Sinumerik Alarm 20001 Channel %1 axis %2 no cam signal present

Sinumerik Alarm 20001 Channel %1 axis %2 no cam signal present

%1 = Channel number
%2 = Axis name, spindle number

At the beginning of phase 2 of reference point approach, the signal from the reduction cam is no longer available. Phase 2 of reference point approach begins when the axis remains stationary after deceleration to the reduction cam. The axis then starts in the opposite direction in order to select the next zero marker of the measuring system on leaving the reduction cam or approaching it again (negative/positive edge).

– NC Stop on alarm.
– NC Start disable in this channel.
– Alarm display.
– Interface signals are set.
– If the axis is a single axis when this alarm is triggered, the alarm is only effective for this axis (not effective for e.g. the channel or mode group)

Please inform the authorized personnel/service department. Check whether the deceleration path after the approach velocity is greater than the distance to reference point cam – in which case the axis cannot stop until it is beyond the cam. Use longer cam or reduce the approach velocity in machine data 34020 REFP_VELO_SEARCH_CAM. When the axis has stopped at the cam, it must be checked whether the signal “DECEL- ERATION REFERENCE POINT APPROACH” is still available at the interface to the NCK (DB 31 – 48, DBX 12.7). • Hardware: Wire break? Short circuit? • Software: User program?

Program Continuation:
Clear alarm with the RESET key. Restart part program


  1. Siemens Diagnostics Guide by Siemens
Sinumerik Alarm 20001 Channel %1 axis %2 no cam signal present