Applicable Systems
EFC
FEX
FEI
HNC
Symptoms
PLC runtime error. The drive's internal PLC (soft PLC or IEC 61131-3 logic engine) has exceeded its runtime budget. The motion task did not complete within the allocated time slice.
Possible Causes
- PLC program too complex for the allocated cycle time
- Too many motion tasks or axes being controlled simultaneously
- PLC program contains infinite loop or blocking call
- Runtime cycle time set too short for the program complexity
Troubleshooting Steps
- Step 1: Check the PLC runtime cycle time setting in IndraWorks AS
Cycle time adequate for the program size and complexity - Step 2: Profile the PLC program to identify time-consuming function blocks
Optimize or simplify the most time-consuming code sections - Step 3: Reduce the number of simultaneously controlled axes if possible
PLC can handle all axes within the cycle time budget - Step 4: Increase the cycle time if the program complexity cannot be reduced
New cycle time accommodates the program execution time
How to Reset
1) Connect IndraWorks AS. 2) Check PLC runtime statistics. 3) Optimize program. 4) Adjust cycle time. 5) Reset fault.
Frequently Asked Questions
- Q: What is the internal PLC in IndraDrive?
IndraDrive can run IEC 61131-3 soft PLC logic internally, eliminating the need for an external PLC in some applications. The logic runs on the drive's control board.
- Q: How do I optimize PLC runtime?
Avoid blocking calls (wait statements), minimize floating-point operations in tight loops, use structured text efficiently, and distribute tasks across multiple cycles if possible.
Source: Rexroth IndraDrive HCS/HMS Fault Code List, Bosch Rexroth AG
Category: PLC & VFD