Mitsubishi Electric MELSERVO-J3 Series Manual page 341

Part 5: Common Reference Material
(b) Instantaneous power failure tough drive function
The instantaneous power failure tough drive function avoids [AL. 10 Undervoltage] even when an
instantaneous power failure occurs during operation. When the instantaneous power failure tough
drive activates, the function will increase the tolerance against instantaneous power failure using the
electrical energy charged in the capacitor in the servo amplifier and will change an alarm level of
[AL. 10 Undervoltage] simultaneously. The [AL. 10.1 Voltage drop in the control circuit power]
detection time for the control circuit power supply can be changed by [Pr. PX28 SEMI-F47 function -
Instantaneous power failure detection time]. In addition, [AL.10.2 Voltage drop in the main circuit
power] detection level for the bus voltage is changed automatically.
POINT
MBR (Electromagnetic brake interlock) will not turn off during the instantaneous
power failure tough drive.
When selecting "Enabled (_ _ _ 1)" for "Torque limit function selection at
instantaneous power failure" in [Pr. PX23], if an instantaneous power failure
occurs during operation, you can save electric energy charged in the capacitor in
the servo amplifier by limiting torque at acceleration. You can also delay the time
until the occurrence of [AL. 10.2 Voltage drop in the main circuit power]. Doing
this will enable you to set a longer time in [Pr. PX28 SEMI-F47 function -
Instantaneous power failure detection time].
It is not available with MR-J4W2-_B servo amplifiers.
When the load of instantaneous power failure is large, [AL. 10.2] caused by the
bus voltage drop may occur regardless of the set value of [Pr. PX28 SEMI-F47
function - Instantaneous power failure detection time].
The external dynamic brake cannot be used for compliance with SEMI-F47
standard. Do not assign DB (Dynamic brake interlock) in [Pr. PD07] to [Pr.
PD09]. Failure to do so will cause the servo amplifier to become servo-off when
an instantaneous power failure occurs.
It is not available with MR-J4W2-_B servo amplifiers.
The setting range of [Pr. PX28 SEMI-F47 function - Instantaneous power failure
detection time] differs depending on the software version of the servo amplifier
as follows.
Software version C0 or later: Setting range 30 ms to 200 ms
Software version C1 or earlier: Setting range 30 ms to 500 ms
To comply with SEMI-F47 standard, it is unnecessary to change the initial value
(200 ms).
However, when the instantaneous power failure time exceeds 200 ms, and the
instantaneous power failure voltage is less than 70% of the rated input voltage,
the power may be normally turned off even if a value larger than 200 ms is set in
the parameter.
5 - 156