fix(ps): persist stopLevel/holdLevel as numbers across editor save

Node-RED's auto-form-binding writes <input type="number"> values into the
node object as strings. The editor's setNumberField helper used strict
Number.isFinite(val) which rejects "0.5" and blanked the input on reopen,
so users saw their stopLevel/holdLevel values disappear after clicking Done.

- oneditsave: explicitly parseFloat stopLevel, holdLevel, and
  deadZoneKeepAlivePercent so they land in the node as numbers (matches the
  treatment of startLevel/maxLevel).
- oneditprepare: parseFloat node.holdLevel / node.deadZoneKeepAlivePercent
  before the Number.isFinite check so existing string-typed flows still
  render their saved values.
- index.js setNumberField: defensively coerce stringy numbers so this
  gotcha can't bite a future field.

Verified end-to-end in headless Chromium: type new values, click Done,
reopen — values persist and the stopLevel/holdLevel marker lines render
at the correct x in the level-based mode preview.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,10 @@
+# Repo dev artifacts. Mirrors the deny list in .npmignore so the two stay
+# in sync — anything that shouldn't be committed AND shouldn't ship in the
+# npm tarball goes in both files.
+node_modules/
+package-lock.json
+*.tgz
+.env
+.env.*
+.DS_Store
+npm-debug.log*

.npmignore

@@ -0,0 +1,31 @@
+# === Mirrors .gitignore — items below this block are also excluded from
+#     the npm tarball. Kept here verbatim so npm pack doesn't fall back to
+#     the .gitignore inheritance (silent + surprising). ===
+node_modules/
+package-lock.json
+*.tgz
+.env
+.env.*
+.DS_Store
+npm-debug.log*
+
+# === Dev-only content the npm tarball doesn't need ===
+# Tests + their harness — Node-RED loads the entry .js, not the test tree.
+test/
+*.test.js
+
+# Wiki, screenshots, drawio diagrams — useful in the repo, big in the pack.
+wiki/
+
+# Local simulation harness + scenario data (dev-only). 870+ KB on disk.
+simulations/
+
+# Build/maintenance tooling not used at runtime.
+tools/
+
+# Project memory + IDE configs.
+.claude/
+.codex/
+.repo-mem/
+CLAUDE.md
+CLAUDE.local.md

CLAUDE.md

@@ -21,3 +21,20 @@ Key points for this node:
 - 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 `#0c99d9` (Process Cell).
+
+## Folder & File Layout
+
+Every per-node file MUST use the folder name (`pumpingStation`) **exactly**, case-sensitive. Full rule: [`.claude/rules/node-architecture.md`](https://gitea.wbd-rd.nl/RnD/EVOLV/src/branch/development/.claude/rules/node-architecture.md) in the EVOLV superproject.
+
+| Path | Required name |
+|---|---|
+| Entry file | `pumpingStation.js` |
+| Editor HTML | `pumpingStation.html` |
+| Node adapter | `src/nodeClass.js` |
+| Domain logic | `src/specificClass.js` |
+| Editor JS modules | `src/editor/*.js` (extract when inline editor JS exceeds ~50 lines) |
+| Tests | `test/{basic,integration,edge}/*.test.js` |
+| Example flows | `examples/*.flow.json` |
+
+
+When adding new files, read the rule above first to avoid drift.

CONTRACT.md

@@ -12,6 +12,7 @@ Hand-maintained for Phase 2; the `## Inputs` table is generated from
 | `cmd.calibrate.volume` | `calibratePredictedVolume` | numeric (number or numeric string) — m³ | Resets the predicted-volume series and seeds it with the supplied value; recomputes level. |
 | `cmd.calibrate.level` | `calibratePredictedLevel` | numeric — metres | Resets the predicted-level series and seeds it with the supplied value; recomputes volume. |
 | `set.inflow` | `q_in` | number, numeric string, or `{ value, unit, timestamp }` | Pushes a manual inflow measurement onto the predicted-flow series. `unit` may be on the message (`msg.unit`) or inside the object payload. |
+| `set.outflow` | `q_out` | number, numeric string, or `{ value, unit, timestamp }` | Pushes a measured outflow value into the basin balance. Same payload conventions as `set.inflow`. |
 | `set.demand` | `Qd` | numeric — child setpoint demand | Forwards the demand to direct children (machineGroups / machines / stations). Only honoured in `manual` mode; in other modes the call is logged at `debug` and discarded. |
 
 Aliases log a one-time deprecation warning the first time they fire.

examples/02-Dashboard.json

@@ -166,8 +166,8 @@
         "id": "b30af582f935bcb7",
         "type": "comment",
         "z": "77f00aef1c966167",
-        "name": "PumpingStation — Dashboard (Tier 2)",
+        "name": "PumpingStation \u2014 Dashboard (Tier 2)",
-        "info": "Same command surface as the Basic example, driven by a FlowFuse dashboard.\n\nOpen /dashboard/pumpingstation-basic after deploy.\n\nCONTROLS panel\n- Mode buttons → set.mode (manual / levelbased)\n- Inflow / Outflow buttons → set.inflow / set.outflow (60 / 80 m³/h)\n- Demand button → set.demand (40 m³/h, manual mode only)\n- Calibrate buttons → cmd.calibrate.volume / cmd.calibrate.level\n\nSTATUS panel\n- 7 text rows: Mode, Direction, Level, Volume, Volume %, percControl, Manual demand\n\nTRENDS panel\n- 4 charts: Level (m), Volume (m³), Volume %, Flow (in/out/net m³/h)\n\nRAW OUTPUT panel\n- Full key/value dump of the latest Port 0 cache (sorted). Shows every field the node emits including basin geometry, safety thresholds, predicted overflow/underflow.\n\nThe fan-out function caches last-known values so delta-only Port 0 updates never blank a row.",
+        "info": "Same command surface as the Basic example, driven by a FlowFuse dashboard.\n\nOpen /dashboard/pumpingstation-basic after deploy.\n\nCONTROLS panel\n- Mode buttons \u2192 set.mode (manual / levelbased)\n- Inflow / Outflow buttons \u2192 set.inflow / set.outflow (60 / 80 m\u00b3/h)\n- Demand button \u2192 set.demand (40 m\u00b3/h, manual mode only)\n- Calibrate buttons \u2192 cmd.calibrate.volume / cmd.calibrate.level\n\nSTATUS panel\n- 7 text rows: Mode, Direction, Level, Volume, Volume %, percControl, Manual demand\n\nTRENDS panel\n- 4 charts: Level (m), Volume (m\u00b3), Volume %, Flow (in/out/net m\u00b3/h)\n\nRAW OUTPUT panel\n- Full key/value dump of the latest Port 0 cache (sorted). Shows every field the node emits including basin geometry, safety thresholds, predicted overflow/underflow.\n\nThe fan-out function caches last-known values so delta-only Port 0 updates never blank a row.",
         "x": 660,
         "y": 320,
         "wires": []
@@ -332,13 +332,13 @@
         "z": "77f00aef1c966167",
         "g": "a9f9b38b0e00c1d7",
         "group": "ui_group_ctrl",
-        "name": "Inflow 60 m³/h",
+        "name": "Inflow 60 m\u00b3/h",
-        "label": "Inflow 60 m³/h",
+        "label": "Inflow 60 m\u00b3/h",
         "order": 3,
         "width": "3",
         "height": "1",
         "emulateClick": false,
-        "tooltip": "Push a measured inflow of 60 m³/h into the basin balance",
+        "tooltip": "Push a measured inflow of 60 m\u00b3/h into the basin balance",
         "color": "",
         "bgcolor": "",
         "icon": "south",
@@ -360,13 +360,13 @@
         "z": "77f00aef1c966167",
         "g": "a9f9b38b0e00c1d7",
         "group": "ui_group_ctrl",
-        "name": "Outflow 80 m³/h",
+        "name": "Outflow 80 m\u00b3/h",
-        "label": "Outflow 80 m³/h",
+        "label": "Outflow 80 m\u00b3/h",
         "order": 4,
         "width": "3",
         "height": "1",
         "emulateClick": false,
-        "tooltip": "Push a measured outflow of 80 m³/h into the basin balance",
+        "tooltip": "Push a measured outflow of 80 m\u00b3/h into the basin balance",
         "color": "",
         "bgcolor": "",
         "icon": "north",
@@ -388,13 +388,13 @@
         "z": "77f00aef1c966167",
         "g": "42bf82c87d05f498",
         "group": "ui_group_ctrl",
-        "name": "Demand 40 m³/h",
+        "name": "Demand 40 m\u00b3/h",
-        "label": "Demand 40 m³/h (manual)",
+        "label": "Demand 40 m\u00b3/h (manual)",
         "order": 5,
         "width": "6",
         "height": "1",
         "emulateClick": false,
-        "tooltip": "Operator outflow demand — only forwarded when mode = manual",
+        "tooltip": "Operator outflow demand \u2014 only forwarded when mode = manual",
         "color": "",
         "bgcolor": "",
         "icon": "speed",
@@ -416,13 +416,13 @@
         "z": "77f00aef1c966167",
         "g": "234bdce20170061a",
         "group": "ui_group_ctrl",
-        "name": "Calibrate V=25 m³",
+        "name": "Calibrate V=25 m\u00b3",
-        "label": "Calibrate V = 25 m³",
+        "label": "Calibrate V = 25 m\u00b3",
         "order": 6,
         "width": "3",
         "height": "1",
         "emulateClick": false,
-        "tooltip": "Snap the predicted-volume integrator to 25 m³",
+        "tooltip": "Snap the predicted-volume integrator to 25 m\u00b3",
         "color": "",
         "bgcolor": "",
         "icon": "tune",
@@ -472,8 +472,8 @@
         "z": "77f00aef1c966167",
         "g": "grp_status_panel",
         "name": "fan-out Port 0 (status + charts + raw)",
-        "func": "// Port 0 emits delta-only — cache last-known so deltas never blank a row.\n// Keys with dots use the runtime childId (= node id), so we pattern-match\n// by prefix rather than hardcoding.\nconst cache = context.get('cache') || {};\nconst p = msg.payload || {};\nfor (const k in p) cache[k] = p[k];\ncontext.set('cache', cache);\n\nconst findByPrefix = (prefix) => {\n  for (const k of Object.keys(cache)) if (k.startsWith(prefix)) return cache[k];\n  return null;\n};\nconst num = (v, dp, unit) => {\n  const n = +v;\n  if (!Number.isFinite(n)) return '—';\n  return n.toFixed(dp) + (unit ? ' ' + unit : '');\n};\n\nconst level   = findByPrefix('level.predicted.atequipment.');\nconst volume  = findByPrefix('volume.predicted.atequipment.');\nconst volPct  = findByPrefix('volumePercent.predicted.atequipment.');\nconst qInS    = findByPrefix('flow.predicted.in.');\nconst qOutS   = findByPrefix('flow.predicted.out.');\nconst qNetS   = findByPrefix('netFlowRate.predicted.atequipment.');\nconst qInH    = Number.isFinite(+qInS)  ? +qInS  * 3600 : null;\nconst qOutH   = Number.isFinite(+qOutS) ? +qOutS * 3600 : null;\nconst qNetH   = Number.isFinite(+qNetS) ? +qNetS * 3600 : null;\nconst pct     = cache.percControl;\nconst dem     = cache.manualDemand;\nconst mode    = cache.mode || '—';\nconst dir     = cache.direction || '—';\n\nconst chart = (topic, v) => Number.isFinite(+v) ? { topic, payload: +v } : null;\n\n// Raw view: every cached key, sorted, with values prettified for display.\nconst rawRows = Object.keys(cache).sort().map((k) => {\n  const v = cache[k];\n  let display;\n  if (v === null || v === undefined) display = '—';\n  else if (typeof v === 'number')   display = Number.isInteger(v) ? String(v) : v.toFixed(4);\n  else                              display = String(v);\n  return { key: k, value: display };\n});\n\nreturn [\n  // 0–6: status text widgets\n  { payload: mode },\n  { payload: dir },\n  { payload: num(level,  2, 'm') },\n  { payload: num(volume, 2, 'm³') },\n  { payload: num(volPct, 2, '%') },\n  { payload: num(pct,    1, '%') },\n  { payload: mode === 'manual'\n      ? (Number.isFinite(+dem) ? num(dem, 1, 'm³/h') : 'not set')\n      : '—' },\n  // 7–9: single-series charts\n  chart('Level',    level),\n  chart('Volume',   volume),\n  chart('Volume %', volPct),\n  // 10–12: flow chart (three series share the same chart node)\n  chart('Inflow',   qInH),\n  chart('Outflow',  qOutH),\n  chart('Net',      qNetH),\n  // 13: raw key/value rows for the ui-template\n  { payload: rawRows },\n];\n",
+        "func": "// Port 0 emits delta-only \u2014 cache last-known so deltas never blank a row.\n// Keys with dots use the runtime childId (= node id), so we pattern-match\n// by prefix rather than hardcoding.\nconst cache = context.get('cache') || {};\nconst p = msg.payload || {};\nfor (const k in p) cache[k] = p[k];\ncontext.set('cache', cache);\n\nconst findByPrefix = (prefix) => {\n  for (const k of Object.keys(cache)) if (k.startsWith(prefix)) return cache[k];\n  return null;\n};\nconst num = (v, dp, unit) => {\n  const n = +v;\n  if (!Number.isFinite(n)) return '\u2014';\n  return n.toFixed(dp) + (unit ? ' ' + unit : '');\n};\n\nconst level   = findByPrefix('level.predicted.atequipment.');\nconst volume  = findByPrefix('volume.predicted.atequipment.');\nconst volPct  = findByPrefix('volumePercent.predicted.atequipment.');\nconst qInS    = findByPrefix('flow.predicted.in.');\nconst qOutS   = findByPrefix('flow.predicted.out.');\nconst qNetS   = findByPrefix('netFlowRate.predicted.atequipment.');\nconst qInH    = Number.isFinite(+qInS)  ? +qInS  * 3600 : null;\nconst qOutH   = Number.isFinite(+qOutS) ? +qOutS * 3600 : null;\nconst qNetH   = Number.isFinite(+qNetS) ? +qNetS * 3600 : null;\nconst pct     = cache.percControl;\nconst dem     = cache.manualDemand;\nconst mode    = cache.mode || '\u2014';\nconst dir     = cache.direction || '\u2014';\n\nconst chart = (topic, v) => Number.isFinite(+v) ? { topic, payload: +v } : null;\n\n// Raw view: every cached key, sorted, with values prettified for display.\nconst rawRows = Object.keys(cache).sort().map((k) => {\n  const v = cache[k];\n  let display;\n  if (v === null || v === undefined) display = '\u2014';\n  else if (typeof v === 'number')   display = Number.isInteger(v) ? String(v) : v.toFixed(4);\n  else                              display = String(v);\n  return { key: k, value: display };\n});\n\nreturn [\n  // 0\u20136: status text widgets\n  { payload: mode },\n  { payload: dir },\n  { payload: num(level,  2, 'm') },\n  { payload: num(volume, 2, 'm\u00b3') },\n  { payload: num(volPct, 2, '%') },\n  { payload: num(pct,    1, '%') },\n  { payload: mode === 'manual'\n      ? (Number.isFinite(+dem) ? num(dem, 1, 'm\u00b3/h') : 'not set')\n      : '\u2014' },\n  // 7\u20139: single-series charts\n  chart('Level',    level),\n  chart('Volume',   volume),\n  chart('Volume %', volPct),\n  // 10\u201312: flow chart (three series share the same chart node)\n  chart('Inflow',   qInH),\n  chart('Outflow',  qOutH),\n  chart('Net',      qNetH),\n  // 13: raw key/value rows for the ui-template\n  { payload: rawRows },\n  // 14: percControl chart\n  chart('percControl', pct),\n];\n",
-        "outputs": 14,
+        "outputs": 15,
         "timeout": 0,
         "noerr": 0,
         "initialize": "",
@@ -523,6 +523,9 @@
             ],
             [
                 "ui_tpl_raw"
+            ],
+            [
+                "ui_chart_pumping_perccontrol"
             ]
         ]
     },
@@ -740,8 +743,8 @@
         "z": "77f00aef1c966167",
         "g": "grp_status_panel",
         "group": "ui_group_trends",
-        "name": "Volume (m³)",
+        "name": "Volume (m\u00b3)",
-        "label": "Volume (m³)",
+        "label": "Volume (m\u00b3)",
         "order": 2,
         "width": 6,
         "height": 4,
@@ -754,7 +757,7 @@
         "xAxisPropertyType": "timestamp",
         "xAxisFormat": "",
         "xAxisFormatType": "auto",
-        "yAxisLabel": "m³",
+        "yAxisLabel": "m\u00b3",
         "yAxisProperty": "payload",
         "yAxisPropertyType": "msg",
         "xmin": "",
@@ -862,8 +865,8 @@
         "z": "77f00aef1c966167",
         "g": "grp_status_panel",
         "group": "ui_group_trends",
-        "name": "Flow (m³/h)",
+        "name": "Flow (m\u00b3/h)",
-        "label": "Flow (m³/h) — Inflow / Outflow / Net",
+        "label": "Flow (m\u00b3/h) \u2014 Inflow / Outflow / Net",
         "order": 4,
         "width": 6,
         "height": 4,
@@ -876,7 +879,7 @@
         "xAxisPropertyType": "timestamp",
         "xAxisFormat": "",
         "xAxisFormatType": "auto",
-        "yAxisLabel": "m³/h",
+        "yAxisLabel": "m\u00b3/h",
         "yAxisProperty": "payload",
         "yAxisPropertyType": "msg",
         "xmin": "",
@@ -1029,7 +1032,7 @@
         "enableLog": false,
         "logLevel": "error",
         "positionVsParent": "atEquipment",
-        "positionIcon": "⊥",
+        "positionIcon": "\u22a5",
         "hasDistance": false,
         "distance": "",
         "controlMode": "levelbased",
@@ -1066,5 +1069,68 @@
         "modules": {
             "EVOLV": "1.0.29"
         }
+    },
+    {
+        "id": "ui_chart_pumping_perccontrol",
+        "type": "ui-chart",
+        "z": "77f00aef1c966167",
+        "g": "grp_status_panel",
+        "group": "ui_group_trends",
+        "name": "percControl",
+        "label": "percControl (%) \u2014 pumping-station demand",
+        "order": 5,
+        "width": 6,
+        "height": 4,
+        "chartType": "line",
+        "category": "topic",
+        "categoryType": "msg",
+        "xAxisLabel": "time",
+        "xAxisType": "time",
+        "xAxisProperty": "",
+        "xAxisPropertyType": "timestamp",
+        "xAxisFormat": "",
+        "xAxisFormatType": "auto",
+        "yAxisLabel": "%",
+        "yAxisProperty": "payload",
+        "yAxisPropertyType": "msg",
+        "xmin": "",
+        "xmax": "",
+        "ymin": "0",
+        "ymax": "100",
+        "removeOlder": "15",
+        "removeOlderUnit": "60",
+        "removeOlderPoints": "",
+        "bins": 10,
+        "action": "append",
+        "stackSeries": false,
+        "pointShape": "circle",
+        "pointRadius": 4,
+        "interpolation": "linear",
+        "showLegend": false,
+        "className": "",
+        "colors": [
+            "#A347E1",
+            "#FF0000",
+            "#FF7F0E",
+            "#2CA02C",
+            "#0095FF",
+            "#D62728",
+            "#FF9896",
+            "#9467BD",
+            "#C5B0D5"
+        ],
+        "textColor": [
+            "#666666"
+        ],
+        "textColorDefault": true,
+        "gridColor": [
+            "#e5e5e5"
+        ],
+        "gridColorDefault": true,
+        "x": 1240,
+        "y": 560,
+        "wires": [
+            []
+        ]
     }
-]
+]

pumpingStation.html

@@ -23,7 +23,7 @@
 <script>//test
   RED.nodes.registerType("pumpingStation", {
     category: "EVOLV",
-    color: "#0c99d9", // color for the node based on the S88 schema
+    color: "#8B4513",
     defaults: {
       name: { value: "" },
 
@@ -86,6 +86,8 @@
       shiftArmPercent: { value: 95 },
       startLevel: { value: 1 },     // m, pump-on threshold (engagement edge)
       stopLevel: { value: 0.5 },    // m, pump-off threshold (hysteresis fall-back)
+      holdLevel: { value: 1 },      // m, ramp 0%-foot; defaults to startLevel (= no hold zone)
+      deadZoneKeepAlivePercent: { value: 1 }, // % emitted across [stopLevel, startLevel] keep-alive band
       minLevel: { value: 0.3 },     // m, hard-stop (just above outflow pipe top)
       maxLevel: { value: 3.8 },     // m, 100% demand saturation
       flowSetpoint: { value: null },
@@ -418,6 +420,11 @@
         <input type="number" id="node-input-stopLevel" min="0" step="0.01" />
         <span class="ps-unit">m</span>
       </div>
+      <div class="ps-row" data-stroke="#27AE60" data-couples-line="ps-mode-line-holdLevel">
+        <div><label>holdLevel</label><div class="ps-sub">0 % ramp foot — leave at startLevel for no hold band</div></div>
+        <input type="number" id="node-input-holdLevel" min="0" step="0.01" />
+        <span class="ps-unit">m</span>
+      </div>
       <div class="ps-row ps-readonly" data-stroke="#1F4E79" data-couples-line="ps-mode-line-inflowLevel">
         <div><label>inflowLevel</label><div class="ps-sub">from basin above</div></div>
         <span id="ps-mode-readout-inflow" class="ps-readonly-val">— m</span>
@@ -475,6 +482,7 @@
       <line id="ps-mode-line-dryRunLevel"  y1="24" y2="140" stroke="#C0392B" stroke-dasharray="2 2" />
       <line id="ps-mode-line-startLevel" y1="24" y2="140" stroke="#1E8449" stroke-dasharray="2 2" />
       <line id="ps-mode-line-stopLevel" y1="24" y2="140" stroke="#7D3C98" stroke-dasharray="2 2" />
+      <line id="ps-mode-line-holdLevel" y1="24" y2="140" stroke="#27AE60" stroke-dasharray="2 2" />
       <line id="ps-mode-line-inflowLevel" y1="24" y2="140" stroke="#1F4E79" stroke-dasharray="2 2" />
       <line id="ps-mode-line-maxLevel" y1="24" y2="140" stroke="#D68910" stroke-dasharray="2 2" />
       <line id="ps-mode-line-overflowLevel" y1="24" y2="140" stroke="#C0392B" stroke-dasharray="2 2" />
@@ -565,6 +573,7 @@
     <label for="node-input-dbaseOutputFormat"><i class="fa fa-database"></i> Database Output</label>
     <select id="node-input-dbaseOutputFormat" style="width:60%;">
       <option value="influxdb">influxdb</option>
+      <option value="frost">frost</option>
       <option value="json">json</option>
       <option value="csv">csv</option>
     </select>

src/basin/thresholdValidator.js

@@ -4,7 +4,14 @@
 //
 // Invariants enforced (level-space, bottom → top):
 //   0 < outflowLevel < inflowLevel < overflowLevel ≤ basinHeight
-//   dryRunLevel ≤ minLevel ≤ startLevel ≤ inflowLevel < maxLevel ≤ highVolumeSafetyLevel < overflowLevel
+//   dryRunLevel ≤ minLevel ≤ startLevel ≤ holdLevel < maxLevel ≤ highVolumeSafetyLevel < overflowLevel
+//
+// startLevel is INTENTIONALLY not constrained against inflowLevel: setting
+// startLevel above the gravity-feed inlet is the "buffer in the sewer"
+// configuration where the upstream pipe network is used as overflow storage
+// before pumping engages. holdLevel (optional, defaults to startLevel when
+// omitted) is the 0 % ramp foot — pumps engage at startLevel but hold at
+// min flow until level rises through holdLevel.
 //
 // dryRunLevel and highVolumeSafetyLevel are DERIVED from safety percentages.
 // The validator recomputes them so a config that places minLevel below the
@@ -56,14 +63,26 @@ function validateThresholdOrdering(basin, levelbased, safety) {
   const points = computeSafetyPoints(basin, safety);
   const { dryRunLevel, highVolumeSafetyLevel } = points;
 
+  // holdLevel is optional — when omitted (null/undefined/NaN) it equals
+  // startLevel at runtime, so skip both holdLevel-related checks in that
+  // case (the canonical engine semantics still hold). Explicit null/undefined
+  // check first so `Number(null) === 0` doesn't accidentally flag a default
+  // schema value as a real operator-provided one.
+  const rawHold = lvl.holdLevel;
+  const holdLevelProvided = rawHold != null && Number.isFinite(Number(rawHold));
+  const holdLevel = holdLevelProvided ? Number(rawHold) : null;
+
   const checks = [
     ['outflowLevel',  basin.outflowLevel,  '<',  'inflowLevel',           basin.inflowLevel],
     ['inflowLevel',   basin.inflowLevel,   '<',  'overflowLevel',         basin.overflowLevel],
     ['overflowLevel', basin.overflowLevel, '<=', 'basinHeight',           basin.heightBasin],
     ['dryRunLevel',   dryRunLevel,         '<=', 'minLevel',              lvl.minLevel],
     ['minLevel',      lvl.minLevel,        '<=', 'startLevel',            lvl.startLevel],
-    ['startLevel',    lvl.startLevel,      '<=', 'inflowLevel',           basin.inflowLevel],
     ['startLevel',    lvl.startLevel,      '<',  'maxLevel',              lvl.maxLevel],
+    ...(holdLevelProvided ? [
+      ['startLevel',  lvl.startLevel,      '<=', 'holdLevel',             holdLevel],
+      ['holdLevel',   holdLevel,           '<',  'maxLevel',              lvl.maxLevel],
+    ] : []),
     ['maxLevel',      lvl.maxLevel,        '<=', 'highVolumeSafetyLevel', highVolumeSafetyLevel],
   ];
 

src/commands/handlers.js

@@ -88,9 +88,14 @@ exports.setOutflow = (source, msg) => {
 
 exports.setDemand = (source, msg, ctx) => {
   const log = _logger(source, ctx);
-  const demand = Number(msg.payload);
+  // generalFunctions/commandRegistry's _normaliseUnits has already converted
+  // msg.payload to m3/h (the descriptor's units.default — see
+  // commands/index.js). Accepts {value, unit} objects upstream; we just read
+  // the normalized number here. _manualDemand is stored in m3/h, no further
+  // conversion needed.
+  const demand = Number(msg?.payload);
   if (!Number.isFinite(demand)) {
-    log?.warn?.(`set.demand: invalid Qd value '${msg.payload}'`);
+    log?.warn?.(`set.demand: invalid Qd value '${JSON.stringify(msg?.payload)}'`);
     return;
   }
   if (source.mode !== 'manual') {

src/control/levelBased.js

@@ -7,7 +7,9 @@
 //      through the dead band [stopLevel, startLevel] emitting a small
 //      keep-alive demand so MGC keeps a single pump draining the basin.
 //   3. Up-curve mapping — level mapped to demand 0..100 % across
-//      [inflowLevel, maxLevel] using linear or log shape.
+//      [max(startLevel, inflowLevel), maxLevel] using linear or log shape.
+//      Foot at startLevel when startLevel > inflowLevel allows buffering
+//      in the upstream sewer above the gravity-feed point.
 //   4. Shifted-ramp hysteresis — when the up-curve crosses
 //      shiftArmPercent the strategy ARMS; on the next filling→draining
 //      flip it captures the up-curve value as `hold`; while draining
@@ -45,13 +47,21 @@ function _scaleLevelToFlowPercent(level, rampFoot, rampTop, levelbased) {
 
 async function _applyMachineGroupLevelControl(machineGroups, percentControl, logger) {
   if (!machineGroups || Object.keys(machineGroups).length === 0) return;
-  await Promise.all(
+  // The caller (run() below) already gated turn-off via the minLevel
-    Object.values(machineGroups).map((group) =>
+  // hard-stop, stopLevel falling-edge, and the rising-edge engagement gate.
-      group.handleInput('parent', percentControl).catch((err) => {
+  // By the time we get here, pumps should be running — `0 %` is the engaged
-        logger?.error?.(`Failed to send level control to group "${group.config?.general?.name}": ${err.message}`);
+  // "min flow" floor (MGC.setDemand interpolates 0 → dt.flow.min), NOT a
-      })
+  // soft turn-off. Forward unconditionally.
-    )
+  const forward = (group) => {
-  );
+    if (typeof group.setDemand !== 'function') {
+      logger?.error?.(`Group "${group.config?.general?.name}" missing setDemand — refusing to call handleInput with a percent value`);
+      return Promise.resolve();
+    }
+    return Promise.resolve(group.setDemand(percentControl, '%')).catch((err) => {
+      logger?.error?.(`Failed to send level control to group "${group.config?.general?.name}": ${err && err.message}`);
+    });
+  };
+  await Promise.all(Object.values(machineGroups).map(forward));
 }
 
 async function _applyMachineLevelControl(machines, percentControl, logger) {
@@ -118,6 +128,8 @@ async function run(ctx, controlState, direction) {
     controlState.percControl = 0;
     if (host) {
       host._stopHystRunning = false;
+      host._shiftArmed = false;
+      host._shiftHoldValue = null;
       host._lastDirection = direction;
     }
     Object.values(machineGroups || {}).forEach((group) => group.turnOffAllMachines());
@@ -131,13 +143,38 @@ async function run(ctx, controlState, direction) {
     }
   }
 
-  // 3. Up-curve mapping. Foot stays at inflowLevel (the basin's
+  // 3. Engagement gate. Pumps stay OFF until level rises through startLevel
-  // gravity-feed point): demand is 0 % in [startLevel, inflowLevel]
+  //    for the first time (rising-edge); once engaged they stay on until
-  // (the hold zone) and scales 0..100 % across [inflowLevel, maxLevel].
+  //    level drops through stopLevel (falling-edge — handled by case 2).
-  const rampFoot = basin?.inflowLevel ?? cfg.inflowLevel ?? startLevel;
+  //    Without an explicit stopLevel the gate collapses to `level >= startLevel`.
+  //    Moved out of the percentControl path so 0 % can mean "engaged at
+  //    min flow" instead of "stopped". Disengagement also clears the
+  //    shifted-ramp hysteresis so it doesn't survive a stop/start cycle.
+  const isEngaged = host ? host._stopHystRunning : (level >= startLevel);
+  if (!isEngaged) {
+    controlState.percControl = 0;
+    if (host) {
+      host._shiftArmed = false;
+      host._shiftHoldValue = null;
+      host._lastDirection = direction;
+    }
+    Object.values(machineGroups || {}).forEach((group) => group.turnOffAllMachines());
+    return;
+  }
+
+  // 4. Up-curve mapping. Foot = holdLevel (defaults to startLevel; operators
+  //    can raise it to introduce a hold band [startLevel, holdLevel] where
+  //    pumps run at min flow before the ramp begins). `inflowLevel` does NOT
+  //    shape the curve — it's basin geometry, not a control setpoint.
+  //    Explicit null/undefined check first so `Number(null) === 0` doesn't
+  //    silently put the ramp foot at the basin floor.
+  const rawHold = cfg.holdLevel;
+  const holdLevel = (rawHold != null && Number.isFinite(Number(rawHold)))
+    ? Number(rawHold) : startLevel;
+  const rampFoot = Math.max(startLevel, holdLevel);
   const upPct = _scaleLevelToFlowPercent(level, rampFoot, maxLevel, cfg);
 
-  // 4. Shifted-ramp arming.
+  // 5. Shifted-ramp arming.
   if (host) {
     if (cfg.enableShiftedRamp) {
       const armPct = Number.isFinite(cfg.shiftArmPercent) ? cfg.shiftArmPercent : 95;
@@ -177,10 +214,14 @@ async function run(ctx, controlState, direction) {
   let percControl;
   if (!inDrainingHold) {
     if (level < rampFoot) {
-      // While engaged via stopLevel hysteresis AND inside the dead band
+      // Engaged (we passed the gate above) but below the ramp foot. Two
-      // [stopLevel, startLevel], emit a small keep-alive so MGC keeps a
+      // sub-cases:
-      // single pump running.
+      //   (a) Inside the configurable hold band [startLevel, holdLevel] —
-      if (stopThresholdActive && host?._stopHystRunning && level < startLevel) {
+      //       emit 0 %, which MGC's setDemand interpolates to flow.min.
+      //   (b) Inside the falling-edge keep-alive band [stopLevel, startLevel]
+      //       — emit deadZoneKeepAlivePercent (default 1 %) so MGC keeps
+      //       at least one pump turning rather than dispatching a clean min.
+      if (stopThresholdActive && level < startLevel) {
         const keepAlive = Number.isFinite(Number(cfg.deadZoneKeepAlivePercent))
           ? Number(cfg.deadZoneKeepAlivePercent) : 1;
         percControl = Math.max(0, keepAlive);
@@ -212,6 +253,26 @@ async function run(ctx, controlState, direction) {
     `Level-based: level=${level} dir=${direction} armed=${shiftArmed} hold=${shiftHold} pct=${percControl}`
   );
 
+  // We are past every off-gate, so the station is engaged and the computed
+  // demand is meant to drive pumps. If no machine group is registered the
+  // demand has nowhere to go and the pumps stay silent — the signature of a
+  // dropped Port 2 parent↔group registration (e.g. after a partial redeploy
+  // that recreated this node). Warn once until a group reappears so the
+  // failure isn't invisible.
+  const groupCount = machineGroups ? Object.keys(machineGroups).length : 0;
+  if (groupCount === 0) {
+    if (host && !host._warnedNoMachineGroup) {
+      logger?.warn?.(
+        `Level-based control engaged (demand ${percControl.toFixed(1)} %) but no machine group is registered — `
+        + `pumps cannot be driven. The parent↔group registration was likely lost on a partial redeploy; `
+        + `redeploy/restart fully to re-run the Port 2 registration handshake.`
+      );
+      host._warnedNoMachineGroup = true;
+    }
+  } else if (host) {
+    host._warnedNoMachineGroup = false;
+  }
+
   await _applyMachineGroupLevelControl(machineGroups, percControl, logger);
 }
 

src/control/manual.js

@@ -4,13 +4,14 @@ async function run() {
 }
 
 async function forwardDemand(ctx, demand) {
-  const { machineGroups, machines, logger } = ctx;
+  const { machineGroups, machines, unitPolicy, logger } = ctx;
   logger?.info?.(`Manual demand forwarded: ${demand}`);
 
   if (machineGroups && Object.keys(machineGroups).length > 0) {
+    const groupDemand = unitPolicy.convert(demand, 'm3/h', 'm3/s', 'manual demand to machineGroups');
     await Promise.all(
       Object.values(machineGroups).map((group) =>
-        group.handleInput('parent', demand).catch((err) => {
+        group.handleInput('parent', groupDemand).catch((err) => {
           logger?.error?.(`Failed to forward demand to group: ${err.message}`);
         })
       )
@@ -27,6 +28,18 @@ async function forwardDemand(ctx, demand) {
       }
     }
   }
+
+  // Neither a group nor a direct machine is registered, so the operator's
+  // demand silently goes nowhere. Surface it — the usual cause is a dropped
+  // Port 2 parent↔child registration after a partial redeploy.
+  const noGroups = !machineGroups || Object.keys(machineGroups).length === 0;
+  const noMachines = !machines || Object.keys(machines).length === 0;
+  if (noGroups && noMachines) {
+    logger?.warn?.(
+      `Manual demand ${demand} not forwarded — no machine group or machine is registered to this pumping station. `
+      + `Check the parent↔child Port 2 registration (redeploy/restart fully to restore it).`
+    );
+  }
 }
 
 module.exports = {

src/editor/basin-diagram.js

@@ -142,6 +142,7 @@
       // ≤-checks below are skipped rather than false-flagged).
       const basinHraw = fNum('basinHeight');
       const start = fNum('startLevel');
+      const hold  = fNum('holdLevel');
       const inlet = fNum('inflowLevel');
       const max   = fNum('maxLevel');
       const ovfl  = fNum('overflowLevel');
@@ -154,8 +155,12 @@
         issues.push('outflowLevel must be > 0');
       if (!ok(dryLvl, start, '<'))
         issues.push(`dryRunLevel (${(dryLvl ?? NaN).toFixed(2)} m, derived) must be < startLevel — lower dryRun% or raise startLevel`);
-      if (!ok(start, inlet, '<='))
+      if (!ok(start, max, '<'))
-        issues.push('startLevel must be ≤ inflowLevel');
+        issues.push('startLevel must be < maxLevel');
+      if (!ok(start, hold, '<='))
+        issues.push('holdLevel must be ≥ startLevel (use startLevel for no hold band)');
+      if (!ok(hold, max, '<'))
+        issues.push('holdLevel must be < maxLevel');
       if (!ok(inlet, max, '<='))
         issues.push('inflowLevel must be ≤ maxLevel');
       if (!ok(max, ovfl, '<='))

src/editor/bounds.js

@@ -3,8 +3,14 @@
 // the current values of related inputs, so the up/down arrows stop at
 // values that respect the basin hierarchy:
 //
-//   0 < outflowLevel < dryRunLevel < startLevel ≤ inflowLevel
+//   0 < outflowLevel < dryRunLevel < startLevel < maxLevel ≤ overflowLevel ≤ basinHeight
-//       ≤ shiftLevel ≤ maxLevel ≤ overflowLevel ≤ basinHeight
+//   0 < outflowLevel < inflowLevel < overflowLevel ≤ basinHeight
+//
+// startLevel is intentionally NOT clamped against inflowLevel: pushing
+// startLevel above the gravity-feed inlet is the "buffer in the sewer"
+// configuration where upstream pipe storage absorbs flow before pumping
+// engages. The level-based ramp foot is max(startLevel, inflowLevel) so
+// either ordering is valid.
 //
 // The user can still type out-of-range values via the keyboard (HTML5
 // min/max only constrain the spinner). The validation ribbons in
@@ -52,10 +58,10 @@
 
       setBounds('startLevel',
         Number.isFinite(dryRun) ? dryRun + EPS : EPS,
-        inlet ?? max ?? overflow ?? basinHeight);
+        max ?? overflow ?? basinHeight);
 
       setBounds('inflowLevel',
-        start ?? EPS,
+        EPS,
         max ?? overflow ?? basinHeight);
 
       setBounds('maxLevel',
@@ -73,6 +79,14 @@
         Number.isFinite(dryRun) ? dryRun + EPS : EPS,
         start ?? inlet ?? max ?? overflow ?? basinHeight);
 
+      // holdLevel — 0 % ramp foot. Defaults to startLevel (no hold band);
+      // when raised above startLevel, pumps engage at startLevel but emit
+      // 0 % across [startLevel, holdLevel] before the ramp begins. Bounds:
+      // startLevel ≤ holdLevel < maxLevel.
+      setBounds('holdLevel',
+        Number.isFinite(start) ? start : EPS,
+        max ?? overflow ?? basinHeight);
+
       // Shift inputs (only relevant when shifted ramp enabled).
       if (shiftEnabled) {
         setBounds('shiftLevel',

src/editor/index.js

@@ -11,10 +11,13 @@
     return Number.isFinite(v) ? v : null;
   };
 
-  // Set a numeric input's value, or blank if not finite.
+  // Set a numeric input's value, or blank if not finite. Accepts numeric
+  // strings (Node-RED's auto-form-binding stores form values as strings).
   ns.setNumberField = (id, val) => {
     const el = document.getElementById(id);
-    if (el) el.value = Number.isFinite(val) ? val : '';
+    if (!el) return;
+    const num = typeof val === 'number' ? val : parseFloat(val);
+    el.value = Number.isFinite(num) ? num : '';
   };
 
   // Add input + change listeners to a list of node-input-* ids.

src/editor/mode-preview.js

@@ -23,13 +23,16 @@
       const svg = document.getElementById('ps-levelbased-mode-diagram');
       if (!svg) return;
       const start = fNum('startLevel');
+      const hold  = fNum('holdLevel');
       const inlet = fNum('inflowLevel');
       const max = fNum('maxLevel');
       // Optional stopLevel — explicit pump-off threshold. Drawn as its
-      // own marker line; does NOT shift the ramp foot. Must be < startLevel
+      // own marker line; does NOT shift the ramp foot. Renders as long as
-      // for the marker to render.
+      // the typed value is a non-negative number — the start-vs-stop
+      // ordering check belongs to the validation ribbon, not the visual
+      // marker (otherwise the line vanishes while the user is mid-edit).
       const stopRaw = fNum('stopLevel');
-      const stop = Number.isFinite(stopRaw) && stopRaw >= 0 && Number.isFinite(start) && stopRaw < start ? stopRaw : null;
+      const stop = Number.isFinite(stopRaw) && stopRaw >= 0 ? stopRaw : null;
       // dryRunLevel is derived from the basin's outflowLevel + dryRun%
       // (no separate input). Below dryRunLevel the runtime hard-stops;
       // we draw it as the leftmost vertical marker so the user sees
@@ -91,18 +94,17 @@
       };
 
       // Up curve. Engagement edge is startLevel (pump-on threshold); the
-      // ramp foot is inflowLevel — matching the runtime in
+      // ramp foot is holdLevel, with a Math.max(startLevel, …) safety
-      // _controlLevelBased, which scales demand over [inflowLevel, maxLevel].
+      // floor — matching the runtime in levelBased.run.
-      // The OFF baseline is drawn for level < startLevel; between startLevel
+      //   - holdLevel == startLevel (default): no hold band, 0..100 % across
-      // and inflowLevel demand sits flat at 0 % (system armed but not yet
+      //     [startLevel, maxLevel].
-      // ramping); from inflowLevel demand ramps to 100 % at maxLevel.
+      //   - holdLevel > startLevel: pumps engaged across [startLevel,
+      //     holdLevel] at 0 % (= MGC flow.min), then 0..100 % across
+      //     [holdLevel, maxLevel].
       const up = document.getElementById('ps-mode-curve-up');
       const down = document.getElementById('ps-mode-curve-down');
       const downLabel = document.getElementById('ps-mode-curve-down-label');
-      // Runtime falls back to startLevel when inflowLevel is missing
+      const upFoot = Number.isFinite(hold) && hold > start ? hold : start;
-      // (basin?.inflowLevel ?? cfg.inflowLevel ?? startLevel); mirror that
-      // in the preview so the curve is still drawn instead of blank.
-      const upFoot = Number.isFinite(inlet) && inlet > start ? inlet : start;
       if (up) up.setAttribute('points', buildPath(start, upFoot, max));
 
       // Shifted-DOWN curve (only when shift enabled): represents the
@@ -167,6 +169,7 @@
         ['dryRunLevel', dryRun],
         ['startLevel', start],
         ['stopLevel', stop],
+        ['holdLevel', hold],
         ['inflowLevel', inlet],
         ['maxLevel', max],
         ['overflowLevel', overflow],

src/editor/oneditprepare.js

@@ -65,6 +65,17 @@
 
     // Numeric field defaults.
     ns.setNumberField('node-input-startLevel',     node.startLevel);
+    ns.setNumberField('node-input-stopLevel',      node.stopLevel);
+    // holdLevel defaults to startLevel when omitted (no hold band). Show
+    // the saved value if there is one; otherwise mirror startLevel so the
+    // user immediately sees the "no hold band" baseline. Coerce to Number
+    // because Node-RED form-bind stores numeric inputs as strings.
+    const holdNum = parseFloat(node.holdLevel);
+    ns.setNumberField('node-input-holdLevel',
+      Number.isFinite(holdNum) ? holdNum : node.startLevel);
+    const deadZoneNum = parseFloat(node.deadZoneKeepAlivePercent);
+    ns.setNumberField('node-input-deadZoneKeepAlivePercent',
+      Number.isFinite(deadZoneNum) ? deadZoneNum : 1);
     ns.setNumberField('node-input-maxLevel',       node.maxLevel);
     ns.setNumberField('node-input-logCurveFactor', node.logCurveFactor);
     ns.setNumberField('node-input-shiftLevel',     node.shiftLevel);
@@ -77,16 +88,22 @@
     const shiftCheckbox = document.getElementById('node-input-enableShiftedRamp');
     if (shiftCheckbox) shiftCheckbox.checked = !!node.enableShiftedRamp;
 
-    // Bind redraws to the inputs each diagram cares about.
+    // Bind redraws to the inputs each diagram cares about. The basin
+    // diagram itself only paints inflow/outflow/overflow lines, but its
+    // validation ribbon also enforces startLevel/holdLevel/maxLevel
+    // ordering — so it has to refire when any of those change too, or
+    // the "Fix before deploy" ribbon goes stale mid-edit.
     ns.bindRedraw(
       ['basinHeight', 'overflowLevel', 'inflowLevel', 'outflowLevel',
+       'startLevel', 'stopLevel', 'holdLevel', 'maxLevel',
        'dryRunThresholdPercent', 'highVolumeSafetyThresholdPercent'],
       ns.basinDiagram.redraw
     );
     ns.bindRedraw(
       // dryRunLevel is derived (outflowLevel + dryRunThresholdPercent),
       // so the mode preview must redraw when either of those change.
-      ['startLevel', 'maxLevel', 'inflowLevel', 'outflowLevel', 'overflowLevel',
+      ['startLevel', 'stopLevel', 'holdLevel', 'maxLevel',
+       'inflowLevel', 'outflowLevel', 'overflowLevel',
        'dryRunThresholdPercent',
        'levelCurveType', 'logCurveFactor', 'enableShiftedRamp', 'shiftLevel',
        'shiftArmPercent'],
@@ -97,7 +114,7 @@
     // so the next redraw + validation sees the correct min/max attrs.
     ns.bindRedraw(
       ['basinHeight', 'basinVolume', 'overflowLevel', 'maxLevel',
-       'inflowLevel', 'startLevel', 'outflowLevel',
+       'inflowLevel', 'startLevel', 'stopLevel', 'holdLevel', 'outflowLevel',
        'dryRunThresholdPercent', 'highVolumeSafetyThresholdPercent',
        'enableShiftedRamp', 'shiftLevel', 'shiftArmPercent'],
       () => ns.bounds?.apply()

src/editor/oneditsave.js

@@ -50,6 +50,15 @@
     node.logCurveFactor = parseNum('node-input-logCurveFactor');
     node.startLevel = parseNum('node-input-startLevel');
     node.maxLevel = parseNum('node-input-maxLevel');
+    // Persist as numbers — Node-RED's auto-form-binding would store these as
+    // strings, and oneditprepare's setNumberField rejects non-Number values,
+    // so the input would blank out on reopen.
+    const stopLevelVal = parseNum('node-input-stopLevel');
+    node.stopLevel = Number.isFinite(stopLevelVal) ? stopLevelVal : null;
+    const holdLevelVal = parseNum('node-input-holdLevel');
+    if (Number.isFinite(holdLevelVal)) node.holdLevel = holdLevelVal;
+    const deadZoneVal = parseNum('node-input-deadZoneKeepAlivePercent');
+    if (Number.isFinite(deadZoneVal)) node.deadZoneKeepAlivePercent = deadZoneVal;
     // minLevel is no longer a user input — it's the derived dryRunLevel
     // (outflowLevel × (1 + dryRunThresholdPercent/100)). The runtime still
     // uses node.minLevel as the unconditional STOP threshold; we set it

src/measurement/flowAggregator.js

@@ -57,6 +57,32 @@ class FlowAggregator {
     this._predictedFlowState = { inflow: 0, outflow: 0, lastTimestamp: timestamp };
   }
 
+  // Pick the best-available variant for one side of the basin balance.
+  // Mirrors selectBestNetFlow's variant precedence (measured first, then
+  // predicted) but resolves each side independently — so a real measured
+  // upstream sensor + a predicted pump outflow both feed the integrator.
+  // Returns the summed flow at the requested positions. The first variant
+  // that has any registered measurement at one of those positions wins,
+  // even if its sum is 0 (a sensor that reads 0 is still data).
+  _pickFlowSum(positions, flowUnit = 'm3/s') {
+    const buckets = this.measurements.measurements?.flow;
+    if (!buckets) return { sum: 0, variant: null };
+    for (const variant of this.flowVariants) {
+      const variantBucket = buckets[variant];
+      if (!variantBucket) continue;
+      const hasAny = positions.some((pos) => {
+        const posBucket = variantBucket[pos];
+        return posBucket && Object.keys(posBucket).length > 0;
+      });
+      if (!hasAny) continue;
+      return {
+        sum: this.measurements.sum('flow', variant, positions, flowUnit) || 0,
+        variant,
+      };
+    }
+    return { sum: 0, variant: null };
+  }
+
   update() {
     const flowUnit = 'm3/s';
     const now = Date.now();
@@ -64,8 +90,13 @@ class FlowAggregator {
     // Synthetic spill flow lives at its OWN position ('overflow') —
     // not as a child of 'out'. That keeps it out of the operational
     // outflow sum here so no self-subtraction is needed.
-    const inflow = this.measurements.sum('flow', 'predicted', this.flowPositions.inflow, flowUnit) || 0;
+    // Inflow + outflow are resolved per-side: a real measured upstream
-    const outflowReal = this.measurements.sum('flow', 'predicted', this.flowPositions.outflow, flowUnit) || 0;
+    // sensor (variant=measured) + a predicted pump-curve outflow
+    // (variant=predicted) is the common realistic mix.
+    const inflowPick  = this._pickFlowSum(this.flowPositions.inflow,  flowUnit);
+    const outflowPick = this._pickFlowSum(this.flowPositions.outflow, flowUnit);
+    const inflow      = inflowPick.sum;
+    const outflowReal = outflowPick.sum;
 
     if (!this._predictedFlowState) this._predictedFlowState = { inflow, outflow: outflowReal, lastTimestamp: now };
 

src/measurement/measurementRouter.js

@@ -34,7 +34,7 @@ class MeasurementRouter {
 
   onLevelMeasurement(position, value, context = {}) {
     this.measurements.type('level').variant('measured').position(position)
-      .value(value).unit(context.unit);
+      .value(value, context.timestamp, context.unit);
 
     const series = this.measurements.type('level').variant('measured').position(position);
     const levelMeters = series.getCurrentValue('m');

src/nodeClass.js

@@ -37,6 +37,7 @@ class nodeClass extends BaseNodeAdapter {
           minLevel: uiConfig.minLevel,
           startLevel: uiConfig.startLevel,
           stopLevel: uiConfig.stopLevel,
+          holdLevel: uiConfig.holdLevel,
           maxLevel: uiConfig.maxLevel,
           // Editor names the field levelCurveType; runtime uses curveType.
           curveType: uiConfig.levelCurveType || uiConfig.curveType,
@@ -44,6 +45,7 @@ class nodeClass extends BaseNodeAdapter {
           enableShiftedRamp: uiConfig.enableShiftedRamp,
           shiftLevel: uiConfig.shiftLevel,
           shiftArmPercent: uiConfig.shiftArmPercent,
+          deadZoneKeepAlivePercent: uiConfig.deadZoneKeepAlivePercent,
         },
       },
       safety: {

src/specificClass.js

@@ -18,15 +18,21 @@ class PumpingStation extends BaseDomain {
   static name = 'pumpingStation';
 
   // Internal math runs in m3/s for flow and m for level so the volume
-  // integrator (flow × dt) is unit-consistent. Strict canonicals make
+  // integrator (flow × dt) is unit-consistent — canonical stays m3/s, the
-  // unit drift in child-fed measurements an explicit error.
+  // platform-wide convention every cross-node consumer (MGC demand math,
+  // physics-sanity) assumes. Strict canonicals make unit drift in child-fed
+  // measurements an explicit error.
+  // Output flow / netFlowRate are emitted in m3/h so telemetry/dashboard
+  // series land on the same axis as the rest of the pump group (verified
+  // slice #47); the m3/s→m3/h presentation conversion happens at the output
+  // boundary only — it never touches the canonical integrator basis.
   // overflowVolume / underflowVolume are listed in output so the
   // MeasurementContainer keeps the integrator's m³ unit on those streams
   // (FlowAggregator writes spill / underflow per tick).
   static unitPolicy = UnitPolicy.declare({
     canonical: { flow: 'm3/s', pressure: 'Pa', power: 'W', temperature: 'K' },
     output:    {
-      flow: 'm3/s', netFlowRate: 'm3/s', level: 'm', volume: 'm3',
+      flow: 'm3/h', netFlowRate: 'm3/h', level: 'm', volume: 'm3',
       overflowVolume: 'm3', underflowVolume: 'm3',
     },
     requireUnitForTypes: [],
@@ -146,6 +152,7 @@ class PumpingStation extends BaseDomain {
       levelVariants: this.levelVariants,
       volVariants: this.volVariants,
       flowThreshold: this.flowThreshold,
+      unitPolicy: this.unitPolicy,
       host: this,
     };
     Object.defineProperty(ctx, 'machines',      { enumerable: true, get: () => host.machines });
@@ -262,7 +269,7 @@ class PumpingStation extends BaseDomain {
     };
     const { arrow = '❔', fill = 'grey' } = STYLES[this.state?.direction] || {};
     const pct = this.measurements.type('volumePercent').variant('predicted').position('atequipment').getCurrentValue() ?? 0;
-    const netFlowM3h = (this.state?.netFlow ?? 0) * 3600;
+    const netFlowM3h = this.unitPolicy.convert(this.state?.netFlow ?? 0, 'm3/s', 'm3/h', 'status badge netFlow');
     const mode = this.mode || '?';
     const manualPart = this.mode === 'manual' && Number.isFinite(this._manualDemand)
       ? `Qd=${this._manualDemand.toFixed(0)} m³/h` : null;
@@ -285,14 +292,32 @@ class PumpingStation extends BaseDomain {
     const measurementType = child.config.asset.type;
     const eventName = `${measurementType}.measured.${position}`;
 
-    child.measurements.emitter.on(eventName, (eventData = {}) => {
+    const handle = (eventData = {}) => {
       this.logger.debug(
         `Measurement update ${eventName} <- ${eventData.childName || child.config.general.name}: ${eventData.value} ${eventData.unit}`
       );
+      if (measurementType === 'level') {
+        this.measurementRouter.route(measurementType, eventData.value, position, eventData);
+        return;
+      }
       this.measurements.type(measurementType).variant('measured').position(position)
         .value(eventData.value, eventData.timestamp, eventData.unit);
       this.measurementRouter.route(measurementType, eventData.value, position, eventData);
-    });
+    };
+
+    child.measurements.emitter.on(eventName, handle);
+
+    // Seed from the child's current value. The emitter only delivers FUTURE
+    // updates, so a parent that registers after the child already emitted
+    // (e.g. a once-only inject that fired during startup before this
+    // subscription existed) would otherwise never see that value. Replaying
+    // the last sample makes a late subscriber pick up the present state.
+    const series = child.measurements
+      .type(measurementType).variant('measured').position(position).get?.();
+    const sample = series?.getLaggedSample?.(0);
+    if (sample && sample.value != null) {
+      handle({ ...sample, childName: child.config.general.name });
+    }
   }
 
   _subscribePredictedFlow(child) {

test/basic/_probe_upstream_emit.test.js

@@ -0,0 +1,85 @@
+// Throwaway probe — exercises the exact path:
+//   measurement child writes flow.measured.upstream → pumpingStation parent
+//   subscribes → getOutput() (≡ what Port 0 emits).
+// Run with: node --test test/basic/_probe_upstream_emit.test.js
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const PumpingStation = require('../../src/specificClass');
+const { MeasurementContainer, configManager } = require('generalFunctions');
+const EventEmitter = require('node:events');
+
+// Minimal PumpingStation config — matches the editor defaults shape.
+function makePsConfig() {
+  const ui = {
+    name: 'PS', basinVolume: 50, basinHeight: 5,
+    inflowLevel: 3, outflowLevel: 0.2, overflowLevel: 4.5,
+    minHeightBasedOn: 'outlet',
+    controlMode: 'levelbased',
+    minLevel: 1, startLevel: 2, maxLevel: 4,
+    levelCurveType: 'linear',
+    processOutputFormat: 'process', dbaseOutputFormat: 'influxdb',
+  };
+  const cm = new configManager();
+  // Use the same buildConfig pipeline the runtime uses.
+  return cm.buildConfig('pumpingStation', ui, 'ps-probe', {
+    basin: {
+      volume: 50, height: 5, inflowLevel: 3, outflowLevel: 0.2, overflowLevel: 4.5,
+    },
+    hydraulics: { minHeightBasedOn: 'outlet' },
+    control: {
+      mode: 'levelbased',
+      allowedModes: new Set(['levelbased']),
+      levelbased: { minLevel: 1, startLevel: 2, maxLevel: 4, curveType: 'linear' },
+    },
+    safety: {},
+  });
+}
+
+// Fake measurement child that looks exactly like the real one to the router:
+//   - softwareType 'measurement'
+//   - config.asset.type = 'flow'
+//   - config.functionality.positionVsParent = 'upstream'
+//   - .measurements is a real MeasurementContainer with a real emitter
+function makeMeasurementChild(id = 'meas-probe') {
+  const measurements = new MeasurementContainer({
+    autoConvert: true,
+    preferredUnits: { flow: 'm3/s' },
+  });
+  // Real container ships an emitter; sanity check.
+  assert.ok(measurements.emitter instanceof EventEmitter || typeof measurements.emitter?.on === 'function');
+  return {
+    id,
+    source: {
+      config: {
+        general: { id, name: id },
+        functionality: { softwareType: 'measurement', positionVsParent: 'upstream' },
+        asset: { type: 'flow' },
+      },
+      measurements,
+    },
+  };
+}
+
+test('PROBE: measurement child writes flow.measured.upstream — parent surfaces it on getOutput()', () => {
+  const ps = new PumpingStation(makePsConfig());
+  const child = makeMeasurementChild();
+
+  // Register the child the same way the runtime does.
+  ps.childRegistrationUtils.registerChild(child.source, 'upstream');
+
+  // Drive a value through the child's MeasurementContainer the way Channel
+  // does — type/variant/position chain then .value().
+  child.source.measurements
+    .type('flow').variant('measured').position('upstream')
+    .value(12, Date.now(), 'm3/h');   // 12 m³/h ≈ 0.00333 m³/s
+
+  const out = ps.getOutput();
+  const upstreamKeys = Object.keys(out).filter((k) => k.startsWith('flow.measured.upstream'));
+  console.log('flow.measured.upstream.* keys in Port 0 payload:', upstreamKeys);
+  for (const k of upstreamKeys) console.log(`  ${k} = ${out[k]}`);
+
+  // The contract: the parent should surface the upstream measurement.
+  assert.ok(upstreamKeys.length > 0, 'parent must surface flow.measured.upstream.* on Port 0');
+});

test/basic/control-levelBased.basic.test.js

@@ -24,9 +24,10 @@ function makeMeasurements(levelMeters) {
 }
 
 function makeGroup(name) {
-  const calls = { handleInput: [], turnOff: 0 };
+  const calls = { setDemand: [], handleInput: [], turnOff: 0 };
   return {
     config: { general: { name } },
+    setDemand: async (value, unit) => { calls.setDemand.push([value, unit]); },
     handleInput: async (...args) => { calls.handleInput.push(args); },
     turnOffAllMachines: () => { calls.turnOff += 1; },
     _calls: calls,
@@ -59,31 +60,38 @@ test('level < minLevel → STOP: turnOffAllMachines on every group, percControl
   assert.equal(state.percControl, 0);
   for (const g of Object.values(ctx.machineGroups)) {
     assert.equal(g._calls.turnOff, 1, 'turnOffAllMachines called once per group');
-    assert.equal(g._calls.handleInput.length, 0, 'no demand sent in stop zone');
+    assert.equal(g._calls.setDemand.length, 0, 'no demand sent in stop zone');
   }
 });
 
-// basin-docs behavior: between minLevel and the active ramp foot, demand
+// Pre-engagement: pumps haven't reached startLevel yet, so the rising-edge
-// is commanded to 0 % (not "unchanged"). MGC still receives the command;
+// hysteresis gate hasn't armed. Explicit turnOff (NOT a setDemand(0)), so
-// only the explicit minLevel hard-stop path skips handleInput.
+// MGC doesn't kick a pump on at flow.min before the gate is ever passed.
-test('minLevel ≤ level < ramp foot → commands 0 % without shutdown', async () => {
+test('minLevel ≤ level < startLevel (not yet armed) → explicit turnOff', async () => {
   const ctx = makeCtx(1.5);
   const state = { percControl: 17 };
   await levelBased.run(ctx, state);
 
-  assert.equal(state.percControl, 0, 'percControl driven to 0 in the hold zone');
+  assert.equal(state.percControl, 0, 'percControl held at 0 before engagement');
   for (const g of Object.values(ctx.machineGroups)) {
-    assert.equal(g._calls.turnOff, 0);
+    assert.equal(g._calls.turnOff, 1, 'engagement gate calls turnOff');
-    assert.equal(g._calls.handleInput.length, 1, 'one demand=0 forward per group');
+    assert.equal(g._calls.setDemand.length, 0, 'no setDemand before engagement');
-    assert.deepEqual(g._calls.handleInput[0], ['parent', 0]);
   }
 });
 
-test('level == startLevel → percControl == 0 (lower edge of ramp)', async () => {
+test('level == startLevel → percControl == 0 dispatched as setDemand (0 % = min flow, NOT off)', async () => {
   const ctx = makeCtx(2);
   const state = { percControl: null };
   await levelBased.run(ctx, state);
   assert.equal(state.percControl, 0);
+  // Critical: at startLevel pumps are engaged at min flow, NOT turned off.
+  // The bug we're fixing: the previous soft-turnOff at pct≤0 stopped pumps
+  // at this boundary even though the hysteresis was armed.
+  for (const g of Object.values(ctx.machineGroups)) {
+    assert.equal(g._calls.turnOff, 0, 'do not turnOff at startLevel');
+    assert.equal(g._calls.setDemand.length, 1, 'forward 0 % to MGC');
+    assert.deepEqual(g._calls.setDemand[0], [0, '%']);
+  }
 });
 
 test('level == maxLevel → percControl == 100 (upper edge of ramp)', async () => {
@@ -101,19 +109,65 @@ test('level above maxLevel → percControl clamped at 100 (interpolation limit_i
   assert.equal(state.percControl, 100);
 });
 
-test('percControl forwarded to every group via handleInput("parent", percControl)', async () => {
+test('percControl forwarded to every group via setDemand(pct, "%")', async () => {
   const ctx = makeCtx(3); // halfway between startLevel=2 and maxLevel=4 → 50%
   const state = { percControl: null };
   await levelBased.run(ctx, state);
 
   assert.equal(state.percControl, 50);
   for (const g of Object.values(ctx.machineGroups)) {
-    assert.equal(g._calls.handleInput.length, 1, 'one forward per group');
+    assert.equal(g._calls.setDemand.length, 1, 'one forward per group');
-    assert.deepEqual(g._calls.handleInput[0], ['parent', 50]);
+    assert.deepEqual(g._calls.setDemand[0], [50, '%']);
+    assert.equal(g._calls.handleInput.length, 0, 'no raw handleInput — % goes through setDemand');
     assert.equal(g._calls.turnOff, 0);
   }
 });
 
+test('inflowLevel does NOT shape the curve — ramp foot = startLevel regardless', async () => {
+  // startLevel=2, inflowLevel=3, maxLevel=4. Level=2.5 sits between
+  // startLevel and inflowLevel. Pre-fix this was a 0 % "hold zone"; now
+  // the ramp is anchored at startLevel so level=2.5 → 25 %.
+  const ctx = makeCtx(2.5, { levelbased: { minLevel: 1, startLevel: 2, maxLevel: 4 } });
+  ctx.basin = { inflowLevel: 3 };
+  const state = { percControl: null };
+  await levelBased.run(ctx, state);
+  assert.ok(Math.abs(state.percControl - 25) < 1e-9,
+    `expected ~25 % (ramp foot at startLevel, NOT inflowLevel); got ${state.percControl}`);
+});
+
+test('holdLevel > startLevel opts into a hold band [startLevel, holdLevel] at 0 %', async () => {
+  // Same geometry but operator raises holdLevel to 3 so the ramp's 0 %
+  // foot moves up. Level=2.5 should now sit in the hold band: pumps are
+  // engaged but emit 0 % (= MGC's flow.min, NOT turn-off).
+  const ctx = makeCtx(2.5, {
+    levelbased: { minLevel: 1, startLevel: 2, holdLevel: 3, maxLevel: 4 },
+  });
+  const state = { percControl: null };
+  await levelBased.run(ctx, state);
+  assert.equal(state.percControl, 0, '0 % in the configurable hold band');
+  for (const g of Object.values(ctx.machineGroups)) {
+    assert.equal(g._calls.turnOff, 0, 'engaged — must not turnOff in hold band');
+    assert.deepEqual(g._calls.setDemand[0], [0, '%']);
+  }
+});
+
+test('falling-edge keep-alive [stopLevel, startLevel] keeps pumps spinning', async () => {
+  // stopLevel = 0.5, startLevel = 2. Once armed (level ≥ startLevel), the
+  // band [0.5, 2) stays engaged at deadZoneKeepAlivePercent (default 1 %).
+  const ctx = makeCtx(1.5, {
+    levelbased: { minLevel: 0.1, startLevel: 2, stopLevel: 0.5, maxLevel: 4 },
+  });
+  // Pre-arm: simulate that level previously crossed startLevel.
+  ctx.host = { _stopHystRunning: true };
+  const state = { percControl: null };
+  await levelBased.run(ctx, state);
+  assert.equal(state.percControl, 1, 'keep-alive emits 1 % in the [stop, start) band');
+  for (const g of Object.values(ctx.machineGroups)) {
+    assert.equal(g._calls.turnOff, 0);
+    assert.deepEqual(g._calls.setDemand[0], [1, '%']);
+  }
+});
+
 test('no valid level → warns and returns without mutating percControl or calling groups', async () => {
   const ctx = makeCtx(NaN);
   let warned = false;
@@ -128,3 +182,51 @@ test('no valid level → warns and returns without mutating percControl or calli
     assert.equal(g._calls.handleInput.length, 0);
   }
 });
+
+// Regression: a station engaged above startLevel but with no machine group
+// registered (e.g. the Port 2 parent↔group registration was dropped by a
+// partial redeploy) computes a real demand that goes nowhere. The strategy
+// must surface this once, not fail silently. See the 2026-05-27 "PS not
+// reacting to level" trace.
+test('engaged with NO machine group registered → warns once (throttled via host)', async () => {
+  const ctx = makeCtx(3, { levelbased: { holdLevel: 2 } }); // level 3 > startLevel 2 → engaged
+  ctx.machineGroups = {};                                   // registration lost
+  ctx.host = {};
+  const warns = [];
+  ctx.logger.warn = (m) => warns.push(m);
+
+  const state = { percControl: 0 };
+  await levelBased.run(ctx, state);
+
+  assert.ok(state.percControl > 0, 'demand is computed even though there is no group');
+  assert.equal(warns.length, 1, 'warns exactly once');
+  assert.match(warns[0], /no machine group is registered/i);
+  assert.equal(ctx.host._warnedNoMachineGroup, true);
+
+  // Subsequent ticks while still group-less stay quiet (no log spam).
+  await levelBased.run(ctx, state);
+  assert.equal(warns.length, 1, 'throttled: no repeat warning on the next tick');
+});
+
+test('warning re-arms after a group reappears then disappears again', async () => {
+  const ctx = makeCtx(3, { levelbased: { holdLevel: 2 } });
+  ctx.host = {};
+  const warns = [];
+  ctx.logger.warn = (m) => warns.push(m);
+  const state = { percControl: 0 };
+
+  ctx.machineGroups = {};
+  await levelBased.run(ctx, state);
+  assert.equal(warns.length, 1);
+
+  // Group registers again → flag clears, no new warning.
+  ctx.machineGroups = { a: makeGroup('A') };
+  await levelBased.run(ctx, state);
+  assert.equal(warns.length, 1);
+  assert.equal(ctx.host._warnedNoMachineGroup, false);
+
+  // Group lost again → warns once more.
+  ctx.machineGroups = {};
+  await levelBased.run(ctx, state);
+  assert.equal(warns.length, 2, 're-armed after recovery');
+});

test/basic/control-manual.basic.test.js

@@ -4,8 +4,15 @@
 const test = require('node:test');
 const assert = require('node:assert/strict');
 
+const { UnitPolicy } = require('generalFunctions');
 const manual = require('../../src/control/manual');
 
+const unitPolicy = UnitPolicy.declare({
+  canonical: { flow: 'm3/s' },
+  output:    { flow: 'm3/s' },
+  requireUnitForTypes: [],
+});
+
 function makeGroup(name) {
   const calls = { handleInput: [] };
   return {
@@ -28,15 +35,15 @@ function makeLogger() {
   return { info: () => {}, debug: () => {}, warn: () => {}, error: () => {} };
 }
 
-test('forwardDemand calls handleInput("parent", demand) on every machine group', async () => {
+test('forwardDemand calls handleInput("parent", canonical m3/s demand) on every machine group', async () => {
   const groups = { a: makeGroup('A'), b: makeGroup('B'), c: makeGroup('C') };
-  const ctx = { machineGroups: groups, machines: {}, logger: makeLogger() };
+  const ctx = { machineGroups: groups, machines: {}, unitPolicy, logger: makeLogger() };
 
-  await manual.forwardDemand(ctx, 50);
+  await manual.forwardDemand(ctx, 360);
 
   for (const g of Object.values(groups)) {
     assert.equal(g._calls.handleInput.length, 1);
-    assert.deepEqual(g._calls.handleInput[0], ['parent', 50]);
+    assert.deepEqual(g._calls.handleInput[0], ['parent', 0.1]);
   }
 });
 
@@ -54,7 +61,7 @@ test('forwardDemand with no machineGroups but direct machines splits demand even
 
 test('run() is a no-op (manual mode is event-driven)', async () => {
   const groups = { a: makeGroup('A') };
-  const ctx = { machineGroups: groups, machines: {}, logger: makeLogger() };
+  const ctx = { machineGroups: groups, machines: {}, unitPolicy, logger: makeLogger() };
   await manual.run(ctx, { percControl: 0 });
   assert.equal(groups.a._calls.handleInput.length, 0);
 });

test/basic/flowAggregator.basic.test.js

@@ -58,6 +58,48 @@ test('FlowAggregator.update integrates inflow-outflow over delta-t', async () =>
   assert.ok(vol > 2.04 && vol < 2.06, `volume after integration was ${vol}`);
 });
 
+test('FlowAggregator.update integrates measured inflow when predicted side is empty', async () => {
+  // Regression: a real upstream sensor writes `flow.measured.upstream.<id>`
+  // (the measurement node hard-codes variant='measured'), but the integrator
+  // used to read variant='predicted' only — so level stayed flat while the
+  // status row reported +N m³/h. The fix mirrors selectBestNetFlow's
+  // variant precedence per side.
+  const { fa, measurements } = makeAggregator();
+  const t0 = Date.now() - 10_000;
+  // Measured inflow at 'upstream' (one of the inflow position aliases),
+  // no outflow side at all.
+  measurements.type('flow').variant('measured').position('upstream').child('sensor-A')
+    .value(0.01, t0, 'm3/s');
+
+  fa._predictedFlowState = { inflow: 0, outflow: 0, lastTimestamp: t0 };
+  fa.update();
+
+  const vol = measurements.type('volume').variant('predicted').position('atequipment')
+    .getCurrentValue('m3');
+  // Expect minVol(2) + 0.01 × ~10 ≈ 2.10 m3.
+  assert.ok(vol > 2.09 && vol < 2.11, `measured inflow did not integrate: vol=${vol}`);
+});
+
+test('FlowAggregator.update mixes measured inflow with predicted outflow', async () => {
+  // Realistic mix: real upstream sensor (measured) + pump-curve outflow
+  // (predicted). The picker resolves each side independently, so the net
+  // balance uses both.
+  const { fa, measurements } = makeAggregator();
+  const t0 = Date.now() - 10_000;
+  measurements.type('flow').variant('measured').position('upstream').child('sensor-A')
+    .value(0.01, t0, 'm3/s');
+  measurements.type('flow').variant('predicted').position('downstream').child('pump-A')
+    .value(0.004, t0, 'm3/s');
+
+  fa._predictedFlowState = { inflow: 0, outflow: 0, lastTimestamp: t0 };
+  fa.update();
+
+  const vol = measurements.type('volume').variant('predicted').position('atequipment')
+    .getCurrentValue('m3');
+  // minVol(2) + (0.01 - 0.004) × ~10 ≈ 2.06 m3.
+  assert.ok(vol > 2.05 && vol < 2.07, `mixed-variant integration produced vol=${vol}`);
+});
+
 test('FlowAggregator.selectBestNetFlow prefers measured over predicted', async () => {
   const { fa, measurements } = makeAggregator();
   measurements.type('flow').variant('measured').position('in').child('m')

test/basic/replay-on-subscribe.basic.test.js

@@ -0,0 +1,81 @@
+// Late-subscriber replay: a measurement child that already holds a value when
+// the pumpingStation registers it (e.g. a once-only inject that fired during
+// startup before the parent subscribed) must still surface on Port 0. The
+// emitter only delivers future updates, so _subscribeMeasurement seeds from the
+// child's current sample.
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const EventEmitter = require('node:events');
+
+const PumpingStation = require('../../src/specificClass');
+const { MeasurementContainer, configManager } = require('generalFunctions');
+
+function makePsConfig() {
+  const cm = new configManager();
+  return cm.buildConfig('pumpingStation', { name: 'PS' }, 'ps-replay', {
+    basin: { volume: 50, height: 5, inflowLevel: 3, outflowLevel: 0.2, overflowLevel: 4.5 },
+    hydraulics: { minHeightBasedOn: 'outlet' },
+    control: {
+      mode: 'levelbased',
+      allowedModes: new Set(['levelbased']),
+      levelbased: { minLevel: 1, startLevel: 2, maxLevel: 4, curveType: 'linear' },
+    },
+    safety: {},
+  });
+}
+
+function makeFlowMeasurementChild(id = 'meas-replay') {
+  const measurements = new MeasurementContainer({ autoConvert: true, preferredUnits: { flow: 'm3/s' } });
+  assert.ok(typeof measurements.emitter?.on === 'function');
+  return {
+    id,
+    source: {
+      config: {
+        general: { id, name: id },
+        functionality: { softwareType: 'measurement', positionVsParent: 'upstream' },
+        asset: { type: 'flow' },
+      },
+      measurements,
+    },
+  };
+}
+
+test('value written BEFORE registration is replayed on subscribe (once-inject timing)', () => {
+  const ps = new PumpingStation(makePsConfig());
+  const child = makeFlowMeasurementChild();
+
+  // Child already holds a value — emitted into the void before the parent existed.
+  child.source.measurements
+    .type('flow').variant('measured').position('upstream')
+    .value(50, Date.now(), 'm3/h');
+
+  // Parent registers AFTER the value is present. Without replay it would only
+  // catch future emits and surface nothing.
+  ps.childRegistrationUtils.registerChild(child.source, 'upstream');
+
+  const out = ps.getOutput();
+  const upstreamKeys = Object.keys(out).filter((k) => k.startsWith('flow.measured.upstream'));
+  assert.ok(upstreamKeys.length > 0, 'parent must surface flow.measured.upstream.* after late subscribe');
+});
+
+test('no stored value → nothing replayed, no crash', () => {
+  const ps = new PumpingStation(makePsConfig());
+  const child = makeFlowMeasurementChild('empty-child');
+  // Register with an empty child container; replay must be a safe no-op.
+  assert.doesNotThrow(() => ps.childRegistrationUtils.registerChild(child.source, 'upstream'));
+  const out = ps.getOutput();
+  const upstreamKeys = Object.keys(out).filter((k) => k.startsWith('flow.measured.upstream'));
+  assert.equal(upstreamKeys.length, 0, 'no upstream key when child has no value');
+});
+
+test('future emits still delivered after subscribe (listener intact)', () => {
+  const ps = new PumpingStation(makePsConfig());
+  const child = makeFlowMeasurementChild('streaming-child');
+  ps.childRegistrationUtils.registerChild(child.source, 'upstream');
+  // Emit AFTER registration — the normal streaming-sensor path.
+  child.source.measurements.type('flow').variant('measured').position('upstream').value(30, Date.now(), 'm3/h');
+  const out = ps.getOutput();
+  const upstreamKeys = Object.keys(out).filter((k) => k.startsWith('flow.measured.upstream'));
+  assert.ok(upstreamKeys.length > 0, 'normal post-subscribe emit still surfaces');
+});

test/basic/specificClass.test.js

@@ -4,13 +4,14 @@
 const test = require('node:test');
 const assert = require('node:assert/strict');
 
+const { MeasurementContainer } = require('generalFunctions');
 const PumpingStation = require('../../src/specificClass');
 
 // machineGroups is a registry-backed getter (declareChildGetter) — direct
 // assignment is no longer possible. Tests inject mock groups through the
 // real registration handshake so the registry remains the source of truth.
 function registerMockGroup(ps, id, behavior = {}) {
-  const calls = { handleInput: [], turnOff: 0 };
+  const calls = { setDemand: [], handleInput: [], turnOff: 0 };
   const mock = {
     config: {
       general: { id, name: id },
@@ -21,6 +22,8 @@ function registerMockGroup(ps, id, behavior = {}) {
       emitter: { on: () => {} },
       setChildId: () => {}, setChildName: () => {}, setParentRef: () => {},
     },
+    setDemand: behavior.setDemand
+      || (async (value, unit) => { calls.setDemand.push([value, unit]); }),
     handleInput: behavior.handleInput
       || (async (...args) => { calls.handleInput.push(args); }),
     turnOffAllMachines: behavior.turnOffAllMachines
@@ -82,6 +85,39 @@ function makeConfig(overrides = {}) {
   return base;
 }
 
+function makeMeasurementChild({ type = 'level', position = 'atequipment', name = 'child-level' } = {}) {
+  return {
+    config: {
+      general: { id: name, name },
+      functionality: { positionVsParent: position },
+      asset: { type },
+    },
+    measurements: new MeasurementContainer({
+      autoConvert: true,
+      preferredUnits: { level: 'm', flow: 'm3/s', pressure: 'Pa' },
+    }),
+  };
+}
+
+test('level child subscription records one sample per event for level-rate fallback', async () => {
+  const ps = new PumpingStation(makeConfig());
+  const child = makeMeasurementChild();
+
+  ps._subscribeMeasurement(child);
+  child.measurements.type('level').variant('measured').position('atequipment')
+    .value(1.0, 1000, 'm');
+  child.measurements.type('level').variant('measured').position('atequipment')
+    .value(1.1, 3000, 'm');
+
+  const series = ps.measurements.type('level').variant('measured').position('atequipment').get();
+  assert.deepEqual(series.values, [1.0, 1.1]);
+
+  const net = ps.flowAggregator.selectBestNetFlow();
+  assert.equal(net.source, 'level:measured');
+  assert.equal(net.direction, 'filling');
+  assert.ok(Math.abs(net.value - 0.5) < 1e-9, `net flow was ${net.value}`);
+});
+
 test('Basin geometry — derived values', async (t) => {
   const ps = new PumpingStation(makeConfig());
 
@@ -163,7 +199,10 @@ test('Threshold guardrails — _validateThresholdOrdering', async (t) => {
     assert.ok(ps.thresholdIssues.some((i) => i.aName === 'startLevel'));
   });
 
-  await t.test('startLevel > inflowLevel flagged for levelbased rising hold zone', () => {
+  await t.test('startLevel > inflowLevel is allowed (sewer-buffer mode), no issue raised', () => {
+    // Inflow gravity point at 3, startLevel pushed to 3.5 → basin is allowed
+    // to fill past the inlet before pumps engage. levelBased shifts the ramp
+    // foot to startLevel; the validator no longer flags the ordering.
     const ps = new PumpingStation(makeConfig({
       control: {
         mode: 'levelbased',
@@ -171,7 +210,8 @@ test('Threshold guardrails — _validateThresholdOrdering', async (t) => {
         levelbased: { minLevel: 1, startLevel: 3.5, maxLevel: 4, curveType: 'linear' },
       },
     }));
-    assert.ok(ps.thresholdIssues.some((i) => i.aName === 'startLevel' && i.bName === 'inflowLevel'));
+    assert.ok(!ps.thresholdIssues.some((i) => i.aName === 'startLevel' && i.bName === 'inflowLevel'),
+      'startLevel vs inflowLevel ordering must not raise an issue');
   });
 
   await t.test('outflowLevel >= inflowLevel flagged', () => {
@@ -261,51 +301,77 @@ test('Levelbased control zones — _controlLevelBased', async (t) => {
     assert.equal(mock._calls.turnOff, 1);
   });
 
-  await t.test('minLevel ≤ level < active ramp start → commands 0% without shutdown', async () => {
+  await t.test('minLevel ≤ level < active ramp start → soft turnOff (pct=0 no longer dispatched)', async () => {
     const ps = new PumpingStation(makeConfig());
     ps.percControl = 42;  // simulated previous demand
     const mock = registerMockGroup(ps, 'mgc1');
     ps.calibratePredictedLevel(1.5);  // between minLevel=1 and startLevel=2
     await ps._controlLevelBased();
     assert.equal(ps.percControl, 0);
-    assert.equal(mock._calls.handleInput[0][1], 0);
+    // pct=0 → turnOff, no setDemand call (avoids MGC interpolating 0 % to dt.flow.min).
+    assert.equal(mock._calls.turnOff, 1);
+    assert.equal(mock._calls.setDemand.length, 0);
   });
 
-  await t.test('filling: level between startLevel and inflowLevel commands 0%', async () => {
+  await t.test('filling: level between startLevel and inflowLevel ramps from startLevel (no implicit hold zone)', async () => {
     const ps = new PumpingStation(makeConfig());
     const mock = registerMockGroup(ps, 'mgc1');
-    ps.calibratePredictedLevel(2.5);  // startLevel=2, inflowLevel=3
+    ps.calibratePredictedLevel(2.5);  // startLevel=2, inflowLevel=3, maxLevel=4
+    await ps._controlLevelBased('filling');
+    // Ramp foot = startLevel (NOT inflowLevel). lerp(2.5, [2, 4], [0, 100]) = 25.
+    assert.ok(Math.abs(ps.percControl - 25) < 1e-9, `expected ~25 %, got ${ps.percControl}`);
+    assert.equal(mock._calls.turnOff, 0, 'engaged — pumps must not be turned off in the ramp');
+    assert.equal(mock._calls.setDemand.length, 1);
+    assert.ok(Math.abs(mock._calls.setDemand[0][0] - 25) < 1e-9);
+  });
+
+  await t.test('filling: level ≥ maxLevel → percControl clamped at 100, routed via setDemand', async () => {
+    const ps = new PumpingStation(makeConfig());
+    const mock = registerMockGroup(ps, 'mgc1');
+    ps.calibratePredictedLevel(3.5);  // 3/4 of the [2,4] ramp → 75 %.
+    await ps._controlLevelBased('filling');
+    assert.ok(Math.abs(ps.percControl - 75) < 1e-9, `expected ~75 %, got ${ps.percControl}`);
+    assert.equal(mock._calls.setDemand.length, 1);
+    assert.equal(mock._calls.setDemand[0][1], '%');
+    assert.ok(Math.abs(mock._calls.setDemand[0][0] - 75) < 1e-9);
+  });
+
+  await t.test('filling: holdLevel raises the ramp foot — explicit hold band [startLevel, holdLevel] sits at 0 %', async () => {
+    const ps = new PumpingStation(makeConfig({
+      control: {
+        mode: 'levelbased',
+        allowedModes: new Set(['levelbased']),
+        levelbased: { minLevel: 1, startLevel: 2, holdLevel: 3, maxLevel: 4, curveType: 'linear', logCurveFactor: 9 },
+      },
+    }));
+    const mock = registerMockGroup(ps, 'mgc1');
+    ps.calibratePredictedLevel(2.5);  // inside [startLevel, holdLevel]
     await ps._controlLevelBased('filling');
     assert.equal(ps.percControl, 0);
-    assert.equal(mock._calls.handleInput[0][1], 0);
+    assert.equal(mock._calls.turnOff, 0, 'engaged — hold band runs at MGC flow.min, not off');
+    assert.deepEqual(mock._calls.setDemand[0], [0, '%']);
   });
 
-  await t.test('filling: level ≥ inflowLevel → percControl linearly scaled to [0,100]', async () => {
+  await t.test('shift disabled (default): foot stays at startLevel — falling levels track the ramp down to startLevel', async () => {
-    const ps = new PumpingStation(makeConfig());
-    const mock = registerMockGroup(ps, 'mgc1');
-    ps.calibratePredictedLevel(3.5);  // midpoint of inflowLevel=3 and maxLevel=4
-    await ps._controlLevelBased('filling');
-    // lerp(3.5, [3,4], [0,100]) = 50
-    assert.ok(Math.abs(ps.percControl - 50) < 1e-9);
-    assert.equal(mock._calls.handleInput.length, 1);
-    assert.ok(Math.abs(mock._calls.handleInput[0][1] - 50) < 1e-9);
-  });
-
-  await t.test('shift disabled (default): foot stays at inflowLevel even after fall', async () => {
     const ps = new PumpingStation(makeConfig());
     registerMockGroup(ps, 'mgc1');
-    // Climb past inflowLevel and beyond, then fall to a level inside [start..inflow].
+    // Climb above startLevel, then fall to a level inside [start, inflow]. With
+    // the new semantics (ramp foot = startLevel, NOT inflowLevel) the falling
+    // level still produces a positive demand on the way down.
     ps.calibratePredictedLevel(3.8);
     await ps._controlLevelBased();
     assert.ok(ps.percControl > 0);
-    ps.calibratePredictedLevel(2.5);  // between startLevel=2 and inflowLevel=3
+    ps.calibratePredictedLevel(2.5);  // startLevel=2, maxLevel=4 → 25 %
     await ps._controlLevelBased();
-    // Without shift the foot is inflowLevel → 0% in the hold zone.
+    assert.ok(Math.abs(ps.percControl - 25) < 1e-9, `expected 25 % on the down ramp, got ${ps.percControl}`);
-    assert.equal(ps.percControl, 0);
   });
 
-  await t.test('shift enabled: arming on % threshold + hold-then-ramp on draining', async () => {
+  await t.test('shift enabled: arming on % threshold + hold-then-ramp on draining (with holdLevel pinning the foot)', async () => {
-    // Geometry: inflow=3, max=4 → up curve goes 0%@3 to 100%@4.
+    // The original shifted-ramp test was authored against the legacy ramp
+    // foot = inflowLevel (=3). With the new defaults the foot moves to
+    // startLevel (=2), which changes every percentage in the trace. Pin
+    // the foot back to 3 by setting holdLevel = 3 — that keeps this test's
+    // arithmetic self-consistent: up curve goes 0 %@3 to 100 %@4.
     //   shiftArmPercent=80 ⇒ arms when up curve ≥ 80 % i.e. level ≥ 3.8.
     //   shiftLevel=3.5 ⇒ held output starts ramping down at this level.
     const ps = new PumpingStation(makeConfig({
@@ -313,7 +379,7 @@ test('Levelbased control zones — _controlLevelBased', async (t) => {
         mode: 'levelbased',
         allowedModes: new Set(['levelbased']),
         levelbased: {
-          minLevel: 1, startLevel: 2, maxLevel: 4, curveType: 'linear', logCurveFactor: 9,
+          minLevel: 1, startLevel: 2, holdLevel: 3, maxLevel: 4, curveType: 'linear', logCurveFactor: 9,
           enableShiftedRamp: true, shiftLevel: 3.5, shiftArmPercent: 80,
         },
       },
@@ -355,7 +421,9 @@ test('Levelbased control zones — _controlLevelBased', async (t) => {
         mode: 'levelbased',
         allowedModes: new Set(['levelbased']),
         levelbased: {
-          minLevel: 1, startLevel: 2, maxLevel: 4, curveType: 'linear', logCurveFactor: 9,
+          // Pin the ramp foot at 3 via holdLevel — keeps legacy arithmetic
+          // self-consistent with the original test (up curve 0 %@3 → 100 %@4).
+          minLevel: 1, startLevel: 2, holdLevel: 3, maxLevel: 4, curveType: 'linear', logCurveFactor: 9,
           enableShiftedRamp: true, shiftLevel: 3.5, shiftArmPercent: 80,
         },
       },
@@ -381,7 +449,9 @@ test('Levelbased control zones — _controlLevelBased', async (t) => {
       control: {
         mode: 'levelbased',
         allowedModes: new Set(['levelbased']),
-        levelbased: { minLevel: 1, startLevel: 2, maxLevel: 4, curveType: 'log', logCurveFactor: 9 },
+        // holdLevel=3 keeps ramp foot at 3 so x=0.5 means level=3.5, matching
+        // the legacy assertion bracket.
+        levelbased: { minLevel: 1, startLevel: 2, holdLevel: 3, maxLevel: 4, curveType: 'log', logCurveFactor: 9 },
       },
     }));
     registerMockGroup(ps, 'mgc1');

test/integration/basic-dashboard-flow.test.js

@@ -4,7 +4,7 @@ const fs = require('node:fs');
 const path = require('node:path');
 
 function loadDashboardFlow() {
-  const flowPath = path.join(__dirname, '../../examples/basic-dashboard.flow.json');
+  const flowPath = path.join(__dirname, '../../examples/02-Dashboard.json');
   return JSON.parse(fs.readFileSync(flowPath, 'utf8'));
 }
 
@@ -22,27 +22,29 @@ function makeContextStub() {
 
 test('basic dashboard flow contains the pumpingStation node and trend widgets', () => {
   const flow = loadDashboardFlow();
-  const ps = flow.find((n) => n.id === 'ps_node_basic');
+  const ps = flow.find((n) => n.type === 'pumpingStation');
-  const parser = flow.find((n) => n.id === 'ps_parse_output');
+  const parser = flow.find((n) => n.id === 'fn_status_split');
-  const levelChart = flow.find((n) => n.id === 'ps_chart_level');
+  const levelChart = flow.find((n) => n.id === 'ui_chart_level');
-  const demandChart = flow.find((n) => n.id === 'ps_chart_demand');
+  const volumeChart = flow.find((n) => n.id === 'ui_chart_volume');
+  const flowChart = flow.find((n) => n.id === 'ui_chart_flow');
 
-  assert.ok(ps, 'ps_node_basic should exist');
+  assert.ok(ps, 'pumpingStation node should exist');
   assert.equal(ps.type, 'pumpingStation');
   assert.equal(ps.controlMode, 'levelbased');
   assert.equal(ps.levelCurveType, 'linear');
-  assert.equal(ps.inletPipeDiameter, 0.4);
+  assert.equal(ps.inletPipeDiameter, 0.3);
   assert.equal(ps.outletPipeDiameter, 0.3);
-  assert.ok(parser, 'ps_parse_output should exist');
+  assert.ok(parser, 'fn_status_split should exist');
-  assert.equal(parser.outputs, 6);
+  assert.equal(parser.outputs, 14);
   assert.equal(levelChart.type, 'ui-chart');
-  assert.equal(demandChart.type, 'ui-chart');
+  assert.equal(volumeChart.type, 'ui-chart');
+  assert.equal(flowChart.type, 'ui-chart');
 });
 
 test('basic dashboard parser routes process fields to charts and state text', () => {
   const flow = loadDashboardFlow();
-  const parser = flow.find((n) => n.id === 'ps_parse_output');
+  const parser = flow.find((n) => n.id === 'fn_status_split');
-  assert.ok(parser, 'ps_parse_output should exist');
+  assert.ok(parser, 'fn_status_split should exist');
 
   const func = new Function('msg', 'context', 'node', parser.func);
   const context = makeContextStub();
@@ -56,8 +58,12 @@ test('basic dashboard parser routes process fields to charts and state text', ()
     payload: {
       'level.predicted.atequipment.default': 3.25,
       'volume.predicted.atequipment.default': 32.5,
+      'volumePercent.predicted.atequipment.default': 65,
+      'flow.predicted.in.default': 0.005,
+      'flow.predicted.out.default': 0.002,
       'netFlowRate.predicted.atequipment.default': 0.003,
       percControl: 25,
+      mode: 'levelbased',
       direction: 'filling',
       safetyState: 'normal',
       isOverflowing: false,
@@ -66,22 +72,25 @@ test('basic dashboard parser routes process fields to charts and state text', ()
   }, context, node);
 
   assert.ok(Array.isArray(out));
-  assert.equal(out.length, 6);
+  assert.equal(out.length, 14);
-  assert.equal(out[0].topic, 'level');
+  assert.equal(out[0].payload, 'levelbased');
-  assert.equal(out[0].payload, 3.25);
+  assert.equal(out[1].payload, 'filling');
-  assert.equal(out[1].topic, 'volume');
+  assert.equal(out[2].payload, '3.25 m');
-  assert.equal(out[1].payload, 32.5);
+  assert.equal(out[3].payload, '32.50 m³');
-  assert.equal(out[2].topic, 'demand');
+  assert.equal(out[4].payload, '65.00 %');
-  assert.equal(out[2].payload, 25);
+  assert.equal(out[5].payload, '25.0 %');
-  assert.equal(out[3].topic, 'net_flow');
+  assert.deepEqual(out[7], { topic: 'Level', payload: 3.25 });
-  assert.equal(out[3].payload, 0.003);
+  assert.deepEqual(out[8], { topic: 'Volume', payload: 32.5 });
-  assert.match(out[4].payload, /normal/);
+  assert.deepEqual(out[9], { topic: 'Volume %', payload: 65 });
-  assert.match(out[5].payload, /level=3.25 m/);
+  assert.deepEqual(out[10], { topic: 'Inflow', payload: 18 });
+  assert.deepEqual(out[11], { topic: 'Outflow', payload: 7.2 });
+  assert.deepEqual(out[12], { topic: 'Net', payload: 10.8 });
+  assert.ok(Array.isArray(out[13].payload));
 });
 
 test('basic dashboard parser keeps previous values when process output sends only changed fields', () => {
   const flow = loadDashboardFlow();
-  const parser = flow.find((n) => n.id === 'ps_parse_output');
+  const parser = flow.find((n) => n.id === 'fn_status_split');
   const func = new Function('msg', 'context', 'node', parser.func);
   const context = makeContextStub();
   const node = { send() {} };
@@ -89,6 +98,6 @@ test('basic dashboard parser keeps previous values when process output sends onl
   func({ payload: { 'level.predicted.atequipment.default': 3.1, percControl: 10 } }, context, node);
   const out = func({ payload: { percControl: 20 } }, context, node);
 
-  assert.equal(out[0].payload, 3.1);
+  assert.equal(out[2].payload, '3.10 m');
-  assert.equal(out[2].payload, 20);
+  assert.equal(out[5].payload, '20.0 %');
 });

test/integration/shifted-ramp-end-to-end.test.js

@@ -37,7 +37,11 @@ function makeConfig() {
       mode: 'levelbased',
       allowedModes: new Set(['levelbased', 'manual']),
       levelbased: {
-        minLevel: 1, startLevel: 2, maxLevel: 4,
+        // holdLevel pins the ramp foot at 3 to preserve the original geometry
+        // (up curve 0 %@3 → 100 %@4). New default would put the foot at
+        // startLevel=2; this test specifically exercises shifted-ramp arming
+        // behaviour, not the ramp-foot semantic itself.
+        minLevel: 1, startLevel: 2, holdLevel: 3, maxLevel: 4,
         curveType: 'linear', logCurveFactor: 9,
         enableShiftedRamp: true, shiftLevel: 3.5, shiftArmPercent: 80,
       },

wiki/Home.md

@@ -61,7 +61,8 @@ What to click in the dashboard after deploy:
 3. `cmd.calibrate.level = 1.5 m` → the volume integrator syncs to a known level.
 4. Watch Port 0 in the debug pane: level rises, predicted volume integrates, demand follows the curve.
 
-![Basic demo — level rises, demand follows](_partial-gifs/pumpingStation/01-basic-demo.gif)
+> [!IMPORTANT]
+> **GIF needed.** Demo recording of the basic flow reacting to mode + inflow clicks. Save as `wiki/_partial-gifs/pumpingStation/01-basic-demo.gif`, target ≤ 1 MB after `gifsicle -O3 --lossy=80`.
 
 ---
 

wiki/Reference-Contracts.md

@@ -19,11 +19,11 @@ The **Unit** column reflects each descriptor's `units: { measure, default }` dec
 |---|---|---|---|---|
 | `set.mode` | `changemode` | `string` | — | Switch the station between auto / manual control modes. |
 | `child.register` | `registerChild` | `string` | — | Register a child node (machine group, measurement, …) with this station. |
-| `cmd.calibrate.volume` | `calibratePredictedVolume` | `any` | `volume` (default `m3`) | Calibrate the predicted-volume integrator to a known basin volume. |
+| `cmd.calibrate.volume` | `calibratePredictedVolume` | any | `volume` (default `m3`) | Calibrate the predicted-volume integrator to a known basin volume. |
-| `cmd.calibrate.level` | `calibratePredictedLevel` | `any` | `length` (default `m`) | Calibrate the predicted-volume integrator to a known basin level. |
+| `cmd.calibrate.level` | `calibratePredictedLevel` | any | `length` (default `m`) | Calibrate the predicted-volume integrator to a known basin level. |
-| `set.inflow` | `q_in` | `any` | `volumeFlowRate` (default `m3/h`) | Push a measured inflow value into the basin balance. |
+| `set.inflow` | `q_in` | any | `volumeFlowRate` (default `m3/h`) | Push a measured inflow value into the basin balance. |
-| `set.outflow` | `q_out` | `any` | `volumeFlowRate` (default `m3/h`) | Push a measured outflow value into the basin balance. |
+| `set.outflow` | `q_out` | any | `volumeFlowRate` (default `m3/h`) | Push a measured outflow value into the basin balance. |
-| `set.demand` | `Qd` | `any` | `volumeFlowRate` (default `m3/h`) | Operator outflow demand setpoint for the station. |
+| `set.demand` | `Qd` | any | `volumeFlowRate` (default `m3/h`) | Operator outflow demand setpoint for the station. |
 
 <!-- END AUTOGEN: topic-contract -->
 

wiki/Reference-Examples.md

@@ -57,7 +57,8 @@ Driver injects are wrapped in four numbered groups: **1. Control mode**, **2. Fl
 3. In manual mode: click `set.demand = 40` — the value surfaces as `manualDemand` on Port 0/1 and in the node status badge.
 4. Click `cmd.calibrate.volume = 25 m³` (or `cmd.calibrate.level = 1.5 m`) to snap the predicted-volume integrator.
 
-![Basic demo — level rises, demand follows](_partial-gifs/pumpingStation/01-basic-demo.gif)
+> [!IMPORTANT]
+> **GIF needed.** Demo recording of steps 1–4. Save as `wiki/_partial-gifs/pumpingStation/01-basic-demo.gif`, target ≤ 1 MB after `gifsicle -O3 --lossy=80`.
 
 ---