I have my T3-TB running with sensors and can see the input values with the T3000 software when connected via ethernet.
Now, I want to be able to read the input registers over Modbus rtu on the main 485 port.
I have tried setting up the main rs485 port and reading it with the Modbus tool. However, it appears the Modbus is actually coming via the tcp link. If I disconnect the ethernet, I can’t read the registers.
- Can the ethernet and '485 Modbus port run simultaneously?
- I have set the T3 to be a Modbus slave, ID=255, baud 19200. For testing, register 7484 has a temperature sensor which shows up correctly on the frontend display over ethernet.
- Using the Modbus tool, the Rx light blinks on the T3-TB module, but no data is returned.
When the system is finally deployed, the T3 will be remote in the field , near the sensors. I will have a wired '485 link back to the main plc and it will poll the T3 via Modbus to get the sensor values.
Can you point me to a tutorial or example to help me with this problem?