XMIT function block


Thread Starter


I am using Concept 2.5 for programming Momentum PLC. Modbus port of 172 JNN 210 32 is used for communicating third party instrument. How to program configure the port as master and do the communication using XMIT function block. The processor is 170 CCC 760 30 (M1 E). Kindly suggest how to do the communication.

Third party instrument supports RS485, Modbus RTU


I don't think that you have the correct processor part number. Do you mean CCC 960 30 or CCC 980 30? Since you have the JNN 210 32 Option Adapter I assume that you have the CCC 960 30. With Concept you will use the XXMIT function and make the RS485 port on the adapter as the Modbus Master. I can email or fax you an example of a similar application. When doing this, be aware that some vendors interpretation of Modbus may give you problems. Do not assume that the parity or stop bits are "default". Also, your 485 wiring will likely require terminations on both ends and watch the polarity of the signals. And, some vendor devices require a read of all information, even though you may just want 1 or 2 words.
If you are using the Modbus Option Adapter 172 JNN 210 32 with a M1E processor, I assume that you are using the 171CCC96030.

You will have to make sure that the third party vendor supports Modbus function code and I suggest that you download the Xxmit PDF from the modicon site. It has some good examples in it.