Lika SFA-10000-FD, User Manual

Page: 42 / 88

SFA-5000 • SFA-10000 DeviceNet
EXAMPLE
We install the following draw-wire encoder:
SFA-5000-FD-8192-M12
.
The physical values are:
Stroke per turn of the drum = 200 mm (7.874”)
Physical resolution per turn = 13 bits = 8,192 cpr
Max. number of physical revolutions = 4,096 revolutions
Total physical resolution = 25 bits = 33 554 432 information
Physical linear resolution = 0.024 mm = 24 µm
Max. number of turns of the drum = 25
Max. measuring length = 5,000 mm (196.85”)
Number of information = 204,800
Let's suppose that we need a tenth of a millimetre linear resolution in the
specific installation.
•
Enable the scaling function:
4 Scaling function control
attribute = 1
•
Custom resolution per turn =
5 Measuring units/rev
= 2,000 cpr
•
Linear resolution = 0.1 mm = 100 µm
Linear resolution =
Stroke per turn
=
200
= 0.1 mm
5 Measuring units/rev
2,000
The custom number of revolutions can be as the physical number of revolutions:
Custom number of encoder revolutions =
6 Total measuring range
= 4,096
5 Measuring units/rev
•
6 Total measuring range
= 8 192 000
NOTE
Please note that if you set a preset along the path, when the encoder moves
back and cross the zero, the value immediately after 0 will be 8 192 000 - 1, i.e.
8 191 999.
... 8,191,997 8,191,998 8,191,999 0 1 2 ...
EXAMPLE
Using the values in the previous example let's suppose that the travel in the
application is 2 m long. As the stroke per turn is 200 mm you need 10
revolutions to cover the travel length.
•
6 Total measuring range = 5 Measuring units/rev * custom number
of revolutions = 2,000 * 10 = 20,000
In fact:
Custom number of encoder revolutions =
6 Total measuring range
= 10
5 Measuring units/rev
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