Replaced encoder cable with double-shielded LiYY-CY, connected shield to both ends (encoder housing and controller PE). Error eliminated.
| Code (Dec) | Code (Hex) | Error Name | Description | DIOP indication | Recovery | |------------|------------|------------|-------------|----------------|----------| | 1000 | 0x03E8 | Overcurrent (phase) | Phase current exceeds 5 A peak | ERR LED: 1 blink, DO3=1 | Cycle power | | 1001 | 0x03E9 | Short circuit output | Short between motor phases or to GND | ERR LED: 1 blink, DO3=1 | Check wiring | | 1010 | 0x03F2 | Overvoltage (power) | DC link > 56 V (48 V nominal) | ERR LED: 2 blinks | Reduce braking energy | | 1011 | 0x03F3 | Undervoltage (power) | DC link < 18 V | ERR LED: 2 blinks | Check supply | | 1012 | 0x03F4 | Logic undervoltage | 24 V logic < 19 V | ERR LED: 2 blinks | Stabilize 24 V | | 1020 | 0x03FC | Overtemperature drive | Internal temp > 85°C | ERR LED: 3 blinks, DO2=1 | Improve cooling | | 1021 | 0x03FD | Overtemperature motor (via I²t) | Calculated motor temp > 130°C | ERR LED: 3 blinks | Reduce load | | 1030 | 0x0406 | Motor phase open load | Phase missing (unplugged or broken wire) | ERR LED: 4 blinks | Check connector | | 1031 | 0x0407 | Encoder / Hall error (if used) | Invalid hall pattern or missing encoder | ERR LED: 4 blinks | Replace encoder | | 1040 | 0x0410 | Position following error | Actual position lags target > limit | DO2=1 | Increase torque limit | | 1050 | 0x041A | Limit switch overtravel | Hardware limit reached | DO2=1, stops motion | Move opposite | | 1060 | 0x0424 | Illegal command | Invalid mode or parameter during run | DO2=1 | Reconfigure | | 1070 | 0x042E | EEPROM checksum error | Parameter memory corrupted | ERR LED: 5 blinks | Factory reset | | 1080 | 0x0438 | Internal ADC offset fault | Current measurement circuit failure | ERR LED: solid | Return for repair | | 1090 | 0x0442 | Watchdog timeout | Firmware task stalled | Fast blink | Cycle power | | 1100 | 0x044C | Brake control fault | Holding brake short or overload | DO3=1 | Check brake coil | 4.1 Overcurrent (Error 1000) and Short Circuit (1001) Symptoms: Motor stops abruptly, ERR LED single blink, DO3 activated. cmmo-st-c5-1-diop error codes
This allows a PLC to log and react to error progression. The DIOP version lacks object dictionary access for detailed error history. Therefore, operators must rely on blink codes and binary outputs. Festo recommends using the CMMO-ST-DIOP-IO-LINK adapter if more than 5 error types need differentiation. 8. Case Study: Intermittent Error 1031 (Encoder Error) System: CMMO-ST-C5-1-DIOP with external incremental encoder (TTL, 1024 PPR) for closed-loop stepper mode. This allows a PLC to log and react to error progression
Random error 1031 only when motor runs >500 rpm. crosstalk from motor phases.
DIOP systems without fieldbus are more vulnerable to EMI; proper shielding is mandatory. 9. Conclusion The CMMO-ST-C5-1-DIOP provides robust stepper motor control, but its error handling is inherently limited by the discrete I/O interface. Understanding the mapping of blink codes, digital output bits, and internal error numbers is essential for effective troubleshooting. This paper has cataloged all error codes, their physical origins, and recovery methods. For complex systems, engineers should consider adding an IO-Link master or upgrading to a fieldbus variant. However, with disciplined wiring, parameterization, and monitoring, the DIOP version remains a cost-effective and reliable solution. 10. Appendix: Quick Reference Card | ERR LED | Error | DO3 | Action | |---------|-------|-----|--------| | 1 blink | Overcurrent | 1 | Check motor/wiring | | 2 blinks | Voltage fault | 0/1 | Check supply | | 3 blinks | Temperature | 0 | Improve cooling | | 4 blinks | Motor connection | 0 | Reconnect motor | | 5 blinks | EEPROM | 0 | Factory reset | | Solid | Hardware | 1 | Replace unit |
Encoder cable not shielded, crosstalk from motor phases.