Modbus slave

[AhmadHeiba]

Can I uss cFP-2220 as a MODBUS slave (the master will be a PLC) through serial poert (COM1 on the cFP-2220)? I have tried to program it but it doesn't seem to open the port. An example file would be greatly helpful.

Thanks

[RavensFan]

I'm sure you could do this if you write a LabVIEW application to run on the compact Fieldpoint controller to behave as a slave.  The NI Modbus library would go a long ways to get you there.  There is a cRIO library as well.  Obviously that won't run on a cFP directly.  And I haven't looked into it to see what it does.  But it is probably worthwhile looking at that as well for ideas on how to create your own Modbus slave to run on the cFP controller.

[AhmadHeiba]

I though using the library should make it simple. I tried deploying some of the Modbus Library example files on cFP-2220 but that doesn't work, although they work fine if run on a PC. I wonder what it is missing to work on the controller???

[JordanG · Accepted solution]

These articles may be helpful:

How to turn a RT Target into a Modbus Slave using IO Servers

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YFeECAW&l=en-US

Also, you can use both RTU (serial) & TCP (ethernet) to communicate via MODBUS with a fieldpoint controller.

You can view this MODBUS tutorial and see how it applies with the library here:
https://www.ni.com/en/shop/labview/introduction-to-modbus-using-labview.html

You can also communicate via MODBUS by using the MODBUS IO Server, part of the DSC Module (https://www.ni.com/en-us/shop/product/labview-datalogging-and-supervisory-control-module.html). This makes it much easier to implement your application. It also supports MODBUS RTU and ASCII.

Jordan