Troubleshooting

Startup issues

  • EtherCAT validation fails: verify slave order/ids, confirm process image matches hardware, and check for missing power/ESTOP on drives.
  • IOC won’t start after partial hardware failure: fix cabling/power first; restarting with missing slaves leaves the IOC unusable.

Motion issues

  • Axis won’t enable: ensure auto-enable is configured in axis.autoEnable (or motor record disabled), check STO and brake signals, and confirm SDOs downloaded for each drive channel.
  • Moves in wrong direction: prefer inverting at the slave via SDO; alternatives are encoder scaling sign or motor record DIR (last resort).
  • Homing stalls: confirm homing sequence type, switch polarity, and latch wiring; use homing monitoring/tolerances and check limit override logic.
  • Soft limits not respected: enable target/lag monitoring and confirm motor record soft limits are synced (if enabled).

PLC/scripting

  • Limit logic overrides: when using plcOverride for limits, write ax<id>.mon.lowlim/highlim in PLC code (1 = OK).
  • Command scripts: run through SCRIPTEXEC macros carefully; mismatched macros often break SDO verification.

Diagnostics

  • Use the hardware diagnostics guide for ec_diagnostic_messages.py usage and interpretation: Diagnostics.
  • Use read_el70xx_diag.sh or read_el5042_diag.sh for Beckhoff drives/encoders.
  • Check iocsh output for YAML lint/schema errors (v8+).

Error code quick map

ErrorTypical cause
ERROR_MON_BOTH_LIMIT_INTERLOCK24V feed for limits missing, cabling issue.
ERROR_MON_MAX_VELOCITY_EXCEEDEDVelocity too high, configuration mismatch, or encoder malfunction.
ERROR_MON_POS_LAG_INTERLOCKFollowing error, motion blocked, configuration mismatch (tolerance too tight).
ERROR_MON_STALLMotion stall.
ERROR_DRV_HW_ALARM_XHardware error, missing power supply; check dedicated hardware panels.
ERROR_ENC_NOT_READYEncoder issue, cabling issue, or missing power supply.
ERROR_EC_LINK_DOWNEtherCAT cabling issue, slave power missing.
ERROR_EC_STATUS_NOT_OKEtherCAT cabling issue, slave power missing.
ERROR_EC_MAIN_DOMAIN_DATA_FAILEDEtherCAT cabling issue, slave power missing.
ERROR_AXIS_SLAVED_AXIS_INTERLOCKSlaved axis in error (synchronized axes).