timing off?

Hi Everyone,
I have an AB1200 running my dust collection system. I installed the program about 4 years ago and everything has been working ok. A few months ago the staff informed me the system was shutting down to quickly. I figured since no one change the problem the cause must be someplace else. If anyone has any comments your posts are appreciated.

Thanks,
Damian

If the timing is based on the Real Time Clock you may wish to check it and possibly reset it. It may have drifted from real time if it doesn't have an outside synchronization.

It's kind of hard to diagnose from what you've told us.

Define "too quickly"???

As others said, you need to be more specific. If you are running off of the time of day, or push a button and it runs for 1 hour.

Brijm said:

As others said, you need to be more specific. If you are running off of the time of day, or push a button and it runs for 1 hour.

Click to expand...

Thanks for the quick replies...
The problem is in the shutdown procedure.
Principals are:
blower1, airlock1, blower2, airlock2 and main blower

process
when the user presses the shutdown1(2) button, the blower1(2) stops within 5 secs then the airlock1(2) stops at 300 secs.

If both buttons (shutdown 1 & 2) are press the main blower stops at 360 secs

----

what is happening is blower 2 is shutting down at 30 secs after the shutdown button 2 is pressed.

Everything else seems to working ok. I have just barely enough knowledge in this field to be dangerous...


Thanks for reading and responding.

If someone is feeling really helpful here is a copy of the current .rss file. http://www.greatnortherncabinetry.com/ML120010012012.RSS

Thanks again

onyxtacular said:

If someone is feeling really helpful here is a copy of the current .rss file. http://www.greatnortherncabinetry.com/ML120010012012.RSS

Thanks again

Click to expand...

That did not work. Zip the file and post it here.

Greetings Damien. I looked at your website - nice looking work you guys do.

We can't access the file from your website. If you will post the file to this thread we can probably help you much more quickly. Right click on your .RSS file and pick send to compressed folder. That is what is known as zipping the file. You can then click the Go Advanced button below the message window and then scroll down till you see the attach files button. Browse to the zipped file you just made and click upload. It will then be attached to a post. From there we can take a look at it.

To me this is not a PLC problem, programs do not change on their own.

As the OP has stated nobody has changed the PLC program, and the shutdown procedure is running off internal timers not an internal clock, so in my eyes this must be a hardware problem.

I would be quite happy to look at the program.

Mark

Brijm said:

As others said, you need to be more specific. If you are running off of the time of day, or push a button and it runs for 1 hour.

Click to expand...

Thanks for the great response. I've added the file to this post.

TConnolly said:

Greetings Damien. I looked at your website - nice looking work you guys do.

We can't access the file from your website. If you will post the file to this thread we can probably help you much more quickly. Right click on your .RSS file and pick send to compressed folder. That is what is known as zipping the file. You can then click the Go Advanced button below the message window and then scroll down till you see the attach files button. Browse to the zipped file you just made and click upload. It will then be attached to a post. From there we can take a look at it.

Click to expand...

Thanks

I've uploaded the zip file.

The documentation is not good enough for me to tell which output is blower #2. Hopefully someone else can.
Do you know which output controls blower #2?

But if you look at the timer(s) preset values you can see there are no 300 sec timers. There are some 30 sec timers though.

See picture below.

How does the 30 second timer Outside Fan Alarm Start Timer T4:2(File 5 rung 0) get reset? Once the timer times out B3/32 will latch the rung on and it will never reset. Like Mickey, from the documentation that is there I can't tell what the purpose of B3/32 is but if that timer times out its /DN bit and B3/32 will latch on and stay on. Is there an HMI that resets B3/32? If not then that might be part of the problem.


Was this at one time a Micrologix 1000 program that was upgraded to a Micrologix 1200?

Damian,

I was going through your logic and trying to add Descriptions to the blank instructions. I found a severe error on File 6, Rungs 2 and 5. You have used B3:3/3 OTE two times - the double-coil error. Only the last case of B3:2/2 (Rung 5) will have control. Best I can tell, B3:3/3 is "AIRLOCK 1 ON". Maybe you had two airlocks and have combined them into one? In any case, some changes need to be made here.

In general, this program is very loose, like a dog chasing its tail, has a lot of unnecessary rungs, and could be made much simpler.

Outputs in Program:
O:0/0 Outside Blower 1
0:0/1 Airlock Out 1
O:0/2 Outside Blower 2
O:0/3 Alarm Light 2
O:0/4 ???
O:0/5 ???
O:0/7 Alarm Light 1

Airlock Out 2 seems to be missing in the program. In your earlier post, you mentioned Airlock 2. How is it controlled? Is it one of the unlabeled outputs?

when the user presses the shutdown1(2) button, the blower1(2) stops within 5 secs then the airlock1(2) stops at 300 secs.

Click to expand...

I cannot verify that Blower 2 (O:0/2 on Lad 5, Rung 6) stops within 5 seconds. It appears that Timer T4:8/TT keeps it running for 600 seconds. I think you said it "reversed": On Lad 3, Rung 7, Timer T4:6/TT Cycle Off Sequence Timer keeps Airlock Out 1 on for 5 seconds after Stop Pushbutton is pressed.

I think you meant this: "When the user presses the Shutdown 1 (I:0/1) or Shutdown 2 (I:0/2) button, the Airlock 1 or Airlock 2 stops within 5 secs, then the the Blower 1 or Blower 2 stops at 600 secs."

If you would answer a few questions, this program could be rewritten and shortened down about 50%!

O:0/0 Outside Blower 1: What starts it up, and what shuts it down, and what timing functions are involved?

O:0/2 Outside Blower 2: What starts it up, and what shuts it down, and what timing functions are involved?

0:0/1 Airlock Out 1: What starts it up, and what shuts it down, and what timing functions are involved?

0:0/? Airlock Out 2: What starts it up, and what shuts it down, and what timing functions are involved? Has Airlock Out 2 been eliminated and combined with Airlock Out 1?

O:0/3 Alarm Light 2: What alarms does this light indicate?

O:0/7 Alarm Light 1: What alarms does this light indicate?

since you are using timers in the plc program, I would edefinatelly check if some control panel hardware is tripping (externally) before you change your plc program, PLC timer values are stored in registers and don't change by them selves. if the staff is telling you the system is shutting off too quickly, maybe an Overload is tripping.

I recommend you get an electrician to check the panel and / or motors, etc before making any PLC changes, specially because you say the system was working fine for a long time...why would the PLC be responsible ?? it hasn't change...there must be a hardware failure!

hope this helps
Kyle Sleiman