Sigma II User’s Manual
Chapter 5: Parameter Settings and Functions
5-28
5.2.5
Using the Electronic Gear Function
The electronic gear function enables the servomotor travel distance per input refer-
ence pulse to be set to any value. It allows the pulses generated by the host control-
ler to be used for control without having to consider the equipment gear ratio or the
number of encoder pulses.
n
Setting the Electronic Gear
Calculate the electronic gear ratio (B/A) using the following procedure, and set the
values in parameters Pn202 and 203.
1. Check equipment specifications related to the electronic gear:
•
Deceleration ratio
•
Ball screw pitch
•
Pulley diameter
2. Check the number of encoder pulses for the SGM
o
H servomotor.
Servomotor Model
and Encoder
Specifications
Encoder Type
Number of Encoder Pulses
Per Revolution (p/rev)
A
Incremental encoder
13–bit
2048
B
16–bit
16384
C
17–bit
32768
1
Absolute encoder
16–bit
16384
2
17–bit
32768
When the Electronic Gear
Function is Not Used
When the Electronic Gear
Function is Used
Ball screw pitch: 0.24in. (6mm)
Workpiece
No. of encoder pulses: 2048
No. of encoder pulses: 2048
Workpiece
Ball screw pitch: 0.24in. (6mm)
Reference unit: 1
µ
m
To move a workpiece 0.39in. (10mm):
1 revolution = 6mm. Therefore,
10 ÷ 6 = 1.6667 revolutions.
(2048
×
4) pulses = 1 revolution. So,
(1.6667
×
2048
×
4) = 13653 pulses
13563 pulses are input as the reference.
The equation must be calculated at the
host controller.
To move a workpiece 0.39in. (10mm):
Equipment conditions and reference
units must be defined for the electronic
gear function beforehand.
Reference unit is 1
µ
m. Therefore,
10mm
1
µ
m
=
10000 pulses
Ball screw pitch
Deceleration ratio
