Using XMIT instruction for Modicon PLC


Thread Starter

Craig Palmer

Hello, I hope someone can help me. I am using a Modicon Compact 984 E275 PLC and Proworx NXT V2.2 programming software. I want to use the CPU Modbus port to communicate with SEPAM circuit breakers and other devices. I understand that I should use the XMIT instruction to do this but there is no XMIT instruction available in the Proworx software. Is there a loadable for this and if so where is it? I searched the Modicon website and I could not find it. Or should I use a different instruction? (There does not appear to be any other instruction that can be used) Thank you.


Chad Markovich

The XMIT instruction for Modicon Compact PLC's in the 984 Ladder Logic language is available as a loadable that must be purchased. The part number
for the XMIT Single-User license is: 309 COM 455 01. The XMIT function is built into the standard 984LL library for Momentum PLC's, and I believe is
standard for all Modicon PLC's under the Concept IEC libraries as the XXMIT. The XMIT/XXMIT will allow you to use the PLC's Modbus Port as a Master
device to communicate Modbus or ASCII messages. You can purchase the XMIT function block through your local Square D HTAD/HTAD+.
The User Manual for the XMIT loadable is avilable on the Modicon website and can be obtained at the following URL:
The XMIT function allows the PLC to control its serial port as a master and allows for both ASCII and MODBUS communications. I am not familiar with ProWorks so I can only speak from my Modsoft
experience; XMIT is a Loadable with the older Compact Series processors and can be obtained on disk from your Schneider rep. Be sure to load
the NSUP.EXE file into the PLC BEFORE trying to load XMIT.EXE or the block outputs will not function correctly. Once loaded you should be able
to access the function block through ProWorks.
The Read and Write instructions look like they will transmit ASCII through the RS-232 port. They may work for you application.