DF1 Comm to Compactlogix

Hello Everybody. I am trying to read/write to my Compactlogix using DF1 protocol across the serial port to send/get an array of 6 integer values. I have a VB6 program that does this to Micrologix that works just fine. I connect up to the serial (CH0) port on the Compactlogix and I get NAKed from my message. I have mapped an array of 7 integer values to file 7 in the Compactlogix. This is wild new territory for me talking to Compactlogix so any help will be greatly appreciated.

Is there something special I have to do to set the serial port up? or do I have to change the addressing in the DF1 command or something...
the reason for all this is we have a home grown VB6 HMI program that is setting/displaying data on the PLC. This works fine talking to ML1000s but the ML1000 doesnt have the I/Os I need to make it work on the machine I'm retrofitting.

Also, I have read the DF1 protocol manual, as well as the Logix 5000 Data Access, and others... just can't find the "missing piece" I need to get this to work.

Again any inputs will be appreciated...

David

I get NAKed

Click to expand...

I don't wanna be around what that happens!

Heh. Good point, Jay.

Probably it's an error checking difference. MicroLogix controllers use only CRC error checking, while ControlLogix (inexplicably) defaults to the simpler BCC error checking type.

The CompactLogix can be easily configured for CRC error checking in the serial port configuration tab of the Controller Properties dialog in RSLogix 5000.

Ken,

Thanks for the info... I wasn't aware of the difference in the error checking. I appreciate the input and will check on it and let everybody know the results.

I want to thank all of the people who have taken the time to examine this thread, it never seems to be the big stuff that trips me up always the little details... but that's what makes our jobs soooo interesting, huh?

Thanks Again All!