Hello Teltonika Support,
I am using an FMC125 device and I need to read Modbus (RTU) data from a slave device over the RS485 interface. I would like your guidance on the correct approach.
Device details:
- Model: FMC125
- Firmware version: 04.00.00 Rev:13
- Configurator version: 12.0.0.0
My situation:
- On the RS232\RS485 tab, the available RS485 modes are only: Log Mode, NMEA, LLS, TCP/UDP ASCII, and TCP/UDP Binary. There is no “Modbus” mode.
- In the I/O menu there is no Modbus / RS485 register-mapping section.
- When I use TCP/UDP ASCII mode and forward data to my server (port 8012), I receive corrupted/garbage bytes (repeating “efbfbd” pattern) instead of clean Modbus register values.
My questions:
- Does the FMC125 support native Modbus master functionality over RS485 (polling holding/input registers, function codes, register mapping, data type decoding)?
- If yes, is there a specific firmware version required, and how/where is Modbus configured (parameter IDs, Configurator section, or SMS/GPRS setparam commands)? Please share the documentation or a configuration template.
- If the FMC125 does not support native Modbus, is the recommended approach to use TCP/UDP Binary transparent mode and implement the Modbus master logic (request frames + CRC + response parsing) on my own server side? Please confirm.
- Are there recommended RS485 serial settings (baudrate, parity, stop bits) I should match to my slave device?
My goal is to reliably retrieve decoded Modbus register values from my slave device through the FMC125. Please advise on the best supported method for my hardware and firmware.
Below I attached the server packets I received in my server side…please consider this
Thank you for your help.
Best regards,
SUBHASHINI G
APM KINGSTRACK TECHNOLOGIES
9360846607