Mitsubishi Q Series Serial Comms

Has anybody used a Q series Serial Communication card QJ71C24N to talk to a third party device before. I'm trying to get some values (i.e. oil temp, control mode, etc.) from a York compressor via a COMSAB II interface. I've read the manuals which are a little confusing. The message format required is as follows;

'STX-CODE-INDEX-POINT-DATA FIELD-ETX' where,

STX = Starts Telegram
CODE = Indicates Read or Write Telegram
INDEX = Compressor No. To Talk to
POINT = Address of Variable Required
DATA FIELD = Variable Value
ETX = Ens Telegram

Any pointers on how to frame this message for sending and receiving information would be appreciated.

These serial cards can really do it all. The problem is that since they can do so much, they are quite difficult to configure.

You can do it with Gx-Dev but if you can, have the Gx-Configurator add-on software. Its still hard to follow but at least you "see" some results faster.

Are you monitoring what the message is coming out the serial port? you can do that with hyper terminal, with your PC connected to the serial port on the card.

If you think you have everything correct, and you still are not seeing results, you might want to look into "Big Endian / Little Endian".

The following is a link that explains what it is:

http://www.webopedia.com/TERM/b/big_endian.html

I have (and Pierre to I do believe ) had that issue before with mitsubishi.

Good Luck