Yaskawa MP940 - Manual (Page 310)

Parameters
6.4.7 Sequence-related Parameters
6-70
Pn509
Momentary Hold Time ms
20 to 1000 The SERVOPACK turns the servomotor OFF if it detects an instan-
taneous voltage drop in the power supply. This factory setting of 20
ms means that servomotor operation will continue if power is lost
for less than 20 ms.
In the following instances, however, a Servo alarm is generated or
control is lost (equivalent to normal power OFF operation) regard-
less of the parameter setting.
• When an insufficient voltage alarm (A.41) occurs during power
loss with a large servomotor load.
• When control is lost (equivalent to normal power OFF operation)
with loss of the control power supply.
In power loss detection, the status of the main circuit power supply
is detected and OFF status is ignored so servomotor operation will
continue if the servomotor turns back ON within the time set at
parameter Pn509.
20 Speed
Torque
Position
Parameter No. Digit
Name (Setting
Range)
Details Default
Control
Modes
ｔ OFF
Power
supply
voltage Power loss
1 Pn509 setting > t OFF
Time
2 Pn509 setting t < t OFF
For 1
For 2
Servo ON
Servo OFF
Servo ON