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12 CONTROL SUB FUNCTIONS
1) Servo amplifier
2) Servomotor
3) Detector cable
4) PLC system
PLC system
QCPU
QD75
Current feed value
Machine feed value
I/O module
Current
position
change
Servomotor
(2) Preparation
Prepare the absolute position detection system taking care of the following.
Component
[2] Outline of absolute position detection data communication
As shown in Fig. 12.33 System block diagram, the detector comprises an
encoder for detecting its position in one rotation in addition to the A, B, Z phase
signal for position control in normal operation and a cumulative rotation counter
for detecting the number of rotations.
The absolute position detection system detects the absolute position of the
machine constantly and stores it with the backup of the battery irrespective of
whether the PLC system power is turned ON/OFF. Thus, once the OP initial
setting is carried out at the time of installation of the machine, the OPR is not
required even when the power is later turned ON. The restoration can be carried
out easily when an instantaneous power interruption or emergency stop occurs.
In addition, because the absolute position data is backed up by a super
condenser built in the detector, the absolute position data will be stored for a
specified time even if the cable is disconnected or broken.
Pulse train
command
Input
Output
1 pulse/rev cumulative rotation
counter
Super condenser
Counter in one rotation
A.B.Z phase signal
Detector
Fig. 12.33 System block diagram
• Install the battery to the servo amplifier.
• Validate the absolute position detection function of the
servo amplifier.
Refer to the servo amplifier manual for details.
• Use a servomotor with absolute position detector.
Refer to the servomotor manual for details.
• Add a battery power connection cable (BAT/LG signal) for
wiring the incremental detector cable.
Refer to the cable operation manual for details.
• Carry out the transmission and receiving of the absolute
position detection data by the I/O modules (input 3
points/output 3 points).
• Use the "16 point input module" and "16 point output
module".
Servo amplifier
OP data
2
E PROM memory
LS0
1X0
Backup at
power OFF
LS
Speed
detection
Battery
12 - 51
MELSEC-Q
Details
Position
Current
control/
position
speed
control
1X
Detection of
position in one
rotation
High-speed serial
communication
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Troubleshooting
