PhilipW said:
The method is documented somewhere in the AB technotes, or failing that email me and I will see what I can dig up.
CJH, Philip's solution has potential, if you can spare an extra CPU. The ability to share IO cards in CLX is pretty neat!
The hard part is configuring the messaging between processors. You've got to read the help file, tech notes, and examples to really get the full picture. Here are a few tips:
1. You need to create and configure a MESSAGE tag.
2. Right click the tag in the tag browser to "Go to Message Properties."
3. You're probably going to use a CIP data table Read/Write. It's pretty straight-forward to set up, EXCEPT for the Path.
4. You may be able to use the path browser to find your secondary processor, try that first. If that fails, you need to know that each "step" of the communication link must be defined. For example, you can't just enter IP address of a remote PLC as a path. Here's a sample of a valid ethernet path:
Path: {Enet card name}, 2, {IPAddress}, 1, {Remote CPU Slot #}
The #2 tells the message instruction to communicate out the RJ45 port.
The #1 tells the message to tunnel into the backplane.
The rule that 1 means "backplane" and 2 means "port" is a little hard to find in the help file, so burn it into your memory.
So, for CPUs in the same rack the path should probably be: 1, {Secondary CPU Slot #}.
AK