PLC Comms to Modbus device

Hi All,

I have an Ishida checkweigher that is connected to an Ethernet network. I can successfully get information from this machine via OPC.

What I'd like to do is configure a CompactLogix PLC to extract data directly from the device? Is it possible to configure a MSG to achieve this?

Thanks,

From your description we know it can talk Modbus TCP. However, in order for the Logix PLC to talk DIRECTLY using MSG the device has to support Ethernet/IP. Otherwise you will need a gateway that links Ethernet/IP to Modbus TCP.

Your title indicates Modbus but there is nothing in your question as to which version of Modbus (RTU, ASCII, TCP). However, while technically you can message to some versions of Modbus from a CompactLogix (depending on which CompactLogix) it is difficult at best to do it without a third party Gateway device like Spectrum Controls Universal Industrial Gateway (https://www.spectrumcontrols.com/products/webport-solutions/universal-gateway/)
Just to be clear, there are others out there but this is the one I'm familiar with.
Having said that, Rockwell does make a Modbus RTU communications module (I don't remember the model number) for some versions of CompactLogix and they have rather complicated sample code but in either case, it's generally easier to use a Gateway.

Thanks for the info so far.

More info:
The PLC is a 1769-L33ER and the target device is communicating via Modbus TCP/IP as you have both suspected.

@Gazzr:
You said that you have comunication from checkweigher to your OPC server. Is you OPC server communicating with a SCADA ??
If positive you can create a derivated tag inside your SCADA and send data to your PLC and save some money. My SCADA is Ftview SE.

With this method there is no way to send data from PLC to checkweigher, you will need to use a comm module like other people mentioned.

widelto said:

@Gazzr:
You said that you have comunication from checkweigher to your OPC server. Is you OPC server communicating with a SCADA ??
If positive you can create a derivated tag inside your SCADA and send data to your PLC and save some money. My SCADA is Ftview SE.

Click to expand...

I have found a tool within the SCADA that will pass the OPC tag into the PLC. Thanks for the nudge.