Yaskawa SGDS Sigma III Servo Amplifier - Manual (Page 204)

7.4 Settings According to Host Controller
7-15
(1) Setting the Electronic Gear
Calculate the electronic gear ratio (B/A) using the following procedure, and set the values in parameters Pn20E
and 210.
1. Check machine specifications.
Items related to the electronic gear:
• Deceleration ratio
• Ball screw pitch
• Pulley diameter
2. Check the number of encoder pulses for the servomotor.
3. 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.)
• Use the following unit of measurement in physics.
0.01 mm (0.0004 in), 0.001 mm (0.00004 in), 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 (0.20 in) and the reference unit is 0.001 mm (0.00004 in)
Encoder Type Number of Encoder Pulses
Per Revolution (P/R)
Incremental encoder 13 bits 2048
16 bits 16384
17 bits 32768
20 bits 262144
Absolute encoder 16 bits 16384
17 bits 32768
20 bits (without
multi-turn data) 262144
Ball screw pitch
Deceleration ratio
Reference unit: 0.001mm
Determine the reference unit according to
equipment specifications and positioning accuracy.
.
To move a table in 0.001mm units
EXAMPLE
Travel distance per load shaft revolution (reference unit) =
Travel distance per load shaft revolution
Reference unit
EXAMPLE