User`s manual

Product Overview
GFK-1742A Chapter 1 Product Overview 1-11
1
Follower Mode Operation
Figure 1-3 is a simplified diagram of the
Follower
mode Position Loop. It is similar to the
Standard
mode Position Loop (see previous page) with the addition of a Master Axis input. The
Master Axis input is an additional command source producing a Master Axis Position and Master
Axis Velocity. Master Axis Position is summed with
Commanded Position
from the axis
Command Generator. Master Axis Velocity is summed with the
Commanded Velocity
(Velocity
Feedforward) output of the axis Command Generator.
Therefore, the servomotor’s position and
velocity is determined by the sum of the Command Generator output and Master Axis input.
The Command Generator and Master Axis input can operate simultaneously or independently to
create Servo Axis motion.
The DSM314 allows several sources for the Master Axis input:
•
Axis 1 Commanded Position
•
Axis 1 Actual Position (Axis 1 Encoder)
•
Axis 2 Commanded Position
•
Axis 2 Actual Position (Axis 2 Encoder)
•
Axis 3 Commanded Position
•
Axis 3 Actual Position (Axis 3 Encoder)
•
Axis 4 Commanded Position
•
Axis 4 Actual Position (Axis 4 Encoder)
The ratio at which a Servo Axis follows the Master Axis is programmable as the ratio of two
integer numbers. For example, a Servo Axis can be programmed to move 125 Position Feedback
units for every 25 Master Axis Position units. Each time the Master Axis Position changed by 1
position unit, the Servo Axis would move (125 / 25) = 5 Position Feedback units.
POS LOOP
GAIN
COMMAND
GENERATOR
CMD VELOCITY (Feed Forward)
CMD
POSITION
POSITION
FEEDBACK
POS
ERROR
SERVO
VEL
CMD
SERVO
AMPLIFIER
MOTOR
ENCODER
JOG
MOVE
AT VEL
MOTION
PROGRAM
+
-
+
+
+
POSITION
TO
VELOCITY
MASTER
AXIS
POSITION
+
MASTER
AXIS
ENCODER
MASTER
AXIS
VELOCITY
Figure 1-3. Simplified Follower Mode Position Loop with Master Axis Input