Program running extremely slowly in Logix/Studio 5000

[mylespetro]

Hey everyone,

Recently converted a PLC-5 program to ControlLogix (initally to V20.19, just changed it to V24.11), and I'm experiencing extremely slow browsing of the project when online in Logix, both RSLogix 5000 and Studio 5000. The program itself seems to be executing on average in just under 10ms, as indicated by the info window under the controller organizer when I highlight the program task, but it can take anywhere from 20 seconds to a minute to change between different routines. This is regardless of connection type, whether hardwired Ethernet or USB.

The I/O is handled through Remote I/O on a DHRIO+ card, but even if I inhibit the module, the lag remains (no I/O connected at the moment, just doing a bench test at my office).

It doesn't happen with any other programs, even much larger programs with way more rungs and routines, and it certainly isn't my computer (new i7 CPU, 32GB ram). The only thing I can think of is that some part of the program is causing it, but I can't really figure out what it is. There's a decent amount of JSRs with input and return parameters, but even if I AFI those rungs, it still happens.

Just wondering if anyone has any insight as to what could be causing this issue, as it will make commissioning the system borderline impossible.

Thanks

 

[travispedley]

I remember V24 as being a bug filled nightmare. Just for grins, have you tried exporting to L5K and creating a new program with it? Or changing to a more stable version of Logix (32+ have been solid for me so far)

 

[mylespetro]

I remember V24 as being a bug filled nightmare. Just for grins, have you tried exporting to L5K and creating a new program with it? Or changing to a more stable version of Logix (32+ have been solid for me so far)

I've personally had no issues with V24 over the past several years, but I haven't tried a higher revision. I did do the L5K trick to change the revision from V20 to V24, but the fact that it acts the same in both revisions makes me suspect it may still happen in V32 regardless. I'll give it a try, but I have to download and install V32, which will take a while on the ancient DSL internet at our office. I actually had intended to try V34, but realized just before I flashed my bench test processor that I don't have V34 of Studio installed. If I manage to get it all swapped over to 32/34 I'll come back with an update.

Thanks for your input

 

[Mispeld]

If it's an older logix processor, and running over-scheduled periodic task(s), there could be a shortage of time for communication overhead. There's a task monitor tool that could provide insight. If there is only a single, continuous task, this would unlikely be the issue with online programming response.

 

[mylespetro]

If it's an older logix processor, and running over-scheduled periodic task(s), there could be a shortage of time for communication overhead. There's a task monitor tool that could provide insight. If there is only a single, continuous task, this would unlikely be the issue with online programming response.

There are two or three scheduled tasks, just by default of the way the conversion utility (don’t crucify me lol) works. It creates one task (“2_MAIN_”) that just has an event trigger which jumps to the next task which actually houses the program logic. Maybe I’ll try moving all of the logic to that MAIN program and try switching between periodic and continuous and see if there’s any difference.

Thanks!

 

[mylespetro]

I put all of the subroutines into the continuous "MainProgram" task, and everything is working as normal now. I find that strange, because several other programs converted the same way have the same structure (continuous "MainProgram" with an EVENT instruction calling a periodic "_2_MAIN" task) and I have no issue browsing those while online.

I'm actually fine having it all running in the continuous task, the separate periodic task seemed a bit extraneous when the only thing in the continuous task was to call the periodic task anyways.

Thanks for the tip Mispeld, I should have thought of trying that in the first place, but as I said, the same structure doesn't seem to hamper any of my other converted programs.