
B-65280EN/05 FANUC AC SPINDLE MOTOR αi series 3.I/O SIGNALS (CNC ↔ PMC)
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3.2.3 Details of Output Signals
(a) Spindle alarm signal (ALMA)
(1) When continuation of spindle motor operation becomes
impossible, the power to the spindle motor is turned off to stop
the spindle motor.
(2) At the same time, alarm signal ALMA is set to 1. For the
meaning of the alarm, check the indicator of the spindle
amplifier.
(3) Use the alarm signal output to reset the command signals sent to
the spindle amplifier (speed command, forward and reverse
rotation commands, and spindle orientation command). Unless
the reset state has been entered (the signals issued from the PMC
have been all cleared), the spindle motor may rotate when the
alarm on the spindle amplifier is released, which presents a
dangerous situation.
(4) At the same time when the alarm signal is output, the power to
the spindle motor is turned off, and the spindle motor coasts.
Therefore, it is necessary to enter the feed hold state by setting
the emergency stop state on the CNC or power magnetics
cabinet.
(5) When the alarm state is entered, ALMA is set to 1. While the
alarm signal is 1, the spindle motor is placed in the coast state
regardless of external commands.
(6) The following diagram shows the relationship between the alarm
signal and alarm reset signal:
Spindle orientation
command ORCMA
Usable
Not operated even when command
is issued
(Stopped)
Motor rotation speed
Remove cause of alarm
(Alarm)
ALMA
Motor operation
Spindle amplifier
control output signal
0
0 0
1
1
(Alarm reset)
ARSTA
Forward/reverse rotation
signal
SFRA (SRVA)
Spindle control
si
nals
Speed command