EVOLV/wiki/sessions/2026-04-13-measurement-digital-mode.md

title, created, updated, status, tags

title	created	updated	status	tags
Session: measurement node — dispatcher bug fix + digital/MQTT mode	2026-04-13	2026-04-13	proven	session measurement smoothing outlier mqtt iot

2026-04-13 — measurement trial-ready + digital mode

Scope

Honest review of the measurement node. Benchmark every method, reason about keeping the node agnostic across analog and digital sources, add a digital (MQTT/IoT) mode without breaking analog.

Findings

Silent dispatcher bug (critical)

validateEnum in generalFunctions lowercases enum values (zScore → zscore, lowPass → lowpass). But specificClass.outlierDetection and specificClass.applySmoothing compared against camelCase keys. Effect:

• 5 of 11 smoothing methods silently fell through to a no-op: lowPass, highPass, weightedMovingAverage, bandPass, savitzkyGolay.
• 2 of 3 outlier methods silently disabled: zScore, modifiedZScore.
• Only mean, median, sd, min, max, none, kalman, iqr (the already-lowercase ones) actually worked.

Users who picked any camelCase method from the dropdown got the raw last value or no outlier filtering, with no error. Flows deployed before this session that relied on these filters got no filtering at all.

Test coverage was thin

Pre-session: 12 tests — 1 for scaling, 1 for outlier toggle, 1 for event emit, 3 for example flow shape, 1 constructor, 1 routing, 1 invalid payload, 2 other. Every smoothing method beyond mean and every outlier method beyond a toggle-flip was untested. The dispatcher bug would have been caught immediately by per-method unit tests.

Analog-only input shape

The node only accepted scalar msg.payload. MQTT / IoT devices commonly publish a single JSON blob with many readings per message. Every user wanting that pattern had to fan out into N measurement nodes — ugly, and the device's shared timestamp is lost.

Fixes + additions

Dispatcher normalization (specificClass.js)

Both outlierDetection() and applySmoothing() now lowercase the configured method and the lookup table keys. Legacy camelCase config values and normalized lowercase config values both work.

MeasurementContainer.isUnitCompatible permissive short-circuit

Previously: if the unit couldn't be described by the convert module, compatibility returned false regardless of type. This blocked user-defined types like humidity with unit %. Now: when measureMap[type] is undefined (unknown type), accept any unit. Known types still validate strictly.

Digital mode (new)

config.mode.current === 'digital' opts into a new input shape. config.channels declares one entry per JSON key. The new Channel class (src/channel.js) is a self-contained per-channel pipeline — outlier → offset → scaling → smoothing → min/max → constrain → emit. Analog behaviour is preserved exactly; flows built before this session work unchanged.

Test additions

Before → after: 12 → 71 tests.

New files:

• test/basic/smoothing-methods.basic.test.js — every smoothing method covered, 16 tests.
• test/basic/outlier-detection.basic.test.js — every outlier method + toggle + fall-through, 10 tests.
• test/basic/scaling-and-interpolation.basic.test.js — offset / interpolateLinear / constrain / handleScaling / updateMinMaxValues / updateOutputPercent / updateOutputAbs / getOutput, 10 tests.
• test/basic/calibration-and-stability.basic.test.js — calibrate / isStable / evaluateRepeatability / toggleSimulation / tick / simulateInput, 11 tests.
• test/integration/digital-mode.integration.test.js — 12 tests covering channel build, payload dispatch, multi-channel emit, unknown keys, per-channel scaling / smoothing / outlier, empty channels, malformed entries, non-numeric values, digital-output shape.

E2E verification (Dockerized Node-RED)

Analog baseline — /tmp/m_e2e_baseline.py

Deploys examples/basic.flow.json, fires {topic:"measurement", payload:42} repeatedly. Observed port-0 output: mAbs climbed 0 → 2.1 → 2.8 → 3.15 → 3.36 → 4.2 across five ticks as the mean window filled with 42s (scaling 0..100 → 0..10). Tick cadence 909–1001 ms (avg 981 ms). Registration at t=0.22 s.

Digital end-to-end — /tmp/m_digital_e2e.py

Deploys a single measurement node in digital mode with three channels (temperature / humidity / pressure) and fires two MQTT-shaped payloads.

Tick	Channel	mAbs	totalMinSmooth	totalMaxSmooth
after inject 1	temperature	22.5	22.5	22.5
after inject 1	humidity	45	45	45
after inject 1	pressure	1013	1013	1013
after inject 2	temperature	24	22.5	24
after inject 2	humidity	42.5	42.5	45
after inject 2	pressure	1014	1013	1014

Mean smoothing across a window of 3 computed per-channel, the unknown key in the payload ignored, all three events emitted on <type>.measured.atequipment.

Files changed

nodes/generalFunctions/src/measurements/MeasurementContainer.js   # permissive unit check for user-defined types
nodes/generalFunctions/src/configs/measurement.json               # mode + channels schema

nodes/measurement/src/channel.js                                   # new per-channel pipeline class
nodes/measurement/src/specificClass.js                             # dispatcher fix + digital dispatch
nodes/measurement/src/nodeClass.js                                 # mode-aware input handler + tick
nodes/measurement/measurement.html                                 # Mode dropdown + Channels JSON + help panel
nodes/measurement/README.md                                        # rewrite

nodes/measurement/test/basic/smoothing-methods.basic.test.js       # +16 tests
nodes/measurement/test/basic/outlier-detection.basic.test.js       # +10 tests
nodes/measurement/test/basic/scaling-and-interpolation.basic.test.js # +10 tests
nodes/measurement/test/basic/calibration-and-stability.basic.test.js # +11 tests
nodes/measurement/test/integration/digital-mode.integration.test.js  # +12 tests

Production status

Trial-ready for both modes. Supervised trial recommended for digital-mode deployments until the channels-editor UI (currently a JSON textarea) lands.

Follow-ups

• Repeatable-row editor widget for channels.
• validateArray.minLength=0 evaluates as falsy; pre-existing generalFunctions bug affecting this node's channels and also measurement.assetRegistration.childAssets. Harmless warn at deploy time.
• Per-channel calibration + simulation for digital mode.
• Runtime channel reconfiguration via a dedicated topic (addChannel / removeChannel).