Siemens S7-300 - Page 92

Machine and cam data
9.11 Resolution
FM 352 electronic cam controller
92 Operating Instructions, 05/2011, A5E01071724-03
Example
● An incremental encoder has the following data:
– Increments per encoder revolution: 5000
– Distance per encoder revolution: 1000 mm
– 1 increment = 4 pulses
Resultant resolution (quadruple evaluation):
Resolution
= 1000 mm / 5000 increments
= 0.2000
mm
/
increment
= 0.2000
mm
/
4 pulses
= 0.0500
mm
/
pulse
● An SSI encoder has the following data:
– Increments per encoder revolution: 4096
– Distance per encoder revolution: 1000 mm
– 1 increment = 1 pulse
Resultant resolution:
Resolution
= 1000 mm / 4096 increments
= 0.2441
mm
/
increment
= 0.2441
mm
/
pulse
Dependency between the traversing range and the resolution
The traversing range is limited by the numeric representation in FM 352. The number
representation varies, depending on the resolution. You should thus make sure that your
specifications are always within the permitted limits.
The table below shows the maximum traversing range:
Resolution (RES) is in the range Maximum traversing range
0.1
µm
/
pulse
≦ RES < 1
µm
/
pulse
-10
8
µm to 10
8
µm (-100 m to + 100 m)
1
µm
/
pulse
≦RES ≦ 1000
µm
/
pulse
-10
9
µm to 10
9
µm (-1000 m to + 1000 m)