
FANUC AC SPINDLE MOTOR a series
2. FUNCTION EXPLANATION
B–65160E/02
58
(c) t
3
is the time required for the motor to rotate zero to one turns at
orientation speed Nori [min
–1
].
0 60 Nori x t
3
x 1 60 Nori
N 0 x t
3
x
1
PG Rori
(d) t
4
is the time from the start of deceleration until orientation has
been completed.
Let the orientation completion width be within +10 pulses. Then,
t
4
can be calculated as follows:
t
4
+
1
PG
In
4096 Rori
10
(e) Therefore, the orientation time t [sec] (= t
1
+ t
2
+ t
3
+ t
4
) can be
expressed as follows:
t
1
)
1
PG Rori
)
1
PG
ln
4096 Rori
10
x t x t
1
)
3
PG Rori
)
1
PG
ln
4096 Rori
10
(2) Once the one–rotation signal has been detected (second and
subsequent orientations)
(a) Once the one–rotation signal has been detected, the time required
to detect the signal is no longer necessary. Therefore, when
orientation is started from the rotating state, orientation time t
[sec] (= t
1
+ t
3
+ t
4
) is expressed as follows:
t
1
)
1
PG
ln
4096 Rori
10
x t x t
1
)
1
PG Rori
)
1
PG
ln
4096 Rori
10
(b) Whenever orientation is started from the stop state, orientation
must be completed and the stop state entered within one rotation.
In this case, the orientation time t [sec] is expressed as follows:
0 x t x
1 * Rori
PG Rori
)
1
PG
ln
4096 Rori
10
(3) Calculation examples
Time required to achieve the orientation speed t
1
= 0.5 [sec]
Position gain PG = 20 [sec
–1
]
Motor speed limit for orientation Rori = 0.33 (= 33%)
(a) Orientation time before the one–rotation signal has been detected
0.5 )
1
20 0.33
)
1
20
ln
4096 0.33
10
x t x 0.5 )
3
20 0.33
)
1
20
ln
4096 0.33
10
N 0.896 [sec] x t x 1.196 [sec]
(b) Orientation time when orientation is started from the rotating
state (once the one–rotation signal has been detected)
0.5 )
1
20
ln
4096 0.33
10
x t x 0.5 )
1
20 0.33
)
1
20
ln
4096 0.33
10
N 0.746 [sec] x t x 0.896 [sec]
(c) Orientation time when orientation is started from the stop state
(once the one–rotation signal has been detected)
0 x t x
1 * 0.33
20 0.33
)
1
20
ln
4096 0.33
10
N 0 [sec] x t x 0.346 [sec]