Siemens SINUMERIK 840Di Function Manual page 90

Detailed Description
2.2 Encoder monitoring
2.2.2 Zero mark monitoring
Function
The zero mark monitoring monitors the number of encoder impulses between two encoder
zero marks of the active measuring system. In a properly functioning measuring system, the
number of encoder impulses detected from encoder zero mark to encoder zero mark must
remain the same.
MD36310 $MA_ENC_ZERO_MONITORING (Zero mark monitoring)
Note
The zero mark monitoring is only active below the assigned encoder limit frequency for new
synchronization:
MD36302 $MA_ENC_FREQ_LIMIT_LOW
2-18
Axis Monitoring, Protection Zones (A3)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0