Mitsubishi modbus addressing

I am using ignition v7.3.7 to read-write 16 bit integer tag to Mitsubishi PLC.
My application requires an array of 100 to store 100 recipe tags.
At present I have used ‘D’ datatype (for e.g D1000) for modbus addressing. But it so happens that it gives write error while transferring to PLC.

Which datatype should be used to read and write the 16 bit integer value in Mitsubishi PLC?
Also ignition scada value value should exactly match to PLC value for specific tag. That is both ignition and PLC value should be 16 bit.

Please help.Thanks in advance



You don’t say what PLC its (FX,Q,A etc) but generally you can’t talk Modbus to a Mitsubishi PLC directly, you will need an OPC driver (MXOPC from Mitsubishi or Kepware etc)

If you have a Modbus card installed in the PLC then it will need setting up, do you have more info?

Yes mitsubishi driver is present.
Normally if HRI or HRF datatype is used for tag the no write error occurs.
But for INT datatype the error occurs.

Which driver is present?
How are you communicating; exactly

OPC UA Modbus v2 driver

Please specify the steps and datatype for Mitsubishi Modbus addressing of 16 bit Integer.

Exactly which PLC and Modbus card.

PLC is Q06H Modbus card is QJ71MT91

OK, so if you write to something like “HR10” and “HR10” is mapped to say “D10” it generate an error.
what is the error?

you have tested HRF and HRI, do these write with the correct vlaues?

We list all the specific addresses in .txt file and run the application which generates .csv file.
.csv file loads the tags in the tags browser in ignition designer.
My application loads the values in ignition tags and further to the PLC.

If write to ‘D’, its error writing to tag.

HRF, HRI write values to PLC, but overwrite the next 16 bit value resulting to 32 bit value.
Of 32 bits, the first 16 bits occupies data while remaining 16 bits remains zero.

Personally, I’d start with just one or two tags and troubleshoot until those were working OK.

take a look in the gateway logs and perhaps set the console levels to debug for the modbus drivers and perhaps the OPC UA server write service, you might get some useful info there.

Check the configuration of the PLC using a Modbus scanner, I’m fond of Chipkin CAS and its free

If your sure all is OK with the configuration Mitsubishi PLC give IA support a call and let them connect to your development machine, it will be quicker in the long run.