5 Operation
79 SD780 Series Servo Technical Manual
Adjustment of instruction offset
When analog speed control is used, even if the command is 0V, the servo motor may rotate at a
slight speed. This is because there is a slight deviation in the instructions inside the servo unit. This
slight deviation is called “offset”.
There are two methods of automatic adjustment and manual adjustment of offset adjustment.
Automatic adjustment is automatic adjusting command offset (Fn100) and manual adjustment is
manually adjusting command offset (Fn101). For details, see “Auxiliary Functions”.
Input voltage range
0V~± 10V
Setting range 1.5V~30V corresponding
to rated speed
Maximum input voltage
+10V
Rated Speed
Motor speed
r/min
-
30
-
10
-
6
-
1.5
1.5
6
10
30
Minimum input voltage
-
10V
Factory setting
Voltage-V
Motor speed
Offset
V-REF Voltage
Motor speed
After offset adjustment
V
-
REF Voltage
Cautions
！
1. For automatic adjustment, be sure to adjust the command bias amount in the state of servo OFF and the
upper computer (PLC, knob, etc.) giving 0v voltage command.
2. When adjusting manually, observe the operation of the motor while adjusting in the state of servo ON.
3. If the factory setting is restored, the offset adjustment value will not be initialized.
