Omron R88M-K - Page 433

9-29
9 Details on Servo Parameter Objects
G5-series AC Servomotors and Servo Drives User’s Manual (with Built-in EtherCAT Communications)
9-4 Analog Control Objects
9
• Check the number of encoder pulses per motor rotation and number of external encoder pulses per
motor rotation, and set External Feedback Pulse Dividing Numerator (3324 hex) and External
Feedback Pulse Dividing Denominator (3325 hex).
• Set object 3324 hex to 0 to have the encoder resolution automatically set as the numerator.
• Refer to 6-6 Fully-closed Control on page 6-16.
Precautions for Correct UsePrecautions for Correct Use
• If this divider setting is wrong, there will be error between the position calculated from encoder
pulses and the position calculated from external encoder pulses. If the movement distance is
long, this error accumulates and causes a Excessive Hybrid Deviation Error (Error No. 25.0).
• The recommended divider setting is 1/40 ≤ External Feedback Pulse Ratio ≤ 160. If the ratio is
set too small, control to the unit of 1 external feedback pulse may be disabled. On the other
hand, if the external feedback pulse ratio is increased, operating noise may increase.
Additional Information
In the example below, ball screw pitch is 10 mm, encoder is 0.1 µm/pulse, and encoder
resolution is 20 bits (or 1,048,576 pulses)
• The direction of external encoder feedback count can be reversed.
• Refer to 6-6 Fully-closed Control on page 6-16.
Explanation of Set Values
3324 hex
External Feedback Pulse Dividing Numerator
Setting range 0 to 1048576 Unit − Default setting 0 Data attribute R
Size 4 bytes (INT32) Access RW PDO map Not possible.
3325 hex
External Feedback Pulse Dividing Denominator
Setting range 1 to 1048576 Unit − Default setting 10000 Data attribute R
Size 4 bytes (INT32) Access RW PDO map Not possible.
3326 hex
External Feedback Pulse Direction Switching
Setting range 0 to 1 Unit − Default setting 0 Data attribute R
Size 2 bytes (INT16) Access RW PDO map Not possible.
Set value Description
0 External encoder feedback pulse count direction not reversed
1 External encoder feedback pulse count direction reversed
csp (full)
pp (full)
hm (full)
csp (full)
pp (full)
hm (full)
=
Encoder resolution per motor rotation [pulses]
External encoder resolution per motor rotation [pulses]
3324 hex
3325 hex
=
Encoder resolution per motor rotation [pulses]
External encoder resolution per motor rotation [pulses]
3324 hex
3325 hex
100,000
1,048,576
=
csp (full)
pp (full)
hm (full)