Specifications

1 - 7
(1) Principe of position commands
The total No. of pulses required to move the designated distance is obtained in the
following manner.
x
=
*The No. of pulses required for the motor to rotate once is the
"encoder resolution" shown in the motor catalog specifications.
Total No. of pulses required to
move designated distance
Designated distance
No. of pulses required
for motor to rotate once
Machine (load) side moving distance
for each motor rotation
When this total No. of pulses is issued from the QD75 to the servo amplifier, control to
move the designated distance can be executed.
The machine side moving amount produced by outputting one pulse to the servo
amplifier is called the "moving amount per pulse". This value is the minimum value for
the workpiece motion, and represents the electrical positioning accuracy.
(2) Principe of speed commands
A speed command is controlled by the frequency of pulses output from the QD75
to a drive unit.
Positioning
module
Servo
amplifier
Servo
motor
Detector
Pulses generated by detector
Speed = Pulses frequency
Moving distance = No.of pulses
Feedback pulses = Pulses generated by detector
Pulse frequency [pps]
A
ta tc
0.4 0.41.2
Travel time t = 2
(s)
tb
This area is the total No.
of command pulses.
Fig. 1.1 Relationship between position control and speed control
POINT
The QD75 controls positions with "total No. of pulses” and speeds with "pulse frequency".