YASKAWA SGDH User Manual page 484

8 Operation
8.6.2 Setting the Electronic Gear
(5) Electronic Gear Ratio Setting Examples
The following examples show electronic gear ratio settings for different load configurations.
Step Operation
1
Check machine
specifications.
2
Check the number
of encoder pulses.
3
Determine the ref-
erence unit used.
4
Calculate the travel
distance per load
shaft revolution.
5
Calculate the elec-
tronic gear ratio.
6
Set parameters.
Reduce the fraction (both numerator and denominator) since the calculated result will not be within the setting
range. For example, reduce the numerator and denominator by four to obtain Pn201=32768, Pn203=3925 and
complete the settings.
(6) Electronic Gear Ratio Equation
Reference pulse
B
A
∆ (mm/P)
∆ (mm/P): Reference unit
(P/R): Encoder pulses
P
G
P (mm/rev): Ball screw pitch
m
: Deceleration ratio
n
n × P
B
( )
× = 4 × P × m
∆
A
4 × P × m ×
B
( ) =
A
Ball Screw
Reference unit: 0.001 mm
Load shaft
13-bit encoder Ball screw
pitch: 6 mm
Ball screw pitch: 6 mm
Deceleration ratio: 1/1
13-bit: 2048 P/R
1 Reference unit: 0.001 mm
(1 µm)
6 mm/0.001 mm=6000
2048 × 4
B 1
= ×
A 6000 1
Pn202 8192
Pn203 6000
Servomotor
+
Speed
Position
loop
loop
-
×4
(P/rev)
P
G
G
∆ 4 × P
m
G G
×
=
n × P
n
P
×
∆
Load Configuration
Disc Table
Reference unit: 0.1°
Deceleration
ratio:
3 : 1
Load shaft
13-bit encoder
Rotation angle per revolution:
°
360
Deceleration ratio: 3/1
13-bit: 2048 P/R
°
1 Reference unit: 0.01
° °
360 /0.1 =3600
2048 × 4
B 3
×
=
A 3600 1
Pn202 24576
Pn203 3600
n
Pitch = P (mm/rev)
m
Set A and B with the following parameters.
Pn202 Pn203
A B
8-52
Belt and Pulley
Reference Unit: 0.02 mm
Load shaft
Deceleration
ratio
Pully diameter:
2 : 1
100 mm
16-bit encoder
Pulley diameter: 100 mm
(pulley circumference: 314 mm)
Deceleration ratio: 2/1
16-bit: 16384 P/R
1 Reference unit: 0.02 mm (20 µm)
314 mm/0.02 mm=15700
16384 × 4
B 2
= ×
1
A 15700
Pn202 ∗
131072
Pn203 15700