Applicable Systems
PLC
Symptoms
The PLC reports a CPU fault. The internal processor detected an internal error and halted operation to prevent unpredictable behavior.
Possible Causes
- CPU internal firmware error or corruption
- Watchdog timer timeout due to excessive processing load
- Hardware defect in the CPU module or memory
Troubleshooting Steps
- Step 1: Power cycle the drive to attempt a firmware restart
CPU restarts successfully after power cycle - Step 2: If the error persists, reload the firmware or replace the drive unit
New unit operates without CPU errors - Step 3: Check for excessive electrical noise near the drive installation
No significant noise sources identified
How to Reset
To reset: Power cycle the unit; if the error persists, reload firmware or replace.
Source: B&R Automation System Manual, B&R Industrial Automation
Category: PLC & VFD