Modbus TCP Tag Error : Null Value

Hello everyone,
I hope this will find you well!

I’m trying to connect to a Modbus TCP enabled battery to retrieve data from it. I checked first the good connection through the tool “Simply Modbus”. As it can be noticed, the communication has succeed and the data have been well transmitted.

However, when I created OPC server tags using Modbus TCP driver in ignition, I always find null values (note that the device is well connected) :


The OPC item path that I use is for instance:
226 is the UnitID, 259 is the modbus address for the variable “Battery Voltage”.

Could anyone help me please to fix this problem.

Function code 03 is IR not HR so try [Battery]226.IR259

@MatrixEngineering it unfortunately doesn’t work!
Note that in Simply Modbus for example, functions 03 and 04 give the same results.

Delete any other tag related to 226, try HR260, unclick span gaps and see.

Simply Modbus is also using 0-based addressing, so either configure the device in Ignition that way as well or add 1 to the addresses you’re using.

@allnet It works well. Thanks very much!

@Kevin.Herron Yeah absolutely. This was exactly the source of the issue. Thank you Kevin!