Yaskawa DR2 Sigma Servo - Manual (Page 95)

APPLICATIONS OF Σ-SERIES PRODUCTS
3.2.5 Using Electronic Gear
82
3.2.5 Using Electronic Gear
For position control only.
1) Outline
The electronic gear function enables the motor travel distance per input reference pulse
to be set to any value. It allows the host controller to perform control without having to
consider the machine gear ratio and the number of encoder pulses.
When Electronic Gear Function
is Not Used
When Electronic Gear Func-
tion is Used
Workpiece
Number of
encoder
pulses: 2048
Ball screw
pitch: 6 mm
Reference
unit: 1 μm
To move a workpiece 10 mm,
One revolution is equivalent to 6 mm, so
10
6 = 1.6666 (revolutions)
2048 x 4 (pulses) is equivalent to one revolution, so
1.6666 x 2048 x 4 = 13653 (pulses)
A total of 13653 pulses must be input as a reference.
the host controller needs to make this calculation.
Machine conditions and reference unit
must be defined for the electronic gear
function beforehand.
To move a workpiece 10 mm:
Reference unit is 1 μm, so
10 mm
1 μm = 10000 pulses
Number of
encoder
pulses: 2048
Ball screw
pitch: 6 mm
Workpiece
2) Setting the Electronic Gear
Calculate the electronic gear ratio (B/A) according to the procedure below and set the
value in Cn-24 and Cn-25.
a) Check the machine specifications.
Items related to electronic gear:
− Gear ratio
− Ball screw pitch
− Pulley diameter
b) Check the number of encoder pulses for the SGM Servomotor.
Motor Type Encoder Type Number of Encoder
Pulses Per Revolution
SGM-jjj31j
SGMP-jjj31j
Incremental encoder 2048
SGM-jjjW1j
SGMP-jjjW1j
Absolute encoder 1024
Same as user constant Cn-11 settings.
3
Positions
Gear ratio
Ball screw pitch