Siemens SIMATIC FM 351 Manual page 83

Example
An incremental encoder has the following data:
– Increments per encoder revolution: 5000
– Distance per encoder revolution: 1000 mm
– 1 increment = 4 pulses
This results in the following resolution (4x decoding):
Resolution
An SSI encoder has the following data:
– Increments per encoder revolution: 4096
– Distance per encoder revolution: 1000 mm
– 1 increment = 1 pulse
This results in the following resolution:
Resolution
Relationship Between Travel Range and Resolution
The travel range is limited by the numeric representation in the FM 351. The
number representation varies depending on the resolution. Therefore, make sure
that you are always within the permissible limits when specifying values.
The maximum travel range is represented in the table below:
Resolution (RES) is in the range
m
0.1 /
pulse
m
1 /
pulse
FM 351 Positioning Module
C79000-G7076-C351-02
1000 mm
= = 0.2000
5000 increments
mm
= 0.0500
pulse
1000 mm
= = 0.2441
4096 increments
m
RES < 1 /
pulse
m
RES 1000 /
pulse
Machine Data and Incremental Dimensions
mm
=
0.2000
increment
mm
= 0.2441
increment
Maximum travel range
8 8
–10 m to 10 m (–100 m to + +100 m)
9 9
–10 m to 10 m (–1000 m to +1000 m)
mm
4 pulses
mm
pulse
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