Eurotherm 3216 and GE Fanuc 90-30

I'm trying to get a GE Fanuc 90-30 to communicate with a Eurotherm 3216 Temperature controller via Modbus. I'm not having much luck. I am using a HE693RTM705 Modbus card in the PLC as the Master and the 3216 has a modbus comms built in.

There isn't much to configure on the 3216, so I think my problem is the setup for the PLC. When I initiate the comms the 3216 shows activity on the bus but the setting I am trying to change (the setpoints) stay the same. I get a 1 (one) in the Comm_Req status register showing that the command was initialized OK. However in the Slave Command Block I get an error 93(HEX) - Invalid Modbus Data

Anybody have any suggestions? Anybody ever get a 90-30 talking to one of these things?

The good news is that most of the heavy lifting is done. That code means that the Eurotherm unit received and understood the command from the RTU master. It just rejected the value that you tried to write to it. It could be that you need to swap the high and low bytes of the integer you're trying to send. Why don't you try reading a value from the Eurotherm to see what it looks like in the PLC's %R table. That might give you some hints about how you need to format the data you send to it.

BTW, I'm assuming you meant an error code of 93 hex.

Yeah it was Hex, I read the wrong column.

Thanks for the suggestions, those are good ideas. I wasn't sure what the error meant exactly it is pretty vague in the description. I wasn't sure if the Eurotherm was recieving the message or not or if the PLC didn't like my code. I thought if the PLC didn't like it the Comm Request would have failed but it seems to be working.

The Eurotherm documentation gives a pretty good description of what the Modbus protocol looks like and what it expects the message to look like but the Horner Module description doesn't so when I am setting up the SCB's and MCB's I'm not really sure of what the message is looking like.

I'll get back with my results.

Got it.

The value I was trying to write into the Eurotherm was too low, I had the command and everything set up correctly but the Controller doesn't accept a temperature below 32 degrees. I had the register set at 100 which the controller reads as 10.0 degrees.

Thanks for the reply Steve.