How to Connect Labview to a Modicon Quantum PLC (140 CPU 311 10) with Modbus

[Greener28]

I was wondering if anybody could give some advice on how to connect Labview to a Modicon Quantum PLC ( the card is 140 CPU 311 10).  I am wanting to use Labview as an HMI to control the PLC which is being used to implement PID control with a VFD.  Currently I can communicate through Modbus to the PLC for programming using UnityPro XL, but I have no idea how to connect Labview.  I have read the section on NI site "connecting Labview to any PLC through Modbus" but i am still not sure.  Any help will be greatly appreciated. 

[RyanPoPo · Accepted solution]

Hey Greener,

Communicating with PLCs over Modbus usually requires the Datalogging and Supervisory Control (DSC) Module to have that functionality available in LabVIEW. The white paper that you pointed to uses this module, which may explain why you can't get the communication to work. If this is something that you do not have, and purchasing a license isn't an option, then you might be able to use unofficial Modbus libraries to get the functionality you need. I have included a link below to a Modbus library for LabVIEW that you can try.

DSC Module:

http://sine.ni.com/nips/cds/view/p/lang/en/nid/209851

Modbus Library:

http://www.ni.com/example/29756/en/

Regards,

Ryan

[Greener28]

Hi Ryan thanks for the help.  I found out that we did not have datalogging ans Supervisory Control (DSC) Module and it is out of our budget.  However I did receive a few more suggestions as well as yours and I think I have found a solution that will work.  Thanks again for your help.

[RyanPoPo]

You're very welcome!

Regards,

Ryan