Mitsubishi Electric FR-A800 Series Instruction Manual page 720

NOTE
• When operating under controls other than Real sensorless vector control, the inverter will immediately shutoff the output when
the X74 signal is turned ON.
• Even under Real sensorless vector control, the inverter will immediately shutoff the output when the X74 signal is turned ON
during the automatic restart after instantaneous power failure and online auto tuning during the start up.
• If another output-shutoff trigger (inverter fault, turn-ON of the MRS signal, etc.) occurs during the magnetic flux decay
operation, the magnetic flux decay operation is terminated, and the output is shut off immediately.
• Unlike the MRS signal, voltage is output during the magnetic flux decay output shutoff operation, so take caution on electric
shocks.
• When the release timing of the mechanical brake is too fast, the motor shaft may be rotated by dropping or external force.
When the release timing is too late, the overcurrent prevention operation, stall prevention operation, or electronic thermal O/
L relay function may be activated. Perform release of the mechanical brake matching the equipment using the Output
frequency detection (FU) signal or Output current detection (Y12) signal.
• Changing the terminal assignment using Pr.178 to Pr.189 (Input terminal function selection) may affect the other functions.
Set parameters after confirming the function of each terminal.
 Braking operation selection under Vector control or PM sensorless
vector control (Pr.802, Pr.1299)
• Pr.802 Pre-excitation selection to select the braking operation when the pre-excitation is performed from either zero speed
control or servo lock.
• Turning ON the RT signal enables the second pre-excitation selection (when Pr.450 ≠ "9999").
Pr.802
(Pr.1299)
setting
0 (initial value)
1
• The relation between the DC injection brake operation and pre-excitation operation is as follows.
Control method
V/F control
Advanced magnetic flux vector
control
Real sensorless vector control
Vector control
PM sensorless vector control,
low-speed range high-torque
mode disabled
PM sensorless vector control,
low-speed range high-torque
mode enabled
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Pre-
excitation
Even under a load, the inverter does not rotate the motor and holds 0 r/min. However, it will not return to
Zero speed its original position when the shaft moves due to external force.
control This setting is invalid during position control. The inverter operates according to this setting only during
speed control.
Even under a load, the inverter holds the position of the motor shaft. When the shaft moves due to external
force, it will return to its original position after the external force is removed.
Servo lock
To perform the position control, this loop gain can be adjusted using Pr.422 Position control gain
(Pr.1298 Second position control gain).
Control
mode
— —
— —
—
—
Speed
—
—
—
Torque
—
0
Speed
1
Torque —
Position —
Speed —
0
Speed
1
Position —
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Description
Pr.802
Pr.850 Deceleration stop
(Pr.1299)
— DC injection brake
— DC injection brake
0 DC injection braking
1 Zero speed
Magnetic flux decay
2
output shutoff
0 DC injection braking
1 Zero speed
Magnetic flux decay
2
output shutoff
— Zero speed
— Servo lock
— Zero speed
— —
— DC injection brake
Zero speed
—
Servo lock
— —
X13-ON
LX-ON
(Pr.11 = "8888")
— DC injection brake
— DC injection brake
Zero speed Zero speed
Zero speed Zero speed
Zero speed Zero speed
Zero speed Zero speed
Zero speed Zero speed
Servo lock Servo lock
Zero speed Zero speed
Servo lock —
— —
Zero speed
—
Servo lock
Servo lock —
5. PARAMETERS
5.16 (G) Control parameters
1
2
3
4
5
6
7
8
9
10
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