HEIDENHAIN PWM 20 - Manual (Page 198)

November 2014 Checking incremental encoders 201
The image shows the inverted TTL output signals (after was pressed)
and the fault-detection signal.
Display field 4 - Ua1
Display field 5 - Ua2
Display field 6 - Ua0
Display field 7 - UaS
Note
Select the sampling rate according to the input frequency (min. 2000 samples,
max. 100000 samples). When you close and restart the Level function, the number of
samples is reset to the minimum value 2000.