Mitsubishi Electric MELSERVO MR-J2-A Product Specifications And Installation Manual page 159

5.ABSOLUTE POSITION DETECTION SYSTEM
2) Applicable general-purpose programmable controller units
Positioning Unit
AD71 · AD71S2 · AD71S7
A1SD71S2 · A1SD71S7
AD75P · A1SD75P
FX–1PG · FX–1GM
FX(E)–20GM · FX–10GM
Note: 1. The A0J2CPU cannot be used.
2. For the availability of the units not listed above, consult Mitsubishi.
3. The absolute position detection program is not required for the FX-1GM,
FX(E)-20GM and FX-10GM.
Configuration
General-purpose
programmable controller
AD75
or the like
I/O
(4) Overview of absolute position detection data communication
1) System block diagram
As shown below, the encoder consists of not only the position controlling A, B and Z phase
signals but also a counter designed to detect a position within one revolution and a cumulative
revolution counter designed to detect the number of revolutions.
Whether the general-purpose programmable controller power is on or off, the absolute position
detection system keeps the absolute position of the machine detected and battery-backed.
Therefore, once the home position has been set during machine installation, dog type zeroing
is not needed thereafter at power-on, ensuring ease of recovery after a power failure or
fault.
Also, battery-backed by the super capacitor in the encoder, absolute position data can be
held if cable disconnection or cable breakage occurs within the specified time (data holding
time during battery replacement).
General-purpose programmable controller
CPU Positioning unit
Current position
I/O unit
Current
position
read
AX40 · 41 · 42
AY40 · 41 · 42
FX2–32MT
Servo amplifier
CN1A
CN1B CN2
Pulse train
Zeroing data
command
EEPROM memory
Backup at
power off
Input
Output
Battery
Servo motor
1P/rev Cumulative revolution
counter
Super capacitor
Within one-revolution counter
A, B, Z phase signals
(Encoder)
5– 3
I/O Unit
Battery
Servo motor
Servo amplifier
Current
LSO
position
1XO
LS
Detection of
Speed
position within
detection
one revolution
MR–BAT
Speed control
Position control
1X
High-speed serial
5