Siemens SINUMERIK codes
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Siemens SINUMERIK Controller

Program/G-code · Intermediate · 30-120 minutes

Alarm 20002

Siemens 20002 - Axis zero mark not found

The hardware zero mark of the incremental position encoder or the substitute zero mark of the absolute position encoder is not within a defined section. Phase 2 of the reference point approach ends when the zero mark of the encoder has been detected after the rising/ falling edge of the NC/PLC interface signal DB31,. DBX12.7 (Deceleration reference point approach) has given the trigger start. The maximum distance between the trigger start and the zero mark that follows is defined in the MD34060 $MA_REFP_MAX_MARKER_DIST. The monitor prevents a zero mark signal from being overtraveled and the next being evaluated as reference point signal. (Faulty cam adjustment or excessive delay by the PLC user program) Control reaction: NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm.

Siemens SINUMERIKProgram/G-codeIntermediate30-120 minutes

20002

Siemens 20002 - Axis zero mark not found

Axis zero mark not found

The hardware zero mark of the incremental position encoder or the substitute zero mark of the absolute position encoder is not within a defined section. Phase 2 of the reference point approach ends when the zero mark of the encoder has been detected after the rising/ falling edge of the NC/PLC interface signal DB31,. DBX12.7 (Deceleration reference point approach) has given the trigger start. The maximum distance between the trigger start and the zero mark that follows is defined in the MD34060 $MA_REFP_MAX_MARKER_DIST. The monitor prevents a zero mark signal from being overtraveled and the next being evaluated as reference point signal. (Faulty cam adjustment or excessive delay by the PLC user program) Control reaction: NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm.

Safety

  • Only qualified personnel should diagnose and clear control alarms; follow the machine builder's safety procedures and lockout/tagout where hardware work is required.

Common Causes

  • The hardware zero mark of the incremental position encoder or the substitute zero mark of the absolute position encoder is not within a defined section.
  • Phase 2 of the reference point approach ends when the zero mark of the encoder has been detected after the rising/ falling edge of the NC/PLC interface signal DB31, ... DBX12.7 (Deceleration reference point approach) has given the trigger start.
  • The maximum distance between the trigger start and the zero mark that follows is defined in the MD34060 $MA_REFP_MAX_MARKER_DIST.

Troubleshooting Steps

  1. 1Please inform the authorized personnel/service department.
  2. 2Check the cam adjustment and make sure that the distance is sufficient between the end of the cam and the zero marker signal that follows.
  3. 3The path must be greater than the axis can cover in the PLC cycle time.
  4. 4Increase the MD34060 $MA_REFP_MAX_MARKER_DIST, but do not select a value greater than the distance between the 2 zero markers.
  5. 5This might result in the monitor being switched off.
  6. 6Clear alarm with the RESET key. Restart part program

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