Siemens SIMATIC FM 351 - Resolution

Machine Data and Incremental Dimensions
8-22
FM 351 Positioning Module
C79000-G7076-C351-02
8.7 Resolution
Definition
The resolution specifies the distance corresponding to one pulse. It is a measure
of the accuracy of the positioning and also determines the maximum possible
travel range of the FM 351.
The resolution (RES) is calculated as illustrated in the following table:
Incremental Encoders Absolute Encoders
Input
values
• Displacement per encoder rev.
• Increments per encoder
revolution:
– Pulse evaluation: 4x
– 1 increment = 4 pulses
• Displacement per encoder rev.
• Increments per encoder
revolution:
– 1 increment = 1 pulse
Calculatio
n
RES 
dist
encoder rev
pulses
encoder rev
Note
All position information is rounded up to the integral multiple of the resolution. This
allows you to distinguish between the entered and the used values.
Range of Values of the Resolution
The selected system of units decides the range of values for the resolution:
System of
Units
Specified in... Range for the Resolution
mm 10
–3
mm 0.110
–3
.... 100010
–3
mm/pulse
inches 10
–4
inches 0.110
–4
.... 100010
–4
inches/pulse
degrees 10
–4
degrees
10
–3
degrees
10
–2
degrees
0.110
–4
.... 100010
–4
degrees/pulse
0.110
–3
.... 100010
–3
degrees/pulse
0.110
–2
.... 100010
–2
degrees/pulse