Question about RSLogix 5000 ver 19 and 20, and controller compatibily?

I'm trying to add a controller to the I/O configuration of a project in RSLogix 5000.

My main project is a on a 1756-L61 Controller running revision 19

The second project is on a 1756-L71S Controller running revision 20

I was able to add the 1756-L61 controller to the project on the L71S without issue. But when I try to add the L71S to the project on the L61, it does not appear in the list. If I convert the project to revision 20, the L71S is in the list to add to the I/O.

Is there a way to add the L71S to the L61's project without upgrading the firmware on the L61 to 20? Something like an EDS file that I have to install properly?

Thanks

Good question, i'll be seated here and observing.

I assume you are doing this for produced/consumed tags? It has nothing to do with versions. You cannot add a safety processor as a consumer model...Add it as an L61 or L72 (whatever is available as a standard controller in your pick list) and all will be well. I just did this on a recent project and after hours on the phone with AB we resolved it. If you add it as a safety processor, the safety partner will become confused being controlled by two controllers and will lock up. AB was going to generate a tech note on our findings but don't know if it has made the list yet.

I was between versions V17 and V20 FYI, and added my L72S as an L61 in the v17 program and it ran like a champ...no complaints and the produced/consumed tags worked fine.

I just got off of the phone with Tech Support and they said the same thing.

Good to know,
Thanks.