ControlLogix L73 (RSLogix5000): Redundancy Documentation

Where can I find information on how to implement redundant Allen Bradley Controllers. We have this critical app here that ran as a single PLC for years and was upgraded to a dual PLC redundant pair, but the redundancy was recently proven to not work.

First hit on Google: http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1756-um535_-en-p.pdf

That's why I'm the 'Janitor, I guess.

Thanks!

Will redundancy systems save all Integer and other types of data exactly as is in case of a system crash by any chance? Our systems rely heavily on things like production count, runtime, etc. If a crash would occur in the middle of production would these types of data be lost in the process of switching PLCs?

PS this is with a SLC 5/05, will we also be required to purchase the 1747-BSN Module for this to work?

PlastekGroup said:

Will redundancy systems save all Integer and other types of data exactly as is in case of a system crash by any chance? Our systems rely heavily on things like production count, runtime, etc. If a crash would occur in the middle of production would these types of data be lost in the process of switching PLCs?

PS this is with a SLC 5/05, will we also be required to purchase the 1747-BSN Module for this to work?

Click to expand...

Disregard this post, there's more to it than that.

PlastekGroup:

I've only read a small part of that document, but even without reading *any* of it, redundant (to me) means "no loss". So your PLC will keep chugging along (with just a brief blip during the changeover), but what about the rest of your data path? You'll be trying to get this data out to a Historian or data logger of some kind. Is that machine redundant? Is the path to it redundant?

If the *whole* path isn't redundant, then (to me) you don't have full redundancy, and you're still at risk for loss of data.

So I would say "redundancy" needs to be qualified as either "non-existent", "partial", or "full". And I would bet most implementations are only "partial".