Sinumerik Alarm 25021 Axis %1 zero mark monitoring of passive encoder
%1 = Axis name, spindle number
Monitoring relates to the encoder that is not used by the position control! (Interface signal DB 31 – 48, DBX 1.5 = 0 or 1.6 = 0) The position encoder pulses between 2 zero marker pulses are counted (hardware function). A check is made in the interpolation cycle grid (standard setting 4 ms) as to whether the encoder always issues the same number of pulses between the zero markers. As soon as a difference is registered in the 4 counter bits of lowest significance, an alarm is triggered!
– Alarm display.
Please inform the authorized personnel/service department. The differences can result from transmission errors, disturbances, encoder hardware faults or from the evaluation electronics in the encoder used for position control. The actual value branch must there- fore be checked: 1. Transmission path: Check the actual-value connector on the motor and on the FDD module for correct contacting, encoder cable for continuity, and also check for short-circuits or grounding (loose contact?). 2. Encoder pulses: Encoder power supply within the tolerance limits? 3. Evaluation electronics: Replace or reconfigure the drive module used. Monitoring can be switched off by setting machine data ENC_ZERO_MON_ACTIVE [n]=… N … encoder number: 1, 2) to 0.
Clear alarm with the Delete key or NC START.
- Siemens Diagnostics Guide by Siemens