HEIDENHAIN PWM 20 - Manual (Page 150)

November 2014 Checking incremental encoders 153
Sampling rate
It defines the interval for conversion of the incremental signals. The value is displayed in "kS/s"
(kilo samples per second), i.e.
Value
 1000 signal samples per second
Setting range for the sampling rate: 1 ... 2000 kS/s
If you select too low a scanning rate, the original signal cannot be displayed correctly (see
figures). Falsification of the signal display caused by undersampling is also referred to as aliasing
effect.
Number of samples
The number of samples defines, how many values are displayed on the screen.
Setting range: 2000 ... 100000 samples
Press the Plus or Minus key if you want to enter a new value.
When you restart the function, the value is reset to default.
Enter small values for high frequencies (i.e. high traversing speed or shaft speed).
Enter high values for low frequencies (i.e. low traversing speed or shaft speed).
High values can also be used for measuring over several signal periods (envelope curve,
e.g. in X-Y or Y-t display) in order to find signal drops.
Note
The higher the input frequency of the encoder (displayed under "Frequency" in the "Encoder
properties" field), the higher the sampling rate must be selected.
Recommendation: Sampling rate = 10
 max. input frequency
Falsified signal shape caused by too low a
sampling rate Suitable sampling rate
Note
When the function "Incremental signal" is restarted, the values for sampling rate and number
of samples are reset to the default settings 100 kS/s and 2000 samples.