I’m trying to connect an Elite 440 Energy Meter to a TRB145 Gateway (firmware: TRB1_R_00.07.10.2) via RS485 Modbus, with the goal of sending data to ThingsBoard using MQTT.
Issue:
I’m unable to read any values from the energy meter on the gateway. I’ve checked the Modbus client settings but can’t seem to get it working.
Setup:
Connection: RS485
Goal: Data from the energy meter to TRB145 → ThingsBoard (via MQTT).
Data to server: connected through Mqtt to thingsboard
Query:
What Modbus settings or configurations should I check to establish proper communication? Any tips for troubleshooting RS485 issues with this setup?
Latest MODBUS settings:
Modbus TCP server
Modbus Serial Server
Modbus TCP client
Modbus TCP client
Modbus Serial Client
MQTT Modbus Gateway
Modbus TCP over Serial Gateway
Thank you for reaching out. To help troubleshoot the issue, could you first confirm that the RS485 wiring is connected correctly? Specifically:
A (D+) → D_P (pin 4)
B (D-) → D_N (pin 1)
Pin 1 should be shorted with pin 2, and pin 4 shorted with pin 5.
For reference on RS485 pin positioning, please refer to this wiki article.
Additionally, your configuration should be set up using the Modbus Serial Client option. Could you kindly provide a screenshot of your Modbus Serial Client configuration?
Thank you for providing the details and confirming that the wiring is correct.
In your case, if your main goal is to read register data from the Modbus serial server (Elite 440 device), the Modbus TCP Client configuration is unnecessary, as from your current setup, you configured TRP145 as a Modbus TCP server (slave) and are trying to read data from it.
Here you only need to configure the Modbus Serial Client (which, as I can see from your screenshot, is already set up) and additionally, have the serial Modbus device (server/slave) configuration correctly set up under Services → Modbus → Modbus Serial Client.
Please let me know if you need further assistance or have any additional questions.
