I have just added a ethernet <> RS485 modbus gateway to my system to run my Nilan ventilation system, insted of my USB<>RS485 dongle.
The gateway is a Riot USR-TCP232-410S and its working just fine… However, once every 2-5 minutes I get an timeout read error. The communication still works, but its quite annoying.
This is openhab log:
2020-06-21 23:43:16.468 [ERROR] [wimpi.modbus.io.ModbusTCPTransaction] - execute try 1/1 error: I/O exception: SocketTimeoutException Read timed out. Request: net.wimpi.modbus.msg.ReadMultipleRegistersRequest@60107f (unit id 30 & transaction 58923). Address: /10.4.28.149:502
2020-06-21 23:43:16.472 [ERROR] [wimpi.modbus.io.ModbusTCPTransaction] - execute reached max tries 1, throwing last error: I/O exception: SocketTimeoutException Read timed out. Request: net.wimpi.modbus.msg.ReadMultipleRegistersRequest@60107f (unit id 30 & transaction 58923). Address: /10.4.28.149:502
2020-06-21 23:43:16.477 [WARN ] [rt.modbus.internal.ModbusManagerImpl] - Try 1 out of 3 failed when executing request (ModbusPollerThingHandlerImpl.ModbusPollerReadRequest@b96278[slaveId=30,functionCode=READ_MULTIPLE_REGISTERS,start=300,length=6,maxTries=3]). Will try again soon. Error was I/O error, so reseting the connection. Error details: net.wimpi.modbus.ModbusIOException I/O exception: SocketTimeoutException Read timed out [operation ID f974a621-4cf4-4962-bd7a-6aca4f5eddcc]
This is the setup of the gateway:
I have tried setting UART packet time to 100-200, makes no change.
I have tried activating ModbusTCP poll, makes no difference.
And this is the Bridge setup in openhab:
Bridge modbus:tcp:myNilan [ host="10.4.28.149", port=502, id=30, reconnectAfterMillis=3000 ] {
In another forum @EjvindHald who is using the same gatway mentioned something about terminating the bus with 120ohm resistance. My setup has not this termination… Is it really required?
Its the same cable and same length used with the USB<>RS485 dongle. But I suspect this new gateway could be more sensitive?
Anyone have an idea? @rossko57 perhaps?