Accessing Parameter values using Labview modbus

[francis@carnotengines.com]

I'm currently having a problem using the Control Techniques Modbus library to access parameter values from the Nidec M700 drive in Labview. 

For context, I'm trying to access the drive health parameter 10.001. This corresponds to a Modbus address of 1000 using the formula from documentation (mm * 100 + ppp - 1). I realise that Modbus addresses start from 40000 but as far as my understanding goes, using the Modbus library blocks removes the need to add this on. I'm using the Nidec Connect app to run the drive whilst running the Labview to extract data.

I have thoroughly checked the IP connection and Ethernet connection/port through command prompt and they seem to be communicating. When it comes to actually accessing the register values, the Modbus 'Read Holding Registers' block fails to return any values when I probe it and in my string output. I have a feeling it's to do with a misinterpretation of the memory addresses/correct block to use. The Labview doesn't flag any errors but doesn't read any register values. I have attached the relevant documentation and my current (basic) Modbus program. Any help would be appreciated!

Thanks!

[pallen]

Modbus can be a little tricky to configure the first time.  

I have had difficulty with some LabVIEW libraries in the past, and success with others.  Try a different Modbus library for LabVIEW if you're able connect with other tools.  

It can often help to use another tool to confirm your Modbus settings and connections are correct. 

https://freemodbus.com/index.html

I'm not familiar with your drive, but you may need to select Modbus RTU or TCP/IP.  Or, there may be other drive-side configurations to set to enable Modbus. 

[LVNinja]

Run the vi Modbus master Example.vi first to learn how to access the addresses and the data format you need to use. 

[francis@carnotengines.com]

I have looked at this block and although I understand it, my issue is dealing with accessing the registers specific to the Nidec M700 addresses and not starting at 0 (like the example block)