Hi,

I would do a firmware update of PLC and your AQ Modul. If it´s 6ES7232-4HB32-0XB0 newest FW is V2.1.1 > you get it there:

Firmware update for S7-1200 Analog Output SM 1232, 2AO

Following changes:

HW component Update without function change to improve module Electromagnetic Compatibility

Regards,

Towome

Place an accelerometer on the enclosure containing the PLC and module(s) creating the PLC diag buffer error entries.

Measure the g's during the press machine cycling.

If it is significant, perhaps consider adding some locking terminals on the DIN rail holding the PLC and modules to prevent them from vibration loose.

If you can, move the enclosure away from the vibration, but if you cannot, consider inserting elastomers between the enclosure and whatever it is mounted.  Using the accelerometer and FFT to analyze the data, you can see what frequencies need suppressed.  Then you can purchase elastomers meant to suppress those frequencies.

You can also insert thick rubber washers between the DIN rail and back panel where the screws go through to absorb some of the mechanical shock and vibration.

Does the error automatically reset, or do you have to login and manually restart the PLC, or power cycle everything before the error will clear?

If the error automatically resets, and it does it fairly quickly, you might consider - as a temporary measure only - using interrupt OBs to catch these errors.  In this way, you can tell the PLC to temporarily ignore the fault but only for x numbers of msec.  After that, if the fault has not cleared, then create a fault within the PLC logic and halt the process.

I could be completely wrong, but the provided clues seem to indicate a vibration problem.

sean_mmsni

I have a PLC running a large press machine. It ran perfectly at the start and then it began to every so often it would go into error mode and stop. It was happening say once a month. Now it is happening more and more frequent on a daily basis now. It is holding up the production badly now so I need to sort it.

I have looked through the error log and it seems to think one of my expansion modules is being unplugged during the cycle. However I have checked everything is plugged in correctly and unplugged and plugged everything in again. The PLC is in a large metal enclosure so is well protected.

I have attached the most recent error log. It also states that the AQ board is losing voltage during the cycle. I am guessing these two errors are directly linked. 

Does this mean my plc / expansion modules are faulty?  Is there any other checks I can do or anything else that could be causing these errors?

Would greatly appreciate your feedback as I am at a lose end and don't want to buy new plc/expansion boards if it is not needed.

If anti-vibration mounts helps, I strongly recommend relocating the enclosure off the frame of the controlled system, perhaps on separate feet supported by vibration pads meant to absorb the vibrations of hydraulics and other strong physical cyclic loads.

In my work past, some equipment required multiple isolation in order to function properly.  Isolating feet for the legs.  Pads under an isolated pad, and pads under the instrumentation.

To convert that to your project, it might mean isolation from the equipment with flexible conduit rather than hard-plumbed conduit, isolation cable loops rather than strapped / bound cable bundles, and inside the electrical enclosure, rubber pads beneath the mounting sub-panel, and also between the DIN-Rail and the sub-panel.

If it solves the problem, it's worth the extra time to ensure it makes it past warranty!!  Plus, it really helps with the company reputation to solve hard problems with seemingly simple solutions.

There are companies that specialize in providing the right isolating elastomers and tips on how to determine the right frequencies to absorb (isolate).

I have an app on my phone that measures vibration, and displays the results in the freq domain using FFT.  Very good at finding the main frequencies to absorb.

sean_mmsni

Thank You, when the plc goes into error mode I have to reset it manually or else do a complete power down and power up again and that clears it. I have since added rubber anti vibration mounts and so far so good, however the machine hasn't been run at full production yet so I cant say for sure.