stretch wrap machine not working

[geniusintraining]

I have a customer with a simple stretch wrap machine that is not working, I have been trying to help them through email, the are in Brookfield, MO anyone in that area? this is taking way to long

It was stuck at the bottom and we got it to cycle, but now it goes from the bottom and cycles up one time and stays at the top, they can put it in manual and run it back down to the bottom, it should go up and back down depending on how many wraps they have selected, we only have a uploaded program, its a MicroLogix 1000 (l32BWA) I have added a couple of the inputs labels

Anyone know these machines? and want to take a stab? I will send this thread to my customer or if anyone is in Brookfield I can share your contact info

Thanks
Mark

 

[drbitboy]

Are one of the values of [I:0.0/2 Wrap at TOP] and [I:0.0/3 Wrap at BOTTOM] always 1, or can both be 0 at the same time?

 

[geniusintraining]

One thing I wanted to add, originally the machine would not do anything so I asked them to check input 3 becuase it looked like that was not made and needed to be, once they lowered it to make input 3 it started to work and thats when it would start and go up but never finish the cycle and go back down

I have a pic of the IO at the down ready state and will attach it once I get back

 

[geniusintraining]

Are one of the values of [I:0.0/2 Wrap at TOP] and [I:0.0/3 Wrap at BOTTOM] always 1, or can both be 0 at the same time?

I think you can only have one or the other, I think they are limit switches at the top and bottom

The attached pic is the state when nothing was working, hard to see but I think 1,2,3,4,5 and 9 are high, I asked about input 3 and they lowered it and thats when it would start but only go to the top

 

[drbitboy]

Also,

• Can you describe
  • the wrapping process,
  • what the operators control,
  • what the PLC controls?
• Can you describe what the inputs are?
  • I.e. process sensors vs. operator inputs?
  • I:0.0/0, and /1 are both labelled "Over Wrap;" what does that mean?
  • I:0.0/2, /3, and /9 and are labelled "Wrap at TOP,"Wrap at BOTTOM," and "Wrap UP/DOWN;" what does that mean?
    • Are those operator inputs?
    • Or perhaps indicators of the wrapper position?
    • I:0.0/8 is labelled "Start Cycle," so presumably it is a start button of some kind?
  • I:0.0/4, /5, and /6 seem to be part of a switch, and they assign counter presets (wrap count?)?
    • The value of /4:
      • is 0 for even presets, and
      • 1 for odd presets?
  • Although any of those counter presets assignments only happens if ...
    • ... I:0.0/7 is 0, so perhaps /7 is an NC button that triggers the update of those counters when pressed?
  • I:0.0/10 and /11 seem to be part of a switch that sets a Timer ON-delay preset.
• Can you describe what the outputs are?
  • O:0.0/4 is an OR-aggregate of several states; perhaps it is an indicator light?
• Can you describe what any of the internal bits (B3:m.n/k) represent?
• Can you describe what any of the counters represent?
• Can you describe what any of the TONs represent?

Other comments:

• The thirty-six instructions on six rungs 0008-0005 in LAD 7 can be reduced by nearly 60% and placed on one rung:
  • 
• Rung 0016 in LAD 7 can be simplified:
  • 

 

[drbitboy]

... I think you can only have one or the other, I think they are limit switches at the top and bottom

If [Wrap at TOP] and [Wrap at BOTTOM] are independent limit switches, and they cannot both be 1 at the same time, then it is likely that they can both be 0 at the same time, which would explain why B3:0.0/2, which seems to be (?) some kind of a RUN bit, drops out, i.e. becomes 0, and stops the process.

 

[I_Automation]

If [Wrap at TOP] and [Wrap at BOTTOM] are independent limit switches, and they cannot both be 1 at the same time, ..

If they are limit switches wired for safe operation of a cable breaks, as a lot are, then they would be wired through their N.C. contact and both would normally be on, only one turning off when the system is full up or down..


I always follow what I was told too-many years ago - current flow needed for operation.

 

[Jeev]

A shot in the dark...

If the machine has a home sensor, encoder, or counter on the rotating table/head then check that. If it is faulty or intermittent then it is likely that the banding sequence is not completing or counting properly and it doesn't get to the wrapping sequence.

 

[geniusintraining]

I always follow what I was told too-many years ago - current flow needed for operation.

Yes agree the IO labeled in the program was done by me so since this is being done via email I maybe wrong, the 'flow' from what I remember as I worked on a couple of them many years ago (25ish) the operator would set the number of wraps via a thumbwheel and select up or up and down, now I am back on a PC see attached pic of the machine

If anyone is in the area and wants to make a few bucks they would be happy to pay and get a troubleshooter in their pocket (everyone needs one)

 

[geniusintraining]

A shot in the dark...

If the machine has a home sensor, encoder, or counter on the rotating table/head then check that. If it is faulty or intermittent then it is likely that the banding sequence is not completing or counting properly and it doesn't get to the wrapping sequence.

I dont think it does most of these are just DC controlled that I have seen and they just use a limit with maybe a over limit for safety

 

[geniusintraining]

• Can you describe
  • the wrapping process,
  • what the operators control,
  • what the PLC controls?

• 
  
  I found this....
  Very similar but I think you get the idea

 

[L33er]

The overwrap inputs are for parts that need to be overwrapped either top/bottom or both.

A few bucks ain't enough for me.
Be a trans. and stand behind your work. Wait, did you say that was a few years ago? Be a man then.

 

[drbitboy]

What is the history of this code?

• Did they write it themselves?
• Has it ever worked?

Show me

 

[geniusintraining]

Be a trans. and stand behind your work. Wait, did you say that was a few years ago? Be a man then.

Really? Before last week I never talked this company, they contacted me and asked for help out of the kindness of my heart I am trying to help them, I am not charging them, they bought a PLC and a cable so I figured I would try and help, learn the facts before you make such accusations, yes 25 years ago I worked on a machine that was similar

My understanding it worked fine until last week, 99% sure its a input that has failed or out of adjustment

 

[rodneyhostetler]

Hello
i am the owner of the machine referenced to in this thread... i am posting 2 videos of the machine in operation as well as a video of the plc while it is making the cycle. i will be glad to answer any additional questions regarding how the machine works etc if you need it.

https://1drv.ms/v/s!AsRCLap1vyTSzQw-knNBqeIe3_9d?e=iDNmcL
https://1drv.ms/v/s!AsRCLap1vyTSzQuxoiueScWcZpdJ?e=u8mTzk