The depalitizing elevator of a local bottling plant stopped working, bringing production to a halt. The case of the non-lifting hoist.
Upon examination the ACES Control Systems Investigator found that the depalitizer hoist which lifts the bottles had quit functioning and the customer, thinking he could fix the problem himself, had swapped out the variable frequency drive with a VFD of a different brand. When too many wires left him confused he called in the expert Control System Investigator from ACES.
Working without a wiring diagram or documented PLC computer code, the CSI deduced that the IGBT driver controller card had failed and he could not examine the parameters for the drive.
The CSI reverse engineered on the fly and was able to locate an updated model of the original VFD. He purchased the parts and installed them. Five hours later the bottling plant was turning out fizzy soft drinks at top speed.