Hello everyone,

I've been working on mods to a RS500 program using ML1500. I didn't write the original program and have went brain dead. I have spent all day trying to change a few rungs on site with no luck.

If I attach the program or email to someone with a present and new sequence of ops, would anyone be willing to give input or assist me with the changes?? It only involves about 8-10 rungs of the program. I have to work all weekend so may be slow in resonding.

Any assistance appreciated.

Thanks

Attach it here to this post and write up what your trying to do. We will all help.


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Thanks so much. First, I'm only concerned with rungs 39-50. This is a turntable machine that sequences to the next position after cycle complete.

As you will see, the start sequence mooves the head of the position down to pick up a part while turning on vac to hold part
then the head moves back up
the head moves forward and then down to place the part turning off air to release part
1/2 sec delay and head goes back up
cycle is then complete to rotate table because head is up out of way.
head retracts to home position

NEW SEQUENCE DESIRED:

head moves forward holding part
head down to release partand drop vac
head back up and cycle complete to rotate table
head retracts
head goes down to pick up part starting vac
head back up
signal to start head forward for repeat of above.

Hope this makes sense;

The cycle happens in less than 2 seconds. The sequence is actually in rung order from 39 thru 47. Now they want rung 43 to be the first movement and go thru 47. Then go back to rung 39 output and finish up with rungs 40, 41, and 42. And the forward/retract and up/down solenoids and forward, retracted, up, and down proxes are affected. This appears to be where I am having problems.

Again, thanks for any inputs toy may have.

ok, i.ve spent less than a minute or so on this but maybe this is step closer to what you want.
rungs 39-47 seam to trigger each other so by just changing that, result should (could) be
more or less close to what you ask:

Yep, Panics sample looks good. Do you understand how he did it?

TW,

I have looked at it briefly since I'm working 12's at another site this weekend for a startup. Yes, I would like any comments you wish to offer. I know this is basic but I was missing something and frustration was setting it with the customer sitting beside me.

Also you or someone assisted me with the analog setpoints min and max and SCP to control a Powerflex VFD. The assistance has worked perfectly on two projects since.

I appreciate everyone's assistance and hope I will be able to do the same soon.

Thank you!!!!!!!!!!!!!!!!!!!

TW and Panic,

I guess I do still need some help. In rung 39, how can you put a n/o and n/c for same bit in the same rung?? Plus when it's started, what moves first---the forward???

Thanks,

Yes I would like some explanation help. For one I don't understand how you can use a n/o and n/c bit in the same rung 39;

Thanks,

ddevins

I don't think I understand the question. You can have a NO and NC in the same rung, if they had the same address and were in series then that could be a problem. Can you give the addresses of the instructions in question?

TW - If you look at the Rung 39 which Panic wrote you'll find an NO and and NC of B3:1/11 in series. Also once B3:1/11 is true on rung 47 how will the earlier rungs execute.

I propose the following revision. See if this is any closer to correct.

[attachmentid=2948]

My mistake, I was looking at the original program trying to find it

Wow, what ever happened to using Subroutines? Breaking this program up into subroutines would be beneficial to the troubleshooting group!

sorry i didn't answer sooner, it was a long weekend here and i was trying to relax.
i did check some messages but missed this forum...

you are right about NO/NC situation there but it looks like BoblFoot had time and energy
to look deeper into this problem. did you try his solution? it looks ok to me...


i know this is not your program but i must agree with snk, it's quite messy to see the
whole thing (regardless of size) in just one file. i would try at least organizing it a bit better
and prefereably - rewriting it completely. after all this program is very small (just some seventy I/O)
and i don't see any diagnostic, manual controls etc. it's a shame to lack all that since both
PLC and PV are already there. I looked at this one more time and i see that I:0.0/5 (welder ready)
is not even used in program. On the other hand there is something on I:0.0/10 but who knows what...
Then you have all this logic around T4:100 (reset welder) and yet the actual output O:5.0/3
to reset welder is not used!?

don't you fancy to make something more user friendly? it's always easier to troubleshoot
own code, but this is somehting you need to decide since this could cut both ways.
it will take some time depending on your experience.

i would consider writing it all new from scratch and organize it a bit better anyway
becuse if this stops and production is down, they will point finger at you anyway since
you ware the last one making change and fixing it then will sure add more pressure.
(now this is encouraging... ). if heat is up, maybe you could patch it up for now and
work on a future program. this way you would have time to think about it, add and enable
logic in stages etc.

there is some code that could be relocated to different files and "out of sight...".
for example bunch of timers confirming certain condition could be moved to one file.
operating mode selection could be in another, alarms in yet another, signals to and from PV
in another, sequence should be separate, calling all subroutines in another and same goes
for interlocks etc.

then making changes to sequence or rewriting it completely is only few rungs, because
program is modular and everything else remains the same. adding more modes of operation
allows for better control. i just love to add more options and ways to control equipment.
for example i routinely add step mode so if something does go wrong or need change
I can execute my sequnces step by step at my pace and see what really is going on instead of
drawing conclusions based on memory status after something (a lot of things) already happened.


just a tought...

Thanks for the vote of confidence. It has been quite a while since I wrote "unflexable" code like this. Usually I would have a rung containing a MUL B3:1 2 B3:1 and the conditions would be in that rung. To reconfigure the sequence is much easier when it is all in one rung.

I prefer sequencers. I know everyone either loves them or hates them

Put me in the category of never liked Sequencers, not to mention that they are "outlawed" by corporate standard at my current location.

Yes it is funny, some places require the use of them and some will tell you to take your equipment back with you if you use them.

Definitely, we have several sequence programs, but they are written without use of SQO, SQI, etc which as I said are illegal.

I'm not sure I like that but...

I would rather it spell out what it is so there is no confusion

But I guess that is why there are different methods of programming.

Hey TW just to illustrate our discussion, if time permits I'll rewite 39 to 47 using my multiply technique and you rewrite it using SQO, SQI and lets let folks compare and comment . If that doesn't confuse ddevins and he'd like to see both I'll find the time.

Actually why don't you make it a sample in the download section. I have a sample of a SQI, SQO sequencer in the download section I stripped out of a program for someone. I need to clean it up and describe it a little more but...HERE it is

THanks for the mental jog I did just that in a discussion of the Tank Program.