildMeasurement(machine, "flow", "measured", "downstream", this.unitPolicy.canonical.flow);
+                const predictedFlow = this._readChildMeasurement(machine, "flow", "predicted", "atequipment", this.unitPolicy.canonical.flow);
+                if (Number.isFinite(measuredFlow) && measuredFlow !== 0) {
+                    flow = measuredFlow;
                 } 
-                else if(machine.measurements.type("flow").variant("predicted").position("atequipment").getCurrentValue()){
-                    flow = machine.measurements.type("flow").variant("predicted").position("atequipment").getCurrentValue();
+                else if (Number.isFinite(predictedFlow) && predictedFlow !== 0) {
+                    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");
@@ -611,8 +649,8 @@ class MachineGroup {
             // 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("downstream").getCurrentValue(),
-                    upstream: machine.measurements.type("pressure").variant("measured").position("upstream").getCurrentValue()
+                    downstream: this._readChildMeasurement(machine, "pressure", "measured", "downstream", this.unitPolicy.canonical.pressure),
+                    upstream: this._readChildMeasurement(machine, "pressure", "measured", "upstream", this.unitPolicy.canonical.pressure)
                 };
             });
 
@@ -626,8 +664,8 @@ 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("downstream").value(maxDownstream);
-                    machine.measurements.type("pressure").variant("measured").position("upstream").value(minUpstream);
+                    this._writeChildMeasurement(machine, "pressure", "measured", "downstream", maxDownstream, this.unitPolicy.canonical.pressure);
+                    this._writeChildMeasurement(machine, "pressure", "measured", "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
@@ -690,8 +728,8 @@ 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("atequipment").value(bestResult.bestPower);
-            this.measurements.type("flow").variant("predicted").position("atequipment").value(bestResult.bestFlow);
+            this._writeMeasurement("power", "predicted", "atequipment", bestResult.bestPower, this.unitPolicy.canonical.power);
+            this._writeMeasurement("flow", "predicted", "atequipment", bestResult.bestFlow, this.unitPolicy.canonical.flow);
             this.measurements.type("efficiency").variant("predicted").position("atequipment").value(bestResult.bestFlow / bestResult.bestPower);
             this.measurements.type("Ncog").variant("predicted").position("atequipment").value(bestResult.bestCog);
 
@@ -731,8 +769,8 @@ class MachineGroup {
         // Get current pressures from all machines
         const pressures = Object.entries(this.machines).map(([machineId, machine]) => {
             return { 
-                downstream: machine.measurements.type("pressure").variant("measured").position("downstream").getCurrentValue(),
-                upstream: machine.measurements.type("pressure").variant("measured").position("upstream").getCurrentValue()
+                downstream: this._readChildMeasurement(machine, "pressure", "measured", "downstream", this.unitPolicy.canonical.pressure),
+                upstream: this._readChildMeasurement(machine, "pressure", "measured", "upstream", this.unitPolicy.canonical.pressure)
             };
         });
     
@@ -743,8 +781,8 @@ 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("downstream").value(maxDownstream);
-                machine.measurements.type("pressure").variant("measured").position("upstream").value(minUpstream);
+                this._writeChildMeasurement(machine, "pressure", "measured", "downstream", maxDownstream, this.unitPolicy.canonical.pressure);
+                this._writeChildMeasurement(machine, "pressure", "measured", "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}`);
@@ -920,8 +958,8 @@ 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("atequipment").value(totalPower);
-            this.measurements.type("flow").variant("predicted").position("atequipment").value(totalFlow);
+            this._writeMeasurement("power", "predicted", "atequipment", totalPower, this.unitPolicy.canonical.power);
+            this._writeMeasurement("flow", "predicted", "atequipment", totalFlow, this.unitPolicy.canonical.flow);
             this.measurements.type("efficiency").variant("predicted").position("atequipment").value(totalFlow / totalPower);
             this.measurements.type("Ncog").variant("predicted").position("atequipment").value(totalCog);
 
@@ -1035,8 +1073,8 @@ class MachineGroup {
             // fetch and store measurements
             Object.entries(this.machines).forEach(([machineId, machine]) => {
 
-                const powerValue = machine.measurements.type("power").variant("predicted").position("atequipment").getCurrentValue();
-                const flowValue = machine.measurements.type("flow").variant("predicted").position("atequipment").getCurrentValue();
+                const powerValue = this._readChildMeasurement(machine, "power", "predicted", "atequipment", this.unitPolicy.canonical.power);
+                const flowValue = this._readChildMeasurement(machine, "flow", "predicted", "atequipment", this.unitPolicy.canonical.flow);
 
                 if (powerValue !== null) {
                     totalPower.push(powerValue);
@@ -1046,8 +1084,8 @@ class MachineGroup {
                 }
             });
 
-            this.measurements.type("power").variant("predicted").position("atequipment").value(totalPower.reduce((a, b) => a + b, 0));
-            this.measurements.type("flow").variant("predicted").position("atequipment").value(totalFlow.reduce((a, b) => a + b, 0));
+            this._writeMeasurement("power", "predicted", "atequipment", totalPower.reduce((a, b) => a + b, 0), this.unitPolicy.canonical.power);
+            this._writeMeasurement("flow", "predicted", "atequipment", 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("atequipment").value(totalFlow.reduce((a, b) => a + b, 0) / totalPower.reduce((a, b) => a + b, 0));
@@ -1158,6 +1196,106 @@ class MachineGroup {
         }));
     }
 
+    _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;
+        }
+    }
+
+    _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;
     }
@@ -1168,27 +1306,32 @@ class MachineGroup {
         const output = {};
 
         //build the output object
-        this.measurements.getTypes().forEach(type => {
-          this.measurements.getVariants(type).forEach(variant => {
+        Object.entries(this.measurements.measurements || {}).forEach(([type, variants]) => {
+            Object.keys(variants || {}).forEach((variant) => {
+                const unit = this._outputUnitForType(type);
+                const downstreamVal = this._readMeasurement(type, variant, "downstream", unit);
+                const atEquipmentVal = this._readMeasurement(type, variant, "atequipment", unit);
+                const upstreamVal = this._readMeasurement(type, variant, "upstream", unit);
 
-            const downstreamVal = this.measurements.type(type).variant(variant).position("downstream").getCurrentValue();
-            const atEquipmentVal = this.measurements.type(type).variant(variant).position("atequipment").getCurrentValue();
-            const upstreamVal = this.measurements.type(type).variant(variant).position("upstream").getCurrentValue();
-    
-            if (downstreamVal != null) {
-              output[`downstream_${variant}_${type}`] = downstreamVal;
-            }
-            if (upstreamVal != null) {
-              output[`upstream_${variant}_${type}`] = upstreamVal;
-            }
-            if (atEquipmentVal != null) {
-              output[`atequipment${variant}_${type}`] = atEquipmentVal;
-            }
-            if (downstreamVal != null && upstreamVal != null) {
-              const diffVal = this.measurements.type(type).variant(variant).difference().value;
-              output[`differential_${variant}_${type}`] = diffVal;
-            }
-          });
+                if (downstreamVal != null) {
+                    output[`downstream_${variant}_${type}`] = downstreamVal;
+                }
+                if (upstreamVal != null) {
+                    output[`upstream_${variant}_${type}`] = upstreamVal;
+                }
+                if (atEquipmentVal != null) {
+                    output[`atequipment${variant}_${type}`] = atEquipmentVal;
+                }
+                if (downstreamVal != null && upstreamVal != null) {
+                    const diff = this.measurements
+                        .type(type)
+                        .variant(variant)
+                        .difference({ from: 'downstream', to: 'upstream', unit });
+                    if (diff?.value != null) {
+                        output[`differential_${variant}_${type}`] = diff.value;
+                    }
+                }
+            });
         });
     
         //fill in the rest of the output object
@@ -1396,6 +1539,8 @@ 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/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);
+  }
+});