Good news, Pat.
TGIF... the end of the week from HELL.
I was gone last week on a service call to Indiana. On the day I left, my local customer called and told me their large rod-breakdown machine went down. I told them I'd be back on Saturday, and could look at it then. They insisted they couldn't wait, and would have their maintenance guy look at it.
He did more than look, alright. In his messing about in the spooler sub-panel, he managed to jump 480 volts AC to the 24 volts DC system for all the electronics. He smoked just about everything electronic in the machine. It took me all week to locate and replace all of the damaged components, at a cost to the customer of over $24,000- not to mention the downtime on a machine that feeds every single other work station in the plant.
The final tally:
1 S7-300 CPU
2 32 DI cards
2 16 AI cards
1 16 AO card
12 Phoenix Contact level converters
11 4-20mA proximity sensors
38 proximity switches
11 Siemens MasterDrives input boards
35 24v lamps
16 24v relays
I suggested to the customer that next time... waiting the two days would not be such a bad idea, after all. The original failure was a stuck relay that made a small motor blow a fuse. The function for this motor was to run the elevator that loads spools; something that can be done with a forklift, in a pinch. It would have been a 15 minute repair to replace the relay and fuse. :roll:
Here's the inside of one of the input cards.