Downlink Messages

Configuration commands sent to Thingsee AIR — CO₂ calibration, filter settings, TVOC thresholds, and network roles

Wirepas Ecosystem Reference

This page documents CBOR-encoded commands sent from the cloud to the AIR sensor over the Wirepas mesh network. These messages configure CO₂ measurement behavior, auto-calibration, filters, and reporting thresholds.

Overview

This page documents the Wirepas CBOR commands sent to the sensor over the mesh network. These are the raw on-wire messages — field names and structure differ from the Haltian IoT JSON API exposed to end users.

Downlink messages use the command/response pattern: the cloud sends a command (tsmEv: 30) and the sensor replies with a response (tsmEv: 31) echoing the current configuration with all fields populated.

All messages are CBOR-encoded and sent over Wirepas endpoint 21/21. Each example below shows both the JSON (decoded CBOR) and CBOR (numeric indexes as transmitted on the wire) formats.

For messages the sensor transmits to the cloud, see Uplink Messages. For configuration workflows, see Configuration.

Carbon Dioxide Configuration (tsmId 24200)

The primary configuration message for the CO₂ sensor. Controls measurement accuracy, filtering, auto-calibration, and reporting thresholds.

JSON Property	CBOR Index	Direction	Default	Description
`tsmId`	1	Both	—	Message ID: `24200`
`tsmEv`	2	Both	—	`30` = command, `31` = response
`tsmDstTuid`	7	Command	—	Target device identifier
`transactionId`	25	Both	—	Links command to response
`averaging`	288	Both	`1`	Number of measurements to average (1–10)
`rounding`	289	Both	`1`	Round to nearest N ppm (1–1000)
`samples`	287	Both	`8`	Samples per measurement (1–32)
`staticFilter`	285	Both	`2`	IIR filter strength (0=off, 2–10)
`dynamicFilter`	286	Both	`1`	Reduces static filter lag (0=off, 1+)
`autoCalibration`	269	Both	`192`	Hours between auto-calibration (0–65535)
`calibrationValue`	270	Both	`400`	Target ppm for auto-calibration
`pressureCompensate`	290	Both	`1`	Air pressure compensation (0=off, 1+=on)
`carbonDioxideHysteresis`	281	Both	`10`	Change threshold (ppm) for immediate reporting

Measurement Settings

Field	Range	Default	Effect on Battery
`averaging`	1–10	1	Higher = smoother readings, more power
`rounding`	1–1000	1	Higher = coarser resolution, fewer reports
`samples`	1–32	8	Higher = more accurate, more power

Filter Settings

Field	Range	Default	Description
`staticFilter`	0–10	2	`0`: No filtering. `2–10`: IIR low-pass filter (higher = smoother but more lag)
`dynamicFilter`	0+	1	`0`: Disabled. `1+`: Compensates for static filter lag during rapid changes
`pressureCompensate`	0+	1	`0`: Disabled. `1+`: Adjust readings based on air pressure

Auto-Calibration

Important

Set autoCalibration interval so the sensor is exposed to fresh outdoor air (≈400 ppm) at least once during the period. Poorly configured auto-calibration will cause measurement drift. Default 192 hours (8 days) works well for most office environments.

Field	Default	Description
`autoCalibration`	192	Hours between auto-calibration cycles. Uses lowest detected CO₂ as reference.
`calibrationValue`	400	Target CO₂ concentration (ppm) for auto-calibration. Typically 400 ppm (fresh air).

Command Example

Change CO₂ hysteresis to 5 ppm for more responsive reporting:

{
  "tsmId": 24200,
  "tsmEv": 30,
  "tsmDstTuid": "TSAR01TSC20204001",
  "transactionId": 42,
  "carbonDioxideHysteresis": 5
}

{1: 24200, 2: 30, 7: "TSAR01TSC20204001", 25: 42,
 281: 5}

Response Example

Sensor echoes back all configuration fields with current values:

{
  "tsmId": 24200,
  "tsmEv": 31,
  "tsmTs": 1755064700,
  "tsmTuid": "TSAR01TSC20204001",
  "tsmGw": "TSGW06EWK31903495",
  "transactionId": 42,
  "averaging": 1,
  "rounding": 1,
  "samples": 8,
  "staticFilter": 2,
  "dynamicFilter": 1,
  "autoCalibration": 192,
  "calibrationValue": 400,
  "pressureCompensate": 1,
  "carbonDioxideHysteresis": 5
}

{1: 24200, 2: 31, 3: 1755064700, 4: "TSAR01TSC20204001", 5: "TSGW06EWK31903495",
 25: 42, 288: 1, 289: 1, 287: 8, 285: 2, 286: 1,
 269: 192, 270: 400, 290: 1, 281: 5}

Query Current Configuration

{
  "tsmId": 24200,
  "tsmEv": 30,
  "tsmDstTuid": "TSAR01TSC20204001",
  "transactionId": 43
}

{1: 24200, 2: 30, 7: "TSAR01TSC20204001", 25: 43}

Carbon Dioxide Manual Calibration (tsmId 24201)

Manually calibrate the CO₂ sensor to a known concentration. This is an instantaneous calibration that resets the auto-calibration counter.

JSON Property	CBOR Index	Direction	Description
`tsmId`	1	Both	Message ID: `24201`
`tsmEv`	2	Both	`30` = command, `31` = response
`tsmDstTuid`	7	Command	Target device identifier
`transactionId`	25	Both	Links command to response
`calibrationValue`	270	Both	Current actual CO₂ concentration (ppm)

Tip

For manual calibration, expose the sensor to fresh outdoor air and set calibrationValue to 400 ppm, or use a calibrated reference gas for higher accuracy.

Command Example

Calibrate to 400 ppm (fresh air):

{
  "tsmId": 24201,
  "tsmEv": 30,
  "tsmDstTuid": "TSAR01TSC20204001",
  "transactionId": 44,
  "calibrationValue": 400
}

{1: 24201, 2: 30, 7: "TSAR01TSC20204001", 25: 44,
 270: 400}

Response Example

{
  "tsmId": 24201,
  "tsmEv": 31,
  "tsmTs": 1755064800,
  "tsmTuid": "TSAR01TSC20204001",
  "tsmGw": "TSGW06EWK31903495",
  "transactionId": 44,
  "calibrationValue": 400
}

{1: 24201, 2: 31, 3: 1755064800, 4: "TSAR01TSC20204001", 5: "TSGW06EWK31903495",
 25: 44, 270: 400}

System Interval Configuration (tsmId 1500)

Configure measurement and reporting intervals. Used by all Thingsee sensors.

JSON Property	CBOR Index	Direction	Description
`tsmId`	1	Both	Message ID: `1500`
`tsmEv`	2	Both	`30` = command, `31` = response
`tsmDstTuid`	7	Command	Target device identifier
`transactionId`	25	Both	Links command to response
`measurementInterval`	256	Both	Seconds between measurements
`reportInterval`	258	Both	Seconds between reports

Command Example

{
  "tsmId": 1500,
  "tsmEv": 30,
  "tsmDstTuid": "TSAR01TSC20204001",
  "transactionId": 45,
  "measurementInterval": 30,
  "reportInterval": 300
}

{1: 1500, 2: 30, 7: "TSAR01TSC20204001", 25: 45,
 256: 30, 258: 300}

Response Example

{
  "tsmId": 1500,
  "tsmEv": 31,
  "tsmTs": 1755064900,
  "tsmTuid": "TSAR01TSC20204001",
  "tsmGw": "TSGW06EWK31903495",
  "transactionId": 45,
  "measurementInterval": 30,
  "reportInterval": 300
}

{1: 1500, 2: 31, 3: 1755064900, 4: "TSAR01TSC20204001", 5: "TSGW06EWK31903495",
 25: 45, 256: 30, 258: 300}

Wirepas Node Role (tsmId 1501)

Configures the device’s role in the Wirepas mesh network.

JSON Property	CBOR Index	Direction	Description
`tsmId`	1	Both	Message ID: `1501`
`tsmEv`	2	Both	`30` = command, `31` = response
`tsmDstTuid`	7	Command	Target device identifier
`transactionId`	25	Both	Links command to response
`autoRole`	543	Both	Automatic role selection: `0` = fixed, `1` = auto
`lowLatency`	544	Both	Low-latency mode: `0` = normal, `1` = low latency

Node Role Options

autoRole	lowLatency	Behavior
`1`	`0`	Default — network assigns optimal role
`0`	`0`	Fixed role, standard latency
`0`	`1`	Fixed role, low latency (higher battery usage)
`1`	`1`	Auto role with low latency preference

Command Example

{
  "tsmId": 1501,
  "tsmEv": 30,
  "tsmDstTuid": "TSAR01TSC20204001",
  "transactionId": 46,
  "autoRole": 1,
  "lowLatency": 0
}

{1: 1501, 2: 30, 7: "TSAR01TSC20204001", 25: 46,
 543: 1, 544: 0}

Response Example

{
  "tsmId": 1501,
  "tsmEv": 31,
  "tsmTs": 1755065000,
  "tsmTuid": "TSAR01TSC20204001",
  "tsmGw": "TSGW06EWK31903495",
  "transactionId": 46,
  "autoRole": 1,
  "lowLatency": 0
}

{1: 1501, 2: 31, 3: 1755065000, 4: "TSAR01TSC20204001", 5: "TSGW06EWK31903495",
 25: 46, 543: 1, 544: 0}

Command/Response Pattern

All downlink messages follow the same pattern:

Send command — Set tsmEv: 30, include tsmDstTuid (target device) and transactionId (any integer)
Receive response — Sensor replies with tsmEv: 31, same transactionId, echoing all configuration fields with current values
Verify — Compare response values against command to confirm settings were applied
Query only — Send with only header fields (no config parameters) to read current configuration

Transaction ID

Use transactionId to correlate commands with responses, especially when configuring multiple devices simultaneously. Any integer value works — increment per command for easy tracking.

CBOR Index Reference (Downlink)

CBOR Index	JSON Property	Category
1	`tsmId`	Header
2	`tsmEv`	Header
3	`tsmTs`	Header (response only)
4	`tsmTuid`	Header (response only)
5	`tsmGw`	Header (response only)
7	`tsmDstTuid`	Addressing (command only)
25	`transactionId`	Command tracking
256	`measurementInterval`	System intervals
258	`reportInterval`	System intervals
269	`autoCalibration`	CO₂ auto-calibration interval
270	`calibrationValue`	CO₂ calibration target
281	`carbonDioxideHysteresis`	CO₂ reporting threshold
285	`staticFilter`	IIR filter strength
286	`dynamicFilter`	Dynamic filter compensation
287	`samples`	Samples per measurement
288	`averaging`	Measurement averaging
289	`rounding`	Value rounding
290	`pressureCompensate`	Pressure compensation
543	`autoRole`	Wirepas node role
544	`lowLatency`	Wirepas node role