Mitsubishi Electric MELSERVO-J3W Series, Instruction Manual

Page: 242 / 500

12. ABSOLUTE POSITION DETECTION SYSTEM
12 - 1
12. ABSOLUTE POSITION DETECTION SYSTEM
CAUTION
If an absolute position erase alarm (25.1) or absolute position counter warning
(E3. ) has occurred, always perform home position setting again. Not doing so can
cause runaway. Not doing so may cause unexpected operation.
POINT
If the encoder cable is disconnected, absolute position data will be lost in the
following servo motor series. HF-MP, HF-KP, HF-SP, HC-UP, HC-LP and HF-JP.
After disconnecting the encoder cable, always execute home position setting and
then positioning operation.
12.1 Features
For normal operation, as shown below, the encoder consists of a detector designed to detect a position within
one revolution and a cumulative revolution counter designed to detect the number of revolutions.
The absolute position detection system always detects the absolute position of the machine and keeps it battery-
backed, independently of whether the servo system controller power is on or off.
Therefore, once home position return is made at the time of machine installation, home position return is not
needed when power is switched on thereafter.
If a power failure or a fault occurs, restoration is easy.
MR-BAT 8
CYC0
Current position
Home position data
LS0
Position data
LS
Detecting the
number of
revolutions
CYC
Detecting the
position within
one revolution
Servo motor
1 pulse/rev accumulative revolution
counter
Within one-revolution counter
High speed
serial
communication
Servo amplifier Servo system controller
MR-BTCASE
P
o
si
tion con
trol
S
peed
co
ntr
o
l