I have a Modbus instrument (VP Flowscope) that I am trying to interface to and I've never worked on Modbus before. I wanted to see if anyone here had some advice for getting this working quickly.
I've written code using the NI DSC toolkit, the code on the NI-Lab (which is pretty much the same as the NI DSC), and another download that can be found here:
http://www.ni.com/example/29756/en/
All of them fail with my setup, although I think I can see a response from the slave device.
Attached are a couple snapshots of my code and a screenshot of what I see on the oscilloscope. On the oscilloscope plot, I believe the second transaction is a response from the slave because if I change any settings (address, parity, etc) then I don't see this transaction.