FMC125 & Modbus with AWS IOT - MQTT format?

[heinburgh]

Hello forum,

When sending a GPRS command in codec 12 to an FMC125 which is connected to a Modbus RTU sensor, we get a valid response with sensor value. The GPRS command which gets this valid result looks like this: 00000000000000100C0105000000080103060600022482010000DA8B

I’m now trying to send this command through AWS IOT but the tracker does not recognise this command format. How do we send the same command to read the Modbus register so the tracker gets it right? The log suggests that something is expected at position 107, so guessing we need to add a bunch more to the command, but cannot find anything online to tell me how to build the command for MQTT.

The tracker logs shows this:

[2024.08.10 19:24:40]-[MQTT] Received MQTT data from socket: 0, {
“CMD”: “00000000000000100C0105000000080103060600022482010000DA8B”
}
[2024.08.10 19:24:40]-[AXL.CLBR] Collecting AXL data
[2024.08.10 19:24:40]-[MQTT] MQTT GPRS command: 00000000000000100C0105000000080103060600022482010000DA8B
[2024.08.10 19:24:40]-[MQTT] ERROR @ m2m_mqtt_commands.c(107):Data ptr is NULL at 107

[heinburgh]

The command is sent through AWS IOT as JSON, and the complete thing looks like this:

{
  "CMD": "00000000000000100C0105000000080103060600022482010000DA8B"
}

I know the setup works because regular command like the one below returns the expected tracker responses.

{
  "CMD": "getinfo"
}

[Maynard]

Hello @heinburgh

Good day, kindly create an HD ticket regarding this topic, it needs POC with the help of our region engineeres.

Please contact your sales manager.

If you don’t have any contacts with our Sale managers, please contact with them on our official website https://teltonika-gps.com/ and click on the “Contact Us” button. When you will click, please fill the form and submit it.

Best Regards
Maynard C