SLC 5/03 Running with no free memory

Hello everyone,

I've just got a quick question here.
On the floor we've got a machine with a SLC 5/03 that currently has 3 instruction words left in memory.
The machine has a few small bugs that could be fixed with programming changes, but that would require a CPU upgrade. The machine is old and will be phased out in the near future.
The operators/supervisors can live with the small bugs, but I'm wondering if there are any issues with running a CPU that full.
I understand that if something came up that required a rewrite (like more automation) we'ld have to upgrade, but other than that is there a problem with leaving the machine as is?

Thanks for your help in advance.

-Shawn

The only issue I know of is that you cannot perform online editing with so little memory left.

Can you post the .rss file? It might be possible to streamline the code and free up some space...

I know about the online edits, that's what drew my attention to how little memory was left.
I can't post the file. sorry guys. I do know that the program isn't as efficient as it could be, it's just justifing the time required to make the changes.

Since you can't post the file take a look at this thread for some ideas:

http://www.plctalk.net/qanda/showthread.php?t=37450

You may want to buy a used CPU from eBay... 5/03's are cheap and if you have a 1747-L531 you would just need a L532, if you have a L532 you would need to go to a 5/04, but still cheap

Do you have any spares CPU's in the plant? it would be a good idea to have a spare for your other PLC's, I used to keep a 1747-L543 as a spare... that way if we had a failure I knew that I had a back up for the SLC's

Only justification I can come up with re-writing.. or upgrading.. is

How much would it cost to not do it? Is it worth the risk of a small memory leak (poor programming) overwriting the last remaining space, or trying an online edit by accident.. or any other possible reason.

If the time to rewrite or replace is 5x less than the "down time".. let sleeping dogs lie.. till they bite you in the arse.. especially if you plan on an upgrade in the near future. or as genius stated.. buy a non warrenty cheap replacement.