Siemens SIMATIC FM 351 Installation Manual page 89

System of Units in
In this chapter we use the mm system of units when stating the minimum
this Chapter and maximum values. For determining the limits in the other systems of
units, apply the following calculation:
mm
mm
Relationship be-
The encoder signals from a connected encoder are evaluated by the FM 351
tween Increments and converted to the momentary system of units. For the conversion, the fol-
and System of
lowing resolution (see Chapter 8.6) is used:
Units
If the FM 351
this means that the axis was moved by a distance of 1 mm.
Speeds
The speed is displayed in the set system of units.
Travel Range of The FM 351 can only process a certain number range. This number range
Incremental
determines the travel range. The travel range is dependent on the resolution
Encoders and is:
Note
For the rotary axis the following applies: The reproducibility of the reference
point is only ensured if an integer ratio exists between the incremental val-
ues for the value End of rotary axis and the value Displacement per en-
coder revolution.
Travel Range of With an absolute encoder the travel range is determined by the total number
Absolute Encoders
of encoder steps. In addition please note:
FM 351 Positioning Function Module
EWA 4NEB 720 6001-02
For the Conversion of
inches
degrees
has counted 10 increments and
a resolution of 100 m per increment is set by the parameterized encoder
data,
from –100 m to +100 m for a resolution < 1
from –1000 m to +1000 m for a resolution
With a linear axis the absolute encoder must at least cover the working
range.
With a rotary axis the absolute encoder must exactly cover the rotary axis
range.
Machine Data and Increments
Calculate
–1
Value (inch) = Value(mm) 10
Value (degrees) = Value (mm) 10
m
/
increment
m
1 /
increment
–1
8
8-3