YASKAWA SGMJV User Manual page 148

(3) Electronic Gear Ratio Equation
Refer to the following equation to determine the electric gear ratio.
Reference pulse
B
A
mm/P
mm/P Reference unit
P P/rev Encoder resolution
G
P mm/rev Ball screw pitch
n
: Gear ratio (m is the rotation of the motor and n is the rotation of the load shaft.)
m
n × P
B
×
= P
( )
A
B
( ) =
A
(4) Electronic Gear Ratio Setting Examples
The following examples show electronic gear ratio settings for different load configurations.
Step Operation
Check machine specifica-
1
tions.
Check the encoder reso-
2
lution.
Determine the reference
3
unit used.
Calculate the travel dis-
4 tance per load shaft revo-
lution.
Calculate the electronic
5
gear ratio.
6
Set parameters.
Servomotor
+
Speed
Position
loop
loop
−
P P/rev
G
× m
G
P × m × P m
G G
×
=
n
n × P
P
Ball Screw
Reference unit: 0.001 mm
Load shaft
20-bit encoder Ball screw
pitch: 6 mm
Ball screw pitch: 6 mm
Gear ratio: 1/1
1048576 (20-bit)
Reference unit: 0.001 mm
(1 μm)
6 mm/0.001 mm=6000
B 1048576
=
A 6000
Pn20E: 1048576
Pn210: 6000
5.4 Operating Using Position Control with Pulse Train Reference
n
Pitch = P (mm/rev)
m
Set A and B with the following parameters.
A Pn210 B Pn20E
Load Configuration
Disc Table
Reference unit: 0.01°
Gear ratio:
1/100
Load shaft
20-bit encoder
Rotation angle per revolu-
tion: 360°
Gear ratio: 1/100
1048576 (20-bit)
Reference unit: 0.01°
360°/0.01°=36000
1 B 1048576 100
=
1 A 36000 1
Pn20E: 104857600
Pn210: 36000
Belt and Pulley
Reference unit: 0.005 mm
Load shaft
Gear ratio
1/50
Pulley diameter:
100 mm
20-bit encoder
Pulley diameter: 100 mm
(pulley circumference: 314
mm)
• Gear ratio: 1/50
1048576 (20-bit)
Reference unit: 0.005 mm
(5 μm)
314 mm/0.005 mm=62800
B 1048576 50
=
A 62800 1
Pn20E: 52428800
Pn210: 62800
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