6.3 Electronic Gear
121
3. Determine the reference unit to be used.
The reference unit is the minimum unit of the position data to move the load. (The minimum unit for ref-
erences from host controller.)
• Use the following units of measurement in physics.
Examples: 0.01 mm, 0.001 mm, 0.1
°
, 0.01 inch
4. Determine the load travel distance per load shaft revolution in reference units.
• When the ball screw pitch is 5 mm and the reference unit is 0.001 mm
5. Electronic gear ratio is given as (
).
If the deceleration ratio of the servomotor and load shaft is given as (
),
(where the load shaft rotates n times when the servomotor shaft rotates m times)
Make sure that the electronic gear ratio satisfies the following equation.
0.01
≤
Electronic gear ratio (
)
≤
100
The SERVOPACK will not operate properly if the electronic gear ratio is outside of this
range. Modify the load configuration or reference unit.
Ball Screw
Circular Table
Belt and Pulley
To move a table in 0.001 mm units
Reference unit: 0.001 mm
Determine the reference unit
according to machine specifications
and positioning accuracy.
Travel distance per load shaft revolution
(reference unit)
Travel distance by load shaft one revolution
Reference unit
=
= 5000 (reference unit)
5
0.001
Load shaft
P: Pitch
P
1 revolution =
P
Reference unit
Load shaft
1 revolution =
360
°
Reference unit
D: Pulley diameter
D
π
D
Load shaft
1 revolution =
π
D
Reference unit
B
A
m
n
Electronic gear ratio ( ) =
×
81
9
2
Travel distance per load shaft revolution (reference unit)
B
A
m
n
IMPORTANT
B
A
TOEP_C710806_03A_1_0.book Seite 121 Montag, 2. Juli 2007 3:55 15
