Parsing JT606X Fuel Sensor Data – Computed Attributes vs. Decoder Modification

seed a year ago

Hello everyone,

I'm integrating a JT606X fuel sensor with a Teltonika FMB125. The sensor sends RS232 ASCII data using a custom protocol and responds to the command @01E0006# with a string like @01E130644332180384091068D6#. The fuel level (e.g., 384.09 liters) is encoded as a 6-digit number within a specific substring of this response.

While analog communication between the sensor and FMB125 works seamlessly, digital communication requires parsing the custom protocol. I see two potential approaches:

  1. Modify the TeltonikaProtocolDecoder to handle a new codec (e.g., codec 0x0C) for directly parsing the RS232 data.
  2. Use computed attributes in Traccar, for example, by applying an expression such as CAST(SUBSTRING(text, 16, 6) AS FLOAT) / 100 to extract the fuel level.

Is this computed attribute approach valid for extracting the fuel level?
thanks

Anton Tananaev a year ago

The expression is not valid, but the general approach should work.

seed a year ago

Thanks for your response, Anton.
I understand that the general approach is valid even though my example expression isn’t supported as-is.
Could you please provide some guidance or an example of a valid computed attribute expression for extracting the fuel level from the sensor response? Also, is there any documentation on the functions or syntax available in Traccar’s computed attributes that I could refer to?

Anton Tananaev a year ago