Mitsubishi Electric Melservo-J4 Instruction Manual page 49

Alarm No.: 25 Name: Absolute position erased
 The absolute position data is faulty.
Alarm content
 Power was switched on for the first time in the absolute position detection system.
 After the scale measurement encoder was set to the absolute position detection system, the power was
switched on for the first time.
Detail Detail name Cause
No.
25.2 Scale (1)
measurement measurement encoder
encoder - was set to the absolute
Absolute position detection
position erased system, the power was
switched on for the first
time.
(2) The battery was
removed (replaced)
when the control circuit
power supply was off.
(3) The power was turned
off with the battery
disconnected from CN4.
(4) The battery voltage is
low. The battery is
consumed.
(5) The voltage has
dropped greatly in the
encoder cable wired to
the battery.
(6) A battery cable is
malfunctioning.
(7) There is a loose
connection of the
encoder cable on the
scale measurement
encoder side.
(8) The servo amplifier is
malfunctioning.
(9) The scale measurement
encoder is
malfunctioning.
Check method
After the scale Check if this is the first
time to switch on the
power after the scale
measurement encoder
was set to the absolute
position detection
system.
Check if the battery was
removed when the
control circuit power
supply was off.
Check if the power was
turned off in this state.
Check the battery
voltage with a tester.
Check if a recommended
cable is used for the
encoder cable.
Check for the loose
connection with a tester.
Check for the loose
connection with a tester.
Measure the voltage on
the scale measurement
encoder side.
Replace the servo
amplifier, and then check
the repeatability.
Replace the scale
measurement encoder,
and then check the
repeatability.
Check result
This is the first time.
This is not the first time.
It was removed.
It was not removed.
It was turned off.
It was not turned off.
It is less than 3 V DC.
It is 3 V DC or more.
It is not used.
It is used.
It has a failure.
It has no failure.
It has a failure.
It has no failure.
It is not repeatable.
It is repeatable.
It is not repeatable.
1 TROUBLESHOOTING FOR SERVO AMPLIFIER (DRIVE UNIT)
Action Target
Check that the battery is [B]
mounted correctly, and [WB]
make home position [GF]
return.
Check (2).
Check that the battery is
mounted correctly, and
make home position
return.
Check (3).
Check that the battery is
mounted correctly, and
make home position
return.
Check (4).
Replace the battery.
Check (5).
Use a recommended
wire.
Check (6).
Replace the battery
cable.
Check (7).
Repair or replace the
encoder cable.
Check (8).
Replace the servo
amplifier.
Check (9).
Replace the scale
measurement encoder.
1.4 Remedies for alarms
1
47