Reusing Siemens I/O with Profibus RBC?


Thread Starter

Adam Goldberg

We have a lot of installed Siemens 505 series I/O, controllers, etc. mostly as discrete systems. We will be consolidating control sytems
with something like DeltaV, PlantScape or something equivalent. One of the big issues is reusing perfectly good I/O since we have tons of
it out there.

I just noticed that Siemens makes a Profibus RBC (505-6870) which I guess can be used in place of a regular RBC (505-6851). I know little about Profibus, but would the Profibus RBC allow the rack full of I/O to be addressed as Profibus devices? I know the Profibus RBC won't work on oddball cards like NIM's, etc. - this shouldn't present us a problem.

This would mean that I wouldn't need a PLC - I would do the higher level programming in the new system and control the existing I/O via

Is this correct? If so, is this something you would actually do - is it a pain in the butt, or does it work pretty well?

On a related note, there would be some programs that we would maintain in the Siemens environment for some time to come. The new control system would, I suppose, only be a graphical interface. Any suggestions for a good way to do this would be appreciated. I know it is less than optimal, but I think lots of people do it - I would be interested in hearing your comments.

Thanks for the assistance


What your doing is pretty common. I helped a customer replace a 505 CPU with a Siemens S7-400. He wanted to keep his 505 I/0 because of cost. The 505 I/O just mapped right in.

Whatever system you're looking at - ask them to show you how to import in GSD (GSE) files into their system.