Producer Consumer: firmware

Been a while since I used P/C but does the firmware revision have to match in all of the involved controllers (allen-bradley)?

In general, Produced/Consumed Tags are independent of controller firmware.

There may be an exception; in v17 an option was added to prefix a DINT to the Consumed Tag that automatically included the Connection status. This probably affects the Consumed Tag only, but I haven't tried to mix controller firmware in combination with that particular feature.

Are you talking about to have a producer/consumer connection? No the PLCs don't have to have the same revision. But the data types involved must match exactly.

What's the difference between "matching" and "matching exactly"?

Emphasis.

In one case I troubleshot, the Producer and Consumer Tags were a UDT with identical members, member datatypes, and sizes. But the UDT Name was different.

In another, we attempted to Produce a UDT that contained 64 bytes, but made the Consuming tag a DINT[8]. No go.

In many ways, those data types were equivalent, but they were not "identical".

I found out about the UDT Name importance a while ago. Seems silly, but the UDT names must be exact too. That's what I meant about matching exactly. Apparently everything must match.

It is amazing how often UDT Produce/Consume tag pairs get created and a subtle error is made making them non-identical. Its one of them things that has you scratching your head for ages until you spot it, then it's blindingly obvious...

The simplest way to prevent this is to Copy both the UDT and the Tag from one project to the other. You will, of course, have to edit the tag properties of one of them.

You can only create Produce/Consume tags offline, so this is no problem.