Help with STL in Siemens Step 7 Classic... with video and attachment.

[drbitboy]

Just to add some realism to the situation, here is a video clip of the machine with the pulsing output: https://youtu.be/g80TO8BAyqA

So I would guess MW82 is the position of that tray; back towards the camera is ~80; when slid forward it is ~1020.



It looks like the condition [M37.4=1] slides that tray forward, but the tray drifts back a bit on the condition [M37.4=0]. If that drift back is slight enough to not be a problem, then disallowing M37.4's value to become 1 because of [> DB60.D_11 MW82] again until the tray drops back to the beginning (say MW82 > 200) might be the solution.

P.S. I think the sign on EPSilon, or perhaps the seal-in placement, in my earlier sketches was inverted.

 

[AutomationTechBrian]

Ok, I think we figured out the problem... It's a mechanical problem. The feedbox moves forward to exceed 1020 and hold for 2.5 seconds (set at the operator station HMI). There is a leak that causes drift-back, which re-activates the GT 1020, and it continues for 2.5 seconds, after which it continues to the full forward position, then returns to the base address. (Yes, I found that MW 82 is a position, not a timer.)

Thanks for the input, guys! Pointing out the comparison of D_11 to MW 82 was the seed of info that ended up solving the problem.

 

[drbitboy]

Thanks for the input, guys! Pointing out the comparison of D_11 to MW 82 was the seed of info that ended up solving the problem.

LOL.

Where do we send the invoice ?

but this STL network is long, and it's taking me far to long to pick it apart.

But seriously, what would happen if you asked the plant manager to allow you a couple of days to fully document this process and add comments to the STL code, even if you only did it on paper? So the next time summat is amiss, you don't on a goose chase about the PLC program is causing the problem?

How long has that symptom of the leak been there?