DSC-BRAIN USER GUIDE · HOW IT WORKS
Sensor trust — offsets, clamps, held and stale
The pipeline a reading goes through before it is shown or acted on, and the horizons that turn a value into HELD, stale or rejected.
● verified for 9.0.0 · firmware train 8.2.0.0
● last verified 2026-09-17 · mirrored 2026-09-15
The pipeline
- Ingest. The brain holds a persistent session to each ESPHome device and records a value when it changes (or once a minute if it does not). Probes poll on a ladder: Normal (60 s) at rest, Fast (5 s) while moisture or EC moves, after a logged watering, feed or flush, or after a probe comes back (READING FAST on Root), and Heartbeat (10 min) when no plant or soil test uses the probe. The hub's climate sensors read every 30 s, and every 3 s while any appliance demand is on. Pin a rung under Settings › Devices › Poll rates; the Fast triggers and holds are under Settings › Sensors › Fast reading.
- Offsets. Per-zone temperature and RH offsets and the probe soft-cal offsets are applied.
- Clamps. A value outside its plausible bounds is rejected (never smoothed) and raises an alert.
- Trust checks. Stuck channels, DHT disagreement between tents, and per-channel peer drift on the probes (median absolute deviation) flag a channel as faulted. Faulted channels are withheld from Need and steering.
- Horizons. Every reading carries its age. Past the stale horizon it is shown HELD on the desks and treated as missing by control logic and rules.
Horizons that matter
| Horizon | Where | Effect |
|---|---|---|
| Hub sensor watchdog (3 min) | Hub firmware | No valid 4×8 temperature: appliance demands off, fans to safe ventilation, Climate sensor fault (critical) |
| Control-side stale (45 s) | Appliance driver | Sonoff relays forced OFF when the hub reading is older |
| Hub not reporting (3 min) | Alerts | Critical alert; checks stop judging frozen readings |
| Probe dark (15 min) | Alerts | Warn alert; steering withheld for that plant |
| Placed sensor stale window | Settings › Sensors | Zigbee / Tuya placed readings dropped from canopy and deltas |
| Reading stale horizon / offline cooldown | Preferences (browser) | When the desks draw HELD and when a flapping device is called offline |
Two leaf offsets
The leaf-to-air offset for leaf VPD is a brain setting (default 2 °C). Check Settings › Sensors if desk VPD and a hand meter disagree by a fixed amount.
Why the desks show less than you expect
A grey tile is a reading the pipeline refused. That is the design: a rejected or withheld number is safer than a wrong one steering a heater.
DSC-Brain user guide · Sensor trust — offsets, clamps, held and stale · this page is edited on the site; the Notion original was retired after the mirror