Adding non-volatile memory to a ControlLogix 5555 controller

I have a ControlLogix 5555 controller (1756-L55). The system has no non-volatile memory. I’d like to try and update the system with non-volatile memory. As far as I can tell I have two options, the first is replacing the existing memory board, and the second is to add a controller that accepts CompactFlash cards.



The 1st option is to replace the existing memory board (1756-M12) with a new memory board (1756-M22) that contains non-volatile memory.



The 2nd option is to replace the controller with a version that accepts CompactFlash cards like the ControlLogix 5561 (1756-L61). I’m not sure this option will even work.

Can I remove the 1756-L55 and replace it with a 1756-L61?

Any thoughts on cost and advantages/dis-advantages would be greatly appreciated.

cherymax said:

Can I remove the 1756-L55 and replace it with a 1756-L61?

Click to expand...

Yes you can. This is the route I would go, or even L62. The L55 is going "Silver Series" this month and only for sale through 2008.

I recommend trading in the 1756-L55 for a 1756-L61/B through the Rockwell "Step Forward" program. Return the old L55 for a 60% discount on the -L61/B.

The 1756-L61/B uses removable CompactFlash memory as the nonvolatile memory, has superior battery life, more robust RAM, faster processing, and support for future firmware releases past v17.

Move fast on the Step Forward program; the eligibility and discount rates usually change at the end of the year.

A few more questions

What's the A/B designate with these controllers?

Why the 62 or the 61 other than more memory?

I was wondering about that step-fwd program yesterday... I didn't think the discounts were so large. That's great!!!

I know it's an old thread, but it's valid now

I am in an identical situation. I have a new L61 controller and was going to put it in the system to replace the L55, but when I changed the controller properties from L55 to L61 in Logix5000, it gave me a warning about invalidating and deleting properties....

One of my co-workers mentioned that timers are handled differently between these two controllers. I am looking into this myself, but thought I would ask here while I'm looking.

Is this controller change a "chop-and-swap"...just download the program into the new controller and plug it in? I haven't been able to find a clear answer in the manuals yet.

I've attached a screenshot of the warning....

Your co-worker might have been thinking about the difference in timers between PLC/SLC/MicroLogix and ControlLogix. PLC/SLC/MicroLogix have a selectable timebase (1 sec, .01 sec) but the ControlLogix controllers all use 0.001 second timebase, so your presets and accumulated values are always in milliseconds.

The warning that RSLogix 5000 gives is only about the Controller Properties; once you change the program to a 1756-L61, you can't load the same program back into a 1756-L55. Fortunately, RSLogix 5000 automatically saves a backup copy of the *.ACD file with a ".v13" or ".v15", or ".v16" that corresponds to the original version of the project.

I don't see any downside to converting a 1756-L55 to a 1756-L61 other than the fact that the nonvolatile memory could possibly be removed (I've actually had some stolen !).

Thanks Ken, I feel a lot better about making the switch now...just have to wait for downtime.

non volatile memory

Hello evrybody
I'm new on this forum and I have a very basic level on plc's
We have mostly OMRON and Siemens plc's in our factory; please can you tell me what kind of memory these plcs have? (I notice that they are equiped with battery)
If there's some trouble with memory, how can I know?
Excuse my broken English.
Best regards

Operators Manual

We would at least need to know the model numbers of the PLCs you are asking about. The best way to find out what you have is to download the manuals for the PLCs from the manufacturer's website.