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93
DESCRIPTIONDESIG.DATE
Power Failure Backup Module
Descriptions
A-53866E-464
7.1.4 Notes on Setting the Parameters for the Retract function at power failure
The retract amount parameter must be set to a value equal to or greater than twice the travel distance
necessary for preventing the workpiece and the tool from interfering with each other.
Supplementary explanation
Changes in the speed of travel along the retract axis from the time retraction is started until it is
completed are divided into three areas shown in the figure below.
Area 1
Area from the start of retraction to the point the retract speed is reached.
Area 2
Area in which travel is at the retract speed.
Area 3
Area in which deceleration is performed on the retract axis.
Time
Retract axis travel speed
Area 1 Area 2 Area 3
Completion of retraction
of workpiece and tool
Completion of retraction
0
In areas 1 and 2, energy is supplied from sub module C for movement along the retract axis. In
area 3, the energy resulting from deceleration on the retract axis returns to the amplifier as electric
energy. In normal operation, the energy resulting from the deceleration of the motor is regenerated
into power, but in the event of a power failure, the DC link voltage increases because there is no route
for regenerating energy into power, possibly generating the DC link high voltage alarm depending on
the condition. If the alarm is generated, synchronization is no longer maintained, possibly causing the
workpiece and the tool to be damaged. For this reason, the workpiece and the tool must have been
retracted to a position where they do not interfere with each other before area 3 is reached.
If sub module R is connected, the energy resulting from deceleration along the retract axis will be
processed by sub module R, so that the DC link high voltage alarm will not be generated in area 3.
For this reason, if sub module R is connected, the retract amount parameter may be set to the same
value as the travel distance necessary for preventing the workpiece and the tool from interfering with
each other.