Mitsubishi Electric FR-A700 Technical Manual page 292

(3) Brake operation selection [Pr. 850] during
Real sensorless vector control
You can select DC injection brake (initial value) or
zero speed control for brake operation during Real
sensorless vector control.
When [Pr. 850 = 1], zero speed control is exercised
when the frequency reaches or decreases below the
frequency set in [Pr. 10].
When the X13 signal is ON with [Pr. 11 = 8888] under
Real sensorless vector control, zero speed control is
activated regardless of setting of [Pr. 850 Brake
operation selection].
When restarting from brake operation during Real
sensorless vector control, set [Pr. 850 = 1] (zero
speed control). When the setting value is 0 (DC
injection brake), it may take about 2s until frequency
is actually output from when the start command is
input.
(4) Brake operation selection under vector
control [Pr. 802]
When pre-excitation is performed, select zero speed
control or servo lock using [Pr. 802] .
Pr. 802 Pre-
setting excitation
0
Zero speed
(initial
control
value)
1 Servo lock
Description
Even under load, an attempt is
made to maintain 0r/min to keep
the motor shaft stopped. Note
that if the shaft is overcome and
turned by external force, it does
not return to the original
position. Position control is not
exercised and only speed
control is carried out to perform
operation.
Even under load, an attempt is
made to maintain the motor
shaft position. Note that if the
shaft is turned by external force,
it returns to the original position
after the external force has gone
away. Since position control is
exercised, you can adjust this
position loop gain using [Pr. 422
Position loop gain].
(5) Operation frequency setting [Pr. 10].
After the frequency at which the DC injection brake
(zero speed control, servo lock) will be operated is
set to [Pr. 10], the DC voltage is applied (zero speed
control, servo lock) to the motor when this frequency
is reached during deceleration.
At [Pr. 10 = 9999] , DC injection brake (zero speed
control, servo lock) is operated when the speed has
decreased to the frequency set in [Pr. 13
frequency] .
Performing pre-excitation (zero speed control) under
Real sensorless vector may cause motor vibration,
etc. at deceleration to stop. To prevent this, set [Pr. 10
DC injection brake operation frequency] to 0.5Hz or
less.
The initial value of [Pr. 10] automatically changes to
0.5Hz during vector control.
(6) Operation time setting (X13 signal) [Pr. 11]
Use [Pr. 11] to set the duration period the DC injection
brake (zero speed control, servo lock) is applied.
When the motor does not stop due to large inertia (J),
increasing the setting produces an effect.
When [Pr. 11 = 0s], DC injection brake (zero speed
control, servo lock) will not operate. (At a stop, the
motor coasts.)
When [Pr. 11 = 8888], the DC injection brake (zero
speed control, servo lock) will operate when the X13
signal is turned ON. Turning the X13 signal ON
during operation will operate DC injection brake (zero
speed control, servo lock).
For the terminal used for the X13 signal input, set 13
in any of [Pr. 178 to 189] to assign the function.
When the X13 signal is ON with [Pr. 11 = 8888] under
Real sensorless vector control, zero speed control is
activated regardless of the setting of [Pr. 850 Brake
operation selection].
Under vector control, zero speed control or servo
rock is activated according to the [Pr. 802] setting.
[When Pr. 11 = 8888]
[Pr. 12]
DC injection
brake
voltage
X13 signal
STF
326
PARAMETER
Time
Time
ON ON OFF
ON
Start