I am reading values from PLC (modbus/tcp) which has analog sensor using modbus node red, and I used input anolog register and read one register. it returns values such as [ 9088]. and it works switch on/off LED when the temperature goes up . I read this value through node-red modbus but I cannot write on LED. I sent zero or one to the coil but it doesn't work and I can't read the values using node-red from coil. I am using the same address for slave (100), and I am not sure if it has different address. could you help me to figure out the problem?
That depends on how the PLC has formatted the data. You will need to look at the specification for your device to see what the value means. Once that is known it should be possible to convert it to a meaningful value.
Thank you, the problem I cant find anything about this PLC, as it is free software and I installed it in raspberry pi.
I have another question, is there any PLC simulator based on Ethernet/IP and I can run it in node-red?