5 Operation
98 SD780 Series Servo Technical Manual
(Note) 1. When the mantissa appears, please round the number after the decimal point.
2. When the pitch value of the external encoder grating ruler with motor rotation for 1 turn is
not an integer, relative to the position loop gain (KP), feedforward, position command speed,
monitoring as the state of containing error. But it has nothing to do with the position loop, so it will
not affect the position accuracy.
Related parameter
Function
code
Parameter
Range
Default
Unit
Communication
address
When
enabled
Pn253
Resolution of
external
grating ruler
4
～
1048576
32768
Pulse/r
0x0253
After
Restart
Set the pitch value (feedback pulse number) of external grating ruler when the motor shaft rotates
for 1 turn
5.8.6 Setting of frequency division pulse output signal of grating ruler /
encoder
Set the frequency division output of external position to pn070. The set value should input A, B
phase edge values.
Pitch of grating ruler of external encoder: 16mm.
Ball screw lead: 16mm.
Speed: 160mm/s.
The setting value is “4000” when the output is 1 μm with 1 pulse (4 times of increasing value).
The setting value is “8000” when the output is 0.5 μm with 1 pulse (4 times of increasing value).
When the setting is “20”, the output waveform of encoder frequency division pulse is shown in the
“above figure”.
The upper frequency limit value of encoder signal output is 4Mpps (
4 times of increasing value
), so
