Lenze E94AxPExxxx - Manual (Page 307)

Lenze · 9400 Servo PLC· Reference manual · DMS 4.0 EN · 11/2013 · TD05/06
307
7 Encoder evaluation
7.3 Parameter setting
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7.3.12 Encoder angular drift monitoring
The optional encoder angular drift monitoring monitors a potential deviation between the actual
encoder angle and the angle calculated by the counting of increments in the encoder evaluation.

The encoder angular drift monitoring is activated by parameterising an error response that
is not "0: No response" in C00621 .
If a deviation higher than 45° (electrical) is recognised when monitoring is activated:
• The error message "Encoder monitoring: pulse deviation detected" is entered in the logbook of
the controller.
• The error response parameterised in C00621 is triggered.
• The "Reference known" status of the "Homing" basic drive function is reset (if this status was set
before)

Tip!
A deviation may occur, for instance, by incorrect parameter setting of the encoder
increments, by lines in the form of interferences caused by EMC or loss of lines caused by
EMC.
The encoder angular drift monitoring for encoders with and without absolute information is
implemented by two different principles which are explained in detail in the following subchapters.
7.3.12.1 Angular drift monitoring for encoders without absolute information
When an encoder without absolute information is used, the number of increments between two
zero pulses (one revolution) is monitored. This value must equal the encoder increments set in
C00420 .

Note!
After mains switching, monitoring is only active after second incoming zero pulse since
the first line difference to be used can only be calculated with the second and first zero
pulse.
When the motor (and thus the encoder) is replaced, it is very likely that a angular drift
error occurs within the first revolution after acknowledging the encoder error since the
monitoring function cannot recognise that the encoder has been replaced.