Mitsubishi Electric 800 Series Instruction Manual page 531

(A) Application parameters
Power failure signal (Y67 signal)
• Y67 signal turns ON when the output is shut off due to detection of power failure (power supply fault) or undervoltage, or
the power failure time deceleration-to-stop function is activated.
• To use the Y67 signal, assign the function by setting "67 (positive logic)" or "167 (negative logic)" in any of Pr.190 to Pr.196
(Output terminal function selection).
NOTE
• If the "output frequency - Pr.262" at undervoltage or at power failure is a negative value, it is regarded as 0 Hz. (DC injection
brake operation is performed without deceleration.)
• The power failure time deceleration stop function is disabled during a stop or when the breaker is tripped.
• The Y46 signal turns ON if an undervoltage occurs even if a deceleration at a power failure has not occurred. For this reason,
the Y46 signal is sometimes output instantaneously when the power supply is turned OFF. This is not a fault.
• When the power failure time deceleration stop function is selected, undervoltage protection (E.UVT), instantaneous power
failure protection (E.IPF) and input phase loss protection (E.ILF) are not invalid.
• When the load is high during PM sensorless vector control, an undervoltage sometimes causes the coasting stop.
• Changing the terminal assignment using Pr.178 to Pr.189 (Input terminal function selection) and Pr.190 to Pr.196
(Output terminal function selection) may affect the other functions. Set parameters after confirming the function of each
terminal.
CAUTION
 Even if the power failure time deceleration stop function is set, some loads might cause the inverter
to trip and the motor to coast.
The motor will coast if sufficient regenerative power is not obtained from the motor.
Parameters referred to
Pr.12 DC injection brake operation voltage
Pr.20 Acceleration/deceleration reference frequency, Pr.21 Acceleration/deceleration time increments
Pr.30 Regenerative function selection
Pr.57 Restart coasting time
Pr.190 to Pr.196 (Output terminal function selection)
Pr.872 Input phase loss protection selection
530
PARAMETERS
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page 515
page 370
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page 269