Siemens SINUMERIK 840D sl Commissioning Manual page 156

NCK start-up
10.5 Parameterize axis data
Remedy
After the axes have come to a stop, the position control is resumed after the alarm (RESET
at the machine control panel) is acknowledged.
NOTICE
The axis affected must be re-referenced.
Encoder zero mark monitoring
The zero mark monitoring of the encoder of a machine axis checks whether pulses were lost
between two zero mark passes.
● MD36310 ENC_ZERO_MONITORING (zero mark monitoring)
is used to enter the number of detected zero mark errors at which the monitoring is to
respond.
Special situation:
A value of 100 will additionally disable hardware monitoring of the encoder.
Error response
● Alarm: "25020 Zero mark monitoring"
and stopping the machine axes using a speed setpoint ramp whose characteristic is set in
● MD36610 AX_EMERGENCY_STOP_TIME (time for braking ramp when an error occurs)
Error causes
● MD36300 ENC_FREQ_LIMIT [n] (encoder limit frequency) set too high.
● Encoder cable damaged.
● Encoder or encoder electronics defective.
Position tolerance when switching over the encoder
It is possible to switch between the two encoders or position measuring systems of a
machine axis at any time. The permissible position difference between the two position
measuring systems when switching over is monitored.
● MD36500 ENC_CHANGE_TOL (max. tolerance on actual position value switchover)
Error response
● Alarm: "25100 Measuring system cannot be switched over"
The requested switchover to another encoder is not carried out.
Error causes
● The specified permissible tolerance is too small.
● The position measuring system to which you want to switch over to is not referenced.
156
Commissioning Manual, 07/2007, 6FC5397-2AP10-3BA0
IBN CNC: NCK, PLC, drive