Omron CJ1W-NC271 - 12-2009, Operation Manual

Page: 300 / 687

272
PCU Control System
Section 7-1
7-1 PCU Control System
This section describes the configuration, principles, and basic information on
position control when using a control system configured with a PCU and a
W-series Servo Drive.
7-1-1 Control System Configuration and Principles
The control system configured using the PCU basically controls Servomotor
operations using the semi-closed loop method. The semi-closed loop method
detects the number of Servomotor rotations for the command value using the
rotary encoder mounted to the Servomotor, and sends this feedback as the
machine's travel distance. While calculating the deviation between the com-
mand value and actual number of Servomotor rotations, the machine is con-
trolled so that the deviation is compensated to 0.
In the PCU system configuration, a feedback system is configured in the
Servo Drive, without using feedback information for the commands sent from
the CPU Unit's ladder program to the PCU and Servo Drive.
7-1-2 Position Control
The control system configured using the PCU uses the Servo Drive's position
loop to perform position control. The PCU achieves positioning by using the
Servo Drive's position control functions together with control units and coordi-
nate systems.
CPU Unit PCU
Se qu ence
(ladder program)
Start
I/O w ords
Stat u s
Com-
mand
interpre-
tation and
process-
ing
Com-
m
u nica-
tions
pro-
cessing
Control commands
MECHATROLI N K
comm u nications
Stat u s
N o feed b ack system config u ration
MECHATROLI N K-II
I/F Unit
Inter-
face
Command
interpreta-
tion and
position-
ing
Ser v o Dri v e
Posi-
tion
loop
Speed
loop
C u r-
rent
loop
Ser v omotor
Feed b ack system config u ration
CPU Unit PCU
Position command
value
I/O memory area
Present position
Sending command based on the positioning
coordinate system managed by Servo Drive
Monitoring the positioning coordinate
system managed by Servo Drive
MECHATROLINK
communications
Servo Drive
Positioning
Coordinate
calculations
Present
position