Omron XTRADRIVE User Manual page 94

XtraDrive User Manual
2. Determine the reference unit used.
A reference unit is the minimum position data unit used to move a
load (minimum unit of reference from the host controller).
To move a table in 0.001 mm units
Examples (in mm):
• Reference unit can be 0.1in or 0.01in or 0.01mm or 0.001mm,
• When the reference unit is 1µm
3. Determine the travel distance per load shaft revolution in reference
units.
Travel distance per load shaft revolution =
• When the ball screw pitch is 0.20in (5mm) and the reference unit
Ball Screw
4. Electronic gear ratio is given as:
If the gear ratio of the motor and the load shaft is given as:
m is the rotation of the motor and n is the rotation of the load shaft,
Electronic gear ratio
Note: Make sure the electronic gear ratio satisfies the following condition:
0.01 ≤ Electronic gear ratio
The servo amplifier will not work properly if the electronic gear ratio exceeds this range. In that case,
modify either the load configuration or the reference unit.
Reference unit: 0.001 mm
Determine the reference unit according to
equipment specifications and positioning accuracy.
etc. A reference unit of one pulse moves the load by one
reference unit.
If a reference of 50000 units is input, the load moves 50mm
(1.97in) (50000 ⋅ 0.001mm = 50mm).
is 0.00004in (0.001mm),
. 0 20
= 5000 (reference units)
. 0 00004
Disc Table
 
B
 
=
  Travel
A
 
B
 
≤ 100
 
A
5-26
Chapter 5: Parameter Settings and Functions
Travel distance per
Reference
 
B
 
 
A
Number of encoder pulses
distance per load shaft revolution
load shaft revolution
Unit
Belt and Pulley
π
π
m
where
n
x 4
m
x
(reference unit)
n