5.14 Setting Unit Systems
5.14.1 Setting the Position Reference Unit
5-46
Electronic Gear Ratio Setting Examples
Setting examples are provided in this section.
•
Rotary Servomotors
*
For a Rotary Servomotor with an encoder resolution of 24 bits (16,777,216), Pn20E (Electronic Gear Ratio
(Numerator)) is automatically set to 16 and Pn210 (Electronic Gear Ratio (Denominator)) is automatically set to 1.
Therefore, the encoder resolution will be equivalent to 20 bits (1,048,576). Consider this when you set the position
reference unit in
position user unit
(2701 hex).
•
Linear Servomotors
A setting example for a Serial Converter Unit resolution of 256 is given below.
*
For a Linear Servomotor, both Pn20E (Electronic Gear Ratio (Numerator)) and Pn210 (Electronic Gear Ratio
(Denominator)) are automatically set to 1. Consider this when you set the position reference unit in p
osition user
unit
(2701 hex).
Step
Description
Machine Configuration
Ball Screw
Rotary Table
Belt and Pulley
1
Machine
Specifications
•
Ball screw lead: 6 mm
•
Gear ratio: 1/1
•
Rotation angle per revo-
lution: 360
°
•
Gear ratio: 1/100
•
Pulley dia.: 100 mm
(Pulley circumference:
314 mm)
•
Gear ratio: 1/50
2
Encoder Resolution
16,777,216 (24 bits)
16,777,216 (24 bits)
16,777,216 (24 bits)
3
Reference Unit
0.001 mm (1
μ
m)
0.01
°
0.005 mm (5
μ
m)
4
Travel Distance per
Load Shaft Revolution
(Reference Units)
6 mm/0.001 mm =
6,000
360
°
/0.01
°
= 36,000
314 mm/0.005 mm =
62,800
5
Electronic Gear Ratio
*
6
Position User Unit
(2701 hex)
Numerator: 1,048,576
Numerator:
104,857,600
Numerator: 52,428,800
Denominator: 6,000
Denominator: 36,000
Denominator: 62,800
Step
Description
Machine Configuration
1
Linear Encoder Pitch
0.02 mm (20
μ
m)
2
Reference Unit
0.001 mm (1
μ
m)
3
Electronic Gear Ratio
*
4
Position User Unit
(2701 hex)
Numerator: 256
Denominator: 20
Reference unit: 0.001 mm
Load shaft
Encoder:
24 bits
Ball screw lead:
6 mm
Reference unit: 0.01°
Load shaft
Encoder: 24 bits
Gear ratio:
1/100
Reference unit: 0.005 mm
Load shaft
Gear ratio:
1/50
Pulley dia.:
100 mm
Encoder: 24 bits
16,777,216
6,000
1
16
=
×
B
A
1
1
×
100
1
16,777,216
36,000
1
16
=
×
B
A
×
50
1
16,777,216
36,000
1
16
=
×
B
A
×
Reference unit:
0.02 mm (20
m)
Forward direction
A
20 (
μ
m)
B
1 (
μ
m)
=
×
1
1