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DS18B20 Temperature Sensors

Antares 4G supports 1-Wire digital temperature sensors based on the DS18B20 chip.

DS18B20 sensors can operate in normal power mode or parasite mode.

⚠️ Purchase note: many low-cost probes are labeled as DS18B20 but do not include a genuine compatible chip. Prefer sensors explicitly indicating parasite-mode support. Example known-working model: https://www.amazon.com/gp/product/B00CHEZ250

Up to 10 temperature sensors can be connected simultaneously, mapped to signals TO0–TO9.

Signals​

SignalDescription
TO0–TO9Temperature threshold signals (one per sensor slot)

Typical Setup Flow​

  1. Connect one or more DS18B20 sensors to the 1-Wire bus.
  2. Query discovered sensors with QXATI.
  3. Assign each physical sensor ID to a logical tag (A–J) with SXATL.
  4. Configure threshold slots (0–9) with SXATO.
  5. Optionally include temperature values in reports using extended tag EA.

Temperature Thresholds​

Each threshold slot (0–9) is associated with one tagged sensor and one threshold value.

Behavior:

  • Positive threshold: use sign 1 (or +) in command encoding.
  • Negative threshold: use sign 0 (or -) in command encoding.
  • Value is fixed-point with one decimal, encoded as 4 digits.
    • Example: 0255 = +25.5°C
    • Example: 0050 with negative sign = -5.0°C
  • A threshold slot cannot be shared by two different sensor tags at the same time.

Commands​

Sensor Information — XATI​

Query all detected sensors:

>QXATI<

Response format:

>RXATI<ID>,<TAG>,<VALUE>;<ID>,<TAG>,<VALUE>...<

Where:

  • TAG is A–J when assigned, or U when unassigned.
  • VALUE is signed fixed-point (+0255 = 25.5°C) or U if no valid reading yet.

Example — two sensors detected, one assigned to tag A reading 21.5°C, one unassigned with no reading yet:

>QXATI<
>RXATI28AABBCCDDEEFF,A,+0215;28112233445566,U,U<

Tag Assignment — XATL​

Assign a sensor ID to a tag (A–J):

>SXATL<TAG><SENSOR_ID><

Example:

>SXATLA28AABBCCDDEEFF<

Query tag assignment:

>QXATL<TAG><

Remove tag assignment:

>SXATL<TAG>U<

Threshold Configuration — XATO​

Set threshold at slot 0–9:

>SXATO<SLOT>1<TAG><SIGN><VALUE4><

Examples:

>SXATO01A10255<   <- Slot 0, Tag A, +25.5°C
>SXATO11A00050<   <- Slot 1, Tag A, -5.0°C

Query threshold by slot:

>QXATO<SLOT><

Remove threshold by slot:

>SXATO<SLOT>U<

Extended Tag: EA​

Add the EA tag to include temperature sensor readings in reports:

>SXAEFA;EA<

Report example:

>REV001234567890+2578250-0802813901234512;EA=A21.50B22.10;ID=IMEI<

Special conditions for EA:

  • Output is tag-prefixed (A..J), not comma-only values.
  • If a sensor has no valid reading yet, it appears as <tag>*.
  • If no sensor has valid readings, the field is EA=A*.

Installation and commissioning tips​

  • Connect and identify sensors one at a time during installation to avoid ID confusion.
  • Record each sensor physical location with its assigned tag (A–J).
  • Validate live values with QXATI before creating threshold events.