HEIDENHAIN PWM 20 - Manual (Page 166)

November 2014 Checking incremental encoders 169
Explanation of the "Sampling rate" and "Number of periods" bar
Sampling rate [kS/s]
For the description of the sampling rate also refer to the descriptions of "Sampling rate" and
"Number of samples".
Setting range: 1 ... 2000 [kS/s]
Minimum sampling rate = Signal frequency x 20
Example:
Signal frequency 10 kHz = Minimum value for the sampling rate is 200
Number of periods
Selectable between 1000 and 10,000,000
Attention: Large amount of data
File size [bytes] = Sampling rate x Number of periods x 12
Example:
Sampling rate = 1000; Number of periods = 100,000, File size = 1.2 GB
Calculating the number of periods
The measuring range of the encoder is determined by entering the number of periods.
For rotary and angle encoders the line count of the encoder (e.g. 2048 lines; indicated on the
ID label) must be entered. This corresponds to one revolution (= total measuring range = 360°).
For linear encoders, the following formula can be used to calculate the number of periods from
the measuring length:
Example:
LS 487 linear encoder; measuring length ML = 320 mm; signal period 20 µm
The calculated number of periods is used to check the entire measuring length. If you want to
check the measuring range several times or to check only parts of it, larger or smaller values can
be entered.
Note
The signal frequency can be determined with the function "Analog; Encoder properties;
Freq".
Note
Processing these large amounts of data may take quite long, depending on the processing
power.
Note
Refer to the sales literature for the value to be used for the signal period.