Case №08 · Remote diagnostics
One month of downtime – caused by a single relay contact
Remote diagnostics on a Schneider PacDrive packaging machine: after roughly one month of downtime, the cause was found in about two hours — an incorrectly wired contact on relay KA20.
Task
After a servo drive had been replaced, a packaging machine with Schneider PacDrive would no longer start. The customer and electricians spent about a month searching for the fault, and the manufacturer connected remotely twice. Drives, power supply and wiring were checked without finding the solution. The task was to identify the start interlock systematically without replacing further healthy components.
Technical data
- Schneider Electric PacDrive
- Lexium LXM62
- SoMachine Motion Logic Builder
- PLC logic
- Live-signal diagnostics
- Contactor feedback
- Relay KA20
- 100% remote diagnostics
- Approx. 2 hours diagnostics
Work performed
- Remote connection to the Schneider PacDrive controller and work with the original project
- Analysis of live signals, interlocks and PLC logic in SoMachine Motion Logic Builder
- Comparison of program states with the electrical diagram and contactor feedback signals
- Localization of an incorrect feedback signal from the power contactor
- Inspection of relay KA20, which had previously been replaced
- Identification of a normally closed contact wired instead of the required normally open contact
- Rewiring to the correct contact followed by a functional test
Result
- The fault cause was clearly localized in about two hours of remote diagnostics
- The fault disappeared after the contact wiring was corrected
- The machine started immediately after the correction
- No further unnecessary replacement of healthy drives or components was required
- A month of downtime ended by correcting a single feedback-contact wiring error