I have tag for a Allen-Bradley control logix PLC with firmware v20. I can view all of the tags in ignition, our engineering use the plc like normal and can send other messages to other PLCs on the network. So the PLC seems completely fine and operational. When I create a tag in Igniton from that PLC all I get is BAD value. Any idea's how to fix or troubleshoot BAD values?
Thanks
Do you mean you can browse all the tags in the PLC when creating Ignition tags but not read their values once created?
Yes I can browse all of the tags without issue but can't read them
This is what shows up in my logs
ABControlLogixReadRequest 04Oct2023 11:33:51 Read Request error. Status code: ABResponseStatus{code=15}, First item: Global.Alarm_Buzzer, Transaction: 16920
which makes me wonder If we're missing some setting in the PLC to allow reading
You've either got these tags configured with External Access "None" in the PLC, or you're using the legacy driver with controller running firmware version 20.19+ or 21+.
Yes, I used the Logix Driver and can read now. Thanks, Kevin!
If you really are on a 20.x firmware then you are in a performance dead zone. Using the newer Logix Driver with a pre-21 firmware is worst case scenario.
Ok, the firmware on our PLC is 20.19 and it has been configured with read/write access for each tag. So that should be ok, yes? Also what do you mean by performance dead zone?
With 20.19 you must use the Logix v21 driver. But 20.19 doesn't implement the new instance id based tag access "API" that v21+ firmwares have, so all tag access is done symbolically. It's very slow.
Thanks, that is good to know.