The PLC Never Reprograms Itself
The other week, our product autostrapping system went haywire. One of its sequences got mixed up and and was doing it 'before' instead of 'after'. The strap bayonet (a channel that extends underneath the product to provide a pathway for the strap and then feeds before tightening it, retracts then position itself unto another side for another strap) was extending all the while it is moving to another position resulting in the bayonet hitting the product and getting bent and shearing its bolts.
Since the the system was run by a programmable logic controller, a group of maintenance personnel decided to disable one output bit as they are concluding that there was something wrong with the program. It made the machine run like normal though. But one colleague and I was thinking otherwise (me and that guy is not assigned for that problem, we are working somewhere else).
The Value of Knowing...
The other day, I sent off one of my electrical technician colleage to some breakdown on one of our company multi-purpose industrial cranes. One of its specialized hoist is not working and is unable to lift its load. Immediately he sped off to the scene and few minutes later came back.
I asked him if the problem was already rectified and he said yes and the production people are already using it. I ask him what he did to fix the problem and promptly replied with another question if I had raised a workorder for it. I said yes and ask him why he'd ask and if he did something to make it okay and working.
He answered that it was just a small thing and no need to raise the work order as it would be a 'hassle' of making report and closing the said workorder. He said only resetted the circuit breaker that tripped due to some insulation fault. That fault always comes when the hoist comes in contact with the earth ground which is quite common in our case.