PLC5/40E to PLC5/80E

All,

I have a 5/40E that the memory is full on. For an easy fix i would like to just put a 5/80E in it's place. I know that these are going out the door, but it would be a quick change over for little money since I already have one. What I'm wondering is what can I expect it to do with the scan time. The scan time isn't really a problem, I am just wanting to make sure that I would get a better scan time out of the swap. I also plan on adding some preventive maintenance timers and I think that the 5/80 will do all I need without having to swap the whole system over to CLX.

I said earlier that the scan time isn't a problem, but I'm not for sure on that either. Right now it has about 175 word free. That's just because I deleted some old stuff so I could make on-line edits. It is on a DLI (Double Length Infeed) for a sawmill. I know a faster scan time can't do anything but make it better. It does a lot of motion control and I plan on upgrading to CLX someday, just have too many projects going right now to tackle that.

The different PLC-5 Enhanced, Ethernet, and ControlNet controllers don't have different CPUs and clock speeds, only different memory sizes and I/O capacities. All of them specify 0.5 ms/k average instruction execution.

But I remember some issues from a decade ago where the PLC-5/80 could actually be slower than its siblings because some instructions were moved to firmware instead of the various ASICs in the controller in different Series hardware. The issues depended on what instructions you were using.

In summary: Your PLC-5/80 won't be any faster, but it might be slower. Try to get a newer Series of PLC-5/80 and run this issue by RA Technical Support.

That seems like a lot of memory for the machine. Are you sure the code is optimized?
I think the scantime will be the same but the experts can confirm, and this may be series and FRN dependent.

Can you post the program and the I/O layout (or make sure the documentation part in the file is accurate)?

If you already have the PLC5-80 and can spare a few minutes and run some tests, you can probably find out without a problem. Just monitor the scan time before and after the swap.

I am pretty sure all you have to do is save the file with a new name, change the processor type, and save it. I normally do clear the I/O image but I don't allow it to resize data tables because I have already chosen my spares) When you download, it might be wise to clear the new processor memory first.

Make sure to keep a good battery in the old one, so you can plop it back it if you run short on time or something goes wrong.

EDIT: Ken is the authority, and his post reminds me of an experience at my previous employer by another team who ran into a scan time increase when upgrading so I can confirm that possibility.

Quick tips for getting more memory

Here are some quick tips for the PLC-5 platform.

1) Reduce file size: It was typical for programmers to be all over the map with their data. This is really problematic with memory intensive data types like FP PID. For example if you've got 1 timer in your PLC, T4:999 you've used up 3,000 words of memory.

2) Move Data and Program files to lower numbers. Each unused data file and program file eats 6 words of overhead. For example, a program, empty except for subroutine 100 will cost (a little less than) 600 words because the controller reserves 6 words for all of the program files from (1?) 3-99. Simply moving the subroutine to a lower number (and of course changing the JSRs) will also save you memory.

If you've got either of these situations then you could significantly reduce your memory usage without buying a thing and with relatively little pain.

...and there's always TOPDOC (anybody have any experience with it?)

Good luck,

(8{)} .)
(Yosi)

Yes TOPDOC cheap to!

http://www.softplc.com/oldtopdoc.php

Surprised this is the first time on this site I have heard about them. My old company I worked for 7-8 yrs ago we used a few of them and inherited a few more. I sat down with a sales rep and a coder for a few days to get up to date on them and we had a few applications that needed direct serial communication to a electronic preset.. The open architecture alows development for C/C++ or Java and the use of there COMGENIUS lets you use the com port right on the plc to talk to what ever you can code.

The software was designed ( from what I was told ) by developers that used to work for ab developing the rs5 5000 software and developed this platform on the same guidelines as ab. I used the conversion tool as well and worked seamlessly. The only draw back is with the Tealware line there is no online editing. Last time that I know of.
that was a big deal breaker for a lot of the applications we had. There was no such thing as down time.. But it has its advantages as well.

On the subject of other vendors software has any one ever heard of UCOS.

Yeah, I looked at this website to. The conversions looked interesting, but I'd rather stick to a bigger company like RA and use their conversion tool or do a rewrite. I don't know why anyone would use C++ for PLC control, unless its for small math routines. Online programming is a must in my work, especially for big systems. Downtime to do downloads is hard to come by.

Thanks guys! I talked with my AB rep. and he confirmed that I would get more memory but the scan time wouldn't change that much. The scan time wasn't a problem anyway. I did go in and delete some old code to free up some memory and buy me some time. Thanks for everybody's replies, I plan on using this site alot more than I have in the past due to a job change and the wealth of information that is here. Again thanks and everyone have a GREAT evening!!!