There is a table in the XXMIT:Transmit(Atrium, Compact,Momentum, Quantum)Schneider Manual, Manual #840 USE 00 489 October 2000 on page 62 which states that the data area of the Function Code 02(Read Multiple 1X) in the Master PLC is Ox. The data type of the returning data at the XXMIT connector MsgIn is given as Integer. You cannot connect data type Interger to Ox memory. Apart from some clumsy solutions that I have not yet tried because they seem so improbable, what is the correct way of accepting the returning data from the slave for this function code? Or is the information in the table a misprint?

Clive Libotte
[email protected]

 

The MsgIn parameter is used for when the serial port is simply receiving ASCII data from another source, not when polling for Modbus data from another Modbus device.

For more details on the XXMIT function, there is a document available for download. Go to their website ("public.modicon.com":http://public.modicon.com ) and do a search for XXMIT. It should return a listing for "Concept 2.2 SR2 XXMIT Function Block Description "No Print Copy for Sale" (English)". This document (68 pages) explains in quite a bit of detail how to use the XXMIT, along with examples.

Don Zunti, P.Eng.
Delco Automation Canada

 

Don Zunti,

Thanks for your promt reply. I have the document that you specified, and your first sentence indicated that I had not been paying attention!

To clarify, and avoid confusing others. The returning Modbus data (which will be data type Word, not Integer as I indicated) will be written into the Function 02 data area specified in the Modbus Definition Table. The data area must be of type 0x (register bits). The data is then available for use in the user logic without futher processing. Correct me if I am wrong.

Lesson leant - the Internet is sooo public, do the research before writing!

Kind Regards,
Clive Libotte
[email protected]