GE 90/30 MODBUS CARD

[Guest Guest_Pauly]

Has any one any plc programming examples for using a Horner modbus in a GE 90/30 PLC card as a master to a slave as with address 1. I'm sure that Ive followed the manual example to the letter with no success. Thanks

[Steve Bailey]

I'll repeat the offer I made on another forum. Post the pertinent ladder logic and the details of the Horner module configuration and I'll take a look at it to see if I can spot anything that doesn't look right. Another set of eyes may pick up something you've missed. Quick things to check when comparing your logic to the manual's examples, especially if you're copying the example logic verbatim: Make sure that the %R registers used by the COMREQ aren't being used anywhere else in the program. Make sure you've put the correct value for the rack and slot number in the COMREQ instruction. Make sure you trigger the COMREQ with a one-shot. Try putting coil on the FT output of the COMREQ to see if it's reporting a failure to execute. If it's executing without problems, there should be data returned in the status register that might point you in the right direction. Are you sending anything at all out the module's port? Try monitoring the output with Hyperterm or Procomm or something along those lines to see what you're sending.

[Guest RussB]

Two more things to check. 1. Make sure that your register off-sets are using the correct starting point. Either '0' or '1'. 2. Double check that the data length is correct.