4. PARAMETERS FOR POSITIONING CONTROL
4
−
3
4.2.1
Setting the number of pulses per revolution / travel value per revolution / unit magnification
This section explains how to set the number of pulses per revolution, the travel
value per revolution, and the unit magnification.
(1) Setting method 1
(a) Finding the smallest position resolution (
∆
l).
The smallest position resolution (
∆
l) is determined by the travel value per
revolution (
∆
S) and the number of encoder feedback pulses (P
f
).
∆
S
∆
l =
P
f
(b) Finding the unit magnification (A
M
)
Find the unit magnification on the basis of
∆
l determined as described in (a)
above. However, make sure that the smallest command unit is not smaller
than
∆
l.
(For unit setting [mm] )
∆∆∆∆
l found in (a) [mm]
Smallest Command Unit [mm]
Unit Magnification (A
M
)
0.00001
<
∆
l
≤
0.0001
0.0001
1
0.0001
<
∆
l
≤
0.001
0.001
10
0.001
<
∆
l
≤
0.01
0.01
100
0.01
<
∆
l
≤
0.1
0.1
1000
[Example] Assuming that the travel value per revolution (
∆
S) is 10 [mm] and the
number of encoder feedback pulses (P
f
) is 8192 [PLS/rev]:
10 [mm]
∆
l =
8192 [PLS/rev]
= 0.00122
→
0.001
<
0.00122
≤
0.01
This means that the smallest command unit is 0.01 [mm] and the unit
magnification (A
M
) is 100.
Therefore, 0.01 [mm] units can be specified in commands.
(c) Finding the travel value per revolution (A
L
).
If the unit magnification (A
M
) is "1", the travel value per revolution is the
value of A
L
, unchanged. If the unit magnification (A
M
) is a value other than
"1", the travel value per revolution is the product of A
L
and A
M
.
[Example] Assume that the travel value per revolution is 10 [mm] and the unit
magnification is 10:
10000.0 [
µ
m]
A
L
=
100
= 100.0 [
µ
m]
Accordingly, 100.0 [
µ
m] is set as the travel value per revolution (A
L
) in this
case.
(d) Number of pulses per revolution (A
P
)
Set the number of feedback pulses per revolution of the encoder.
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