System philosophy
HARDWARE REFERENCE MANUAL
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2.3
Servo system principles
The servo system used by and the internal operation of the TJ1-
MC__ are briefly described in this section.
2.3.1
Semi-closed loop system
The servo system of the TJ1-MC__ uses a semi-closed or inferred
closed loop system. This system detects actual machine
movements by the rotation of the motor in relation to a target value.
It calculates the error between the target value and actual
movement, and reduces the error through feedback.
2.3.2
Internal operation of the TJ1-MC__
fig. 15
Inferred closed loop systems occupy the mainstream in modern
servo systems applied to positioning devices for industrial
applications. The figure shows the basic principle of the servo
system as used in the TJ1-MC__.
1. The TJ1-MC__ performs actual position control. The main input
of the controller is the Following Error, which is the calculated
difference between the demand position and the actual
measured position.
2. The Position Controller calculates the required speed reference
output determined by the Following Error and possibly the
demanded position and the measured position. The speed
reference is provided to the Servo Driver.
3. The Servo Driver controls the rotational speed of the servo
motor corresponding to the speed reference. The rotational
speed is proportional to the speed reference.
4. The rotary encoder generates the feedback pulses for both the
speed feedback within the Servo Driver speed loop and the
position feedback within the TJ1-MC__ position loop.
The labels in the figure are:
A. TJ1-MC__.
B. Servo system.
A
B
C
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I51E-EN-03.book Seite 27 Donnerstag, 28. Juni 2007 1:05 13