stretch wrap machine not working

[rodneyhostetler]

What is the history of this code?

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

Show me

the machine was working great until we had a power/surge and outage in the building - it has not worked correctly since then. the machine mfg would have done the code as far as we know but their support is horrible and i have been waiting over a month on them and still have no answers which is why we are taking matters into our own hands to try and figure it out - whatever it takes - we need our machine as a new machine is several months out minimum...

 

[L33er]

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

LOL, I got you on hook that easy!

 

[L33er]

Well Rodney, looked like you are smart guy, being able to upload a video. You should be able to figure it out yourself. It's a simple machine.

Do you have a schematic? or a program with description?

If not, do it the harder way:

First, put it in the manual mode and have a helper to look at the input lights while the second person activate the switches manually. Record what those switches are. Especially, the whisker one on top.

 

[drbitboy]

the machine was working great until we had a power/surge and outage in the building - it has not worked correctly since then. the machine mfg would have done the code as far as we know but their support is horrible and i have been waiting over a month on them and still have no answers which is why we are taking matters into our own hands to try and figure it out - whatever it takes - we need our machine as a new machine is several months out minimum...

What @L33er said.

@geniusintraining is almost certainly right: one of the discrete inputs is either failed or otherwise not behaving properly. If you have, or can get, a maintenance electrician onsite, they should be checking the thirteen inputs and five outputs.

The code is bit of a dogs breakfast (hot mess). Since the machine did work before, the code is probably not the source of the problem, but it does make diagnosing the problem more difficult.

If you got someone to come in I suspect that it would be for not less than 8h at some rate (e.g. 250$/h ±100%/50%). You probably have at least one PM (Private Message) in your forum Inbox (see the Private Message: Unread n, Total n. link near the top right of this page).

If not, try searching for system integrators (e.g. see here).

 

[drbitboy]

found this: https://utsitech.com/contact-us/


and this: https://utsitech.com/services/stretch-wrappers/itw-mima/

 

[rodneyhostetler]

Well Rodney, looked like you are smart guy, being able to upload a video. You should be able to figure it out yourself. It's a simple machine.

Do you have a schematic? or a program with description?

If not, do it the harder way:

First, put it in the manual mode and have a helper to look at the input lights while the second person activate the switches manually. Record what those switches are. Especially, the whisker one on top.

unfortunately we have no documentation whatsoever on this machine which is a huge pain!

we already did some of that...
input 9 - if off the switch is on "wrap up" if on the switch is on "wrap up/down)

on the overwrap switch it did this - if turned to off the output 0 is on, if turned to low no outputs if turned to high output 1 is on

input 2 is our top limit switch

input 3 is our bottom limit switch

does this help? i have never seen plc code before so it is all new to me unfortunately but i am very techy i am starting to wonder if there is a sensor on the turntable that counts how many rounds it makes that is not registering... would that be the next thing in the code sequence maybe?

 

[rodneyhostetler]

What @L33er said.

@geniusintraining is almost certainly right: one of the discrete inputs is either failed or otherwise not behaving properly. If you have, or can get, a maintenance electrician onsite, they should be checking the thirteen inputs and five outputs.

The code is bit of a dogs breakfast (hot mess). Since the machine did work before, the code is probably not the source of the problem, but it does make diagnosing the problem more difficult.

If you got someone to come in I suspect that it would be for not less than 8h at some rate (e.g. 250$/h ±100%/50%). You probably have at least one PM (Private Message) in your forum Inbox (see the Private Message: Unread n, Total n. link near the top right of this page).

If not, try searching for system integrators (e.g. see here).

thanks for your insights - i do not have any PMs yet but will keep watching... i will get my electrician back and do some more troubleshooting to see if i can get any closer to the problem with all that i have learned from everyone
Thanks

 

[BachPhi]

Your issue is the whisker switch (I2) at the top. It' s stuck.

It should be activated once to stop the cycle and spring back to its position which will switch to the Down direction (O3).

Remove the switch, then let the cycling up, then hit the switch once and let it spring back its position, it should switch the direction.

 

[Hoggin]

Check to see if there is a limit switch or prox. switch under the turn table. We used to have some older ones that had a limit switch under the table that would count the revolutions when the carriage was at the top and bottom. The carriage is stopping so that tells me the top limit switch is working.

 

[rodneyhostetler]

Check to see if there is a limit switch or prox. switch under the turn table. We used to have some older ones that had a limit switch under the table that would count the revolutions when the carriage was at the top and bottom. The carriage is stopping so that tells me the top limit switch is working.

thanks - we are checking that now

 

[plvlce]

Check to see if there is a limit switch or prox. switch under the turn table. We used to have some older ones that had a limit switch under the table that would count the revolutions when the carriage was at the top and bottom. The carriage is stopping so that tells me the top limit switch is working.

This seems like a productive train of thought. We can see the selector switch value is read in as a binary value via inputs I:0/4 through I:0/7 and if it is 1-6 inclusive it then sets counters C5:2 and C5:3 to the appropriate value (each of which has one of the limit switches as an input condition).

For troubleshooting, the basic process to start with is to ask 'what did happen correctly', 'what did not happen', and then 'what input(s) does the program expect to trigger a transition from the first to the second?'

The upward motion does stop, so we can presume the upper limit is functional. It then does not go downward, so we ask 'what triggers it to start downward motion?' Since we see that you select a number of wraps done at top (and bottom), we presume that the downward motion should start once those are complete. So how does the program know when the wraps are complete? Look for the sensor.

I'm going to *guess* it's wired to I:0/9 as that is used to trigger B3:5/1 which is used in the counter logic. Seems like it should go on and off to increment the counters as the table rotates (as Hoggin describes), but in the video of the PLC LEDs I don't see it changing.

 

[BachPhi]

I agree. The video shown the wrap pattern selector at =9, yet only seen I4 & I5 on which is pattern 3.
Based on the program & the labels on the enc. , valid patterns are from 1-6.
Test the thumbwheel selector:

Set at 1 - I4 ON
Set at 2 - I5 ON , I4 OFF
Set at 3 - I4, I5 both ON
Set at 4 - I6 ON
...

Was the program uploaded from the PLC? or is it from an old copy ?
Something not right, where both I4, I5 are on then B3:5/0 is OFF then how can they be in the cycle?

 

[plvlce]

I agree. The video shown the wrap pattern selector at =9, yet only seen I4 & I5 on which is pattern 3.
Based on the program & the labels on the enc. , valid patterns are from 1-6.

9 is the selection to move it down manually, which the operator does in the video after stopping the machine but before the camera pans to show the selector.

There's no method of zeroing the counters, so a value other than 1-6 on the switch should effectively leave the last valid value in the counter (either 1 or 6 because of how the selector switch works)

I do not think the two videos were taken simultaneously, so I would not trust that the selector value of 9 shown would match the value when the video of the LEDs was taken.

 

[rodneyhostetler]

i am so happy! the sensor that counts the rounds on the turn table was our problem... thank you to all who contributed!! we greatly appreciate it!!

 

[geniusintraining]

i am so happy! the sensor that counts the rounds on the turn table was our problem... thank you to all who contributed!! we greatly appreciate it!!

As the saying goes.... "it takes a village"

Good job everyone and a extra star for Hoggin