Modbus using Scratch Pad

Hey Guys,

I am try to use the the Scratch Pad to transfer data to a 3rd party Modbus client. However, the Client did not said modbus ping fail.

On the client side configure the modbus unit ID is 110, confirmed the SNAP PAC R1 IP address is correct, and using port 502.

What else I am missing? Do I need to create a communication handle in the PAC control project?

Thank you!

Hello there,

I think it’s best you familiarize yourself with the Opto22 Modbus/TCP Protocol.
Please download the document here:

I am using the OPTO 22/Modbus TCP protocol with a Direct Logic 06 PLC. My application is very old. They used B1 and B2 OPTO cards with OPTO I/O and the DL06 PLC. They used LabView to tie it all together. I am trying to convert it to PAC Control and PAC Display. I have upgraded the B1 and B2 boards to E1 and E2 boards. I can read the data fine. I am having trouble writing data. Working on that now.