Yaskawa Sigma II Series Servo System - Manual (Page 114)

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
reference pulse to be set to any value. It allows the pulses generated by the host
controller to be used for control without having to consider the equipment gear ratio
or the number of encoder pulses.
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 H servomotor.
Note: The number of bits representing the resolution of the applicable encoder is not the same as the
Servomotor Model
and Encoder
Specifications
Encoder Type
Number of Encoder Pulses
Per Revolution (PPR)
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 μm
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 μm. Therefore,
10mm
1 μm
= 10000 pulses
Ball screw pitch
Deceleration ratio
Gear Ratio