Outside temperature value issue

[RagingBull]

Hi,

I've hooked my Swegon ventilation unit to homelynk with modbus gateway. I can read the fresh air temperature register ok and the values are correct when outside temperature is above 0 °C, but then it goes below the reading jumps to 6552 °C or so. I quess this has something to do how the register is built but I cannot get the readings correct with any bus datatypes. (Should homelynk automatically know how to convert register values to correct negative output value if the datatype is correct?) I think 2byte signed integer should do the trick.

Is there something that I haven't noticed or is this something that has to be dealt with a custom script? Any suggestions.

Here's the line from my JSON file and the Swegons register.

{"name": "Fresh air temperature", "bus_datatype": 8, "type": "inputregister", "address":6200, "value_multiplier":0.1, "units": "°C"},

  SmartModbusRegisterFull1_1.pdf (Size: 312.46 KB / Downloads: 35)

[admin]

Use "datatype": "int16" for signed ModBus values. I suggest using "float16" bus_datatype so decimals can be displayed as well.

[RagingBull]

Thank you very much. This worked like a charm, didn't realize I had to set the datatype separately for the modbus.

[thomasjl]

Is it possible to share your JSON file?

[PacoUmea]

Thank you very much. This worked like a charm, didn't realize I had to set the datatype separately for the modbus.

+1 on thomasjl question.

Would be nice if there were a library with modbus profiler.