12.8 Counter Function Module
12.8.2 Electronic Gear
12
Function
s
of the Contr
oller
S
ection
12-59
Electronic Gear Settings
Use the following procedure to set the electronic gear.
1.
Check the following machine specifications.
2.
Set fixed parameter No. 14 (Number of Pulses Per Encoder Rotation) to the amount of
change in the current count when the encoder rotates one revolution.
3.
Set the reference unit (the minimum unit of reference data used to move the load) by
setting fixed parameter No. 8 (Reference Unit Selection) and fixed parameter No. 9
(Number of Digits Below Decimal Point). Consider factors such as the machine specifi-
cations and positioning accuracy when you determine the reference unit.
4.
Use the reference unit to determine the travel distance per machine rotation, and then
set fixed parameter No. 10 (Travel Distance per Machine Rotation) to that travel dis-
tance.
Electronic Gear-related
Elements
•
Gear ratio
•
Ball screw pitch
•
Pulley diameter, etc.
If the reference unit is 1 μm, and 50,000 reference pulses are input, the workpiece will
move 50,000 × 1
μ
m, or 50 mm.
Travel distance per load shaft revolution (reference units) =
Distance moved per rotation of the load shaft
Reference units
Examples of machine configurations and the formulas used for them are given in the fol-
lowing table.
The following formula is used to calculate the travel distance (reference units) per load
shaft rotation when the ball screw pitch is 5 mm and the reference unit is 0.001 mm.
Gear ratio
Ball
s
crew pitch
Moving the Table with a Reference Unit of 0.001 mm.
Reference unit: 0.001 mm
Example
Example
Ball Screw
Rotary Table
Belt and Pulley
Example machine
configuration
Formula for calculat-
ing the travel dis-
tance (reference
units) per load shaft
P
P: Pitch
Load
s
haft
Load
s
haft
D
p
D
D: Pulley diameter
Load
s
haft
P
Reference unit
3
60°
Reference unit
π
D
Reference unit
Example
5
= 5,000 (reference units)
0.001
