Mitsubishi Electric FR-A820-00046 Instruction Manual page 850

(G) Control parameters
Pre-excitation signal (LX signal)
● When the Pre-excitation/servo ON (LX) signal is turned ON at the time of Real sensorless vector
control, vector control, or PM sensorless vector control, pre-excitation (zero speed control, servo
lock) will be ON while stopped.
● To input the LX signal, set "23" in any of Pr. 178 to Pr. 189 (input terminal function selection) to
assign the function.
Fig. 5-332:
NOTES 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.
Performing pre-excitation (LX signal and X13 signal) under torque control (Real sensorless vector
control) may start the motor running at a low speed even when the start command (STF or STR) is
not input. The motor may run also at a low speed when the speed limit value = 0 with a start com-
mand input. It must be confirmed that the motor running will not cause any safety problem
before performing pre-excitation.
Note that during the pre-excitation operation, a voltage is applied to the motor even with the
FWD/REV indicator OFF on the operation panel.
When offline auto tuning (Pr. 96 "Auto tuning setting/status" = "1, 11, 101") is executed at the time
of pre-excitation operation, pre-excitation is disabled.
CAUTION:
E
Do not set Pr. 11 to "0, 8888" and Pr. 12 to "0" at the time of orientation operation. The motor
may not stop properly.
Install a mechanical brake to make an emergency stop or to stay stopped for a long time.
After the machine comes to a full stop and the motor is fixed by the mechanical brake, turn OFF
the LX signal (pre-excitation).
Parameters referred to
Pr. 13
Pr. 71
Pr. 80
Pr. 178 to Pr. 182
Pr. 422
5 - 670
Zero speed control
Servo lock
Normal operation
LX signal
Selection of pre-excitation using an external signal
Starting frequency
Applied motor
Motor capacity
(input terminal function selection)
Position control gain
Pr. 10
"Operation
frequency"
Pr. 11 Normal operation
"Operation
time" ON
Parameters
Time
I001560E
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