Force it on, latch it out, or shut down and fix it??

[just the cowboy]

Ten guys with laptops

I had ten guys that worked for me in a plant and they all had laptops. This was back before any software managed checks and things were saved to floppies. We had a rule if you changed ANYTHING in a program you put it in writing.

Who did it?
Who asked for it to be done?
Why YOU did it.
How long is it going to be that way?

If we went to work on a machine and it had a force on it if it was not TAGGED on the controller forces were removed.
If you went to work on a machine and the backup did not match the machine and there was not a temporary floppy at the processor you reinstalled the backup program.
Backup floppy’s ONLY had working programs not any temp fixes.
When you had 100+ PLC 2s and PLC 5s and SLC500s you could not put in patches and expect them to be taken out all the time. So it was no permanent patch for more than 2 weeks.

 

[dwoodlock]

I think in this world of JIT manufacturing, the pressure to put band aids on things increases more and more.

I subscribe to the philosophy that anything worth doing is worth doing right. This isn't always the popular approach, but **** being popular, this isn't highschool.

My biggest issue with band aid fixes is that once its ok once, it then quickly snowballs into being ok in 500 other instances. You then establish a culture where band aid fixes are the norm, and you train new people to do jobs and they only ever see a band aid fix, so they never learn how to fix the issue correctly.

I have quite a few workplace disagreements related to this topic....

Best of luck.

 

[MitsM83]

Here is an example of the type of thing I am referring to.
My widget maker was running two widgets, they run side by side on to a table where a manipulator picks them up using vacuum. A couple prox switches on either side of the table verify part presence and send the manipulator down. We were 30 min from shutting the entire plant down and had an hour worth of widget material that was bowed out just enough to not pick up on the left part present switches. Can not get new material till tomorrow and gotta have these parts tonight or shut down the plant.

I wrote that if right part is present so is left. The vacuum cups on the manipulator have a switch so it wont go up unless it definitely has a widget.

 

[cmothebean]

I have never used forces. Instead we use a bit called BRIDGE which can be easily cross referenced. If we need to go around something we required approval and will conduct a short risk assessment. I will generally write around it in the code and someone will often man the equipment until scheduled or opportune maintenance occurs.

We have had serious incidents from bridges being left in the code years ago. You need to keep track of them with some paperwork, a regular audit, stick notes, reminders in your calendar, writing it on your hand...

 

[Steve Bailey]

Sounds like an example of fixing a mechanical problem in software. The real problem is that the left part present sensor is incorrectly adjusted. Why didn't you fix that instead of modifying the program?

 

[MitsM83]

Sounds like an example of fixing a mechanical problem in software. The real problem is that the left part present sensor is incorrectly adjusted. Why didn't you fix that instead of modifying the program?

The adjustment is correct it is flush with the top of the plastic block it is in cased in, any higher it will get the top chopped off of it. You are however partly correct. The mechanical issue was the bowed material.

As I mentioned the only alternative was shutting the plant down. Which I would have done had it been a safety device or something that could cause serious machine damage.
I have recommended getting some sensors with a slightly further range.

If we have enough of that widget made to continue running something else until we can get better material we do.

When I do things like this I am using internal relays assigned to me. They show up in the weekly back up and verify that is automatically done and then emailed. Not to mention the work order I fill out the operator report and if it's going to be in there longer than a week which this is not I would fill out a spreadsheet that gets mailed to all who are concerned.
This problem and someone's lack of dealing with it is what raised the question in the first place.

 

[osmanjdt]

I had ten guys that worked for me in a plant and they all had laptops. This was back before any software managed checks and things were saved to floppies. We had a rule if you changed ANYTHING in a program you put it in writing.

Who did it?
Who asked for it to be done?
Why YOU did it.
How long is it going to be that way?

If we went to work on a machine and it had a force on it if it was not TAGGED on the controller forces were removed.
If you went to work on a machine and the backup did not match the machine and there was not a temporary floppy at the processor you reinstalled the backup program.
Backup floppy’s ONLY had working programs not any temp fixes.
When you had 100+ PLC 2s and PLC 5s and SLC500s you could not put in patches and expect them to be taken out all the time. So it was no permanent patch for more than 2 weeks.

Wasn't me.


https://www.youtube.com/watch?v=SlKHIzOeZO0