YASKAWA SGDB-15VN User Manual page 85

Application
5.2.1 Electronic Gear Function
5.2 Position Control
5.2.1 Electronic Gear Function
■ Setting the Electronic Gear Ratio (B/A)
Load travel distance per load shaft revolution r e v o l u t i o n (in distance units)
(in reference units)
Load Travel Distance
per Load Shaft
P
360°
rcD
The electronic gear function enables the distance the motor travels for one reference unit to be
set to any value. More specifically, the value is set based on the number of encoder pulses, refer-
ence unit (minimum unit Qf position data for moving the load), and machine gear ratio. When
the electronic gear ratio is 1/1, the motor will move one reference unit per pulse input.
Determining the Reference Unit
The electronic gear ratio represents the number of encoder pulses per reference unit.
The reference unit is the minimum unit of position data for moving the load, e.g., 0.01 mm, 0.1°,
or 0.01 inches.
Example: Reference Unit = 0.1 pm
If a move reference of 50000 reference units is input, the load moves 5 mm
(50000 x 0.1 = 5000 p.m = 5 mm).
Determine the reference unit based on factors like equipment specifications and positioning pre-
cision.
Determining the Load Travel Distance per Load Shaft Revolution
in Reference Units
Table 5.1 shows an example of the load travel distance per load shaft revolution.
Table 5.1 E x a m p l e of the Load Travel Distance per Load Shaft Revolution
Revolution
Ball screw
Disc table
Belt and pulley
Example: Load Travel Distance per Load Shaft Revolution= 12 mm (0.47 in), Reference Unit
= 0.01 mm (0.0004 in)
Load travel distance per load shaft
Example of the Load Structure
1 revolution
: e 1 revolution
1 revolutionz(4-) D
5 -4
Reference unit
P
P: Pitch
360°
7rD
( + )