The Case of the Missing Parameters

THE MYSTERY

The ACES CSI was called to the scene of a factory that manufactured cardboard boxes. Two of 24 drives controlling a folding and gluing machine were down and there was an error code on the front of the amplifier that indicated “the operating parameters were not loaded correctly.” The plant operators weren’t using the particular component controlled by the drives, so the CSI worked in the midst of a plant in full operation, balancing over an active light curtain to access the balky servo drives.

THE CLUES

The plant maintenance foreman gave the CSI an outdated software manual, complete with floppy disks — which, needless to say, were of little help.

He needed to unarchive and reload the parameters — but didn’t know which drive was faulty; none of the 24 drives were labeled. The CSI started by unarchiving and reloading all the drives at once as an automatic process, with no discernable results.

The only other option was to unarchive and reload the drives one by one. The CSI made another call to tech support, who said “I think that’s maybe drive number 30 in the 2000 module.”

In spite of the unorthodox numbering system, and there being no drive 30 in the documentation, the CSI was finally able to identify disc 30a and drilled down 15 screens deep to find the archived parameters. Upon further study, the CSI discovered that the missing parameter controlled the angularity of the component that folded a small auxiliary flap. A machine can’t fold if it doesn’t know the angle it’s folding at.

THE PERP

The CSI explains, “The customer had turned the power on and off quickly — so quickly that the drive didn’t have time to wind down, and then you hit it with new surge. You should turn it off and let it set for a minute or two to let all the RAM die.” The rapidly fluctuating power caused the servo drive to have a senior moment.

THE SOLUTION

Drive 30b was just waiting on input from 30a, and they both came back online, error-free, once drive 30a was unarchived and restored. As a test the CSI turned off the drive and asked one of the operators to turn the shaft. Then he hit “reset” and the shaft went around and came right back to its home position.

Now all components of the customer’s machine are folding and gluing corrugate sheets into finished boxes with no problems.

CASE CLOSED