Dog Switch - Mitsubishi FX-1PG User Manual

FX-1PG/FX -1PG PULSE GENERATOR UNIT
2N
6.1.1

DOG Switch

< DOG switch for returning to home position >
Limit switch Limit switch
for limit for near point
detection detection (Dog switch)
LSN LSD
Returning to
home position
Motor
• A dog whose length is L is fixed to a table driven in
the left and right direction by a servo motor via a
ball thread.
• When the table moves in the home position return
direction, the dog is in contact with the limit switch
(LSD) for near point detection, and the LSD is
actuated.
• The LSD is turned ON from OFF when the BFM #3
b12 is set to 0, and turned OFF from ON when the
BFM #3 b12 is set to 1.
• The home position return direction is determined by
the BFM #3 b9 (rotation direction) and b10 (home
position return direction).
• The limit switch LSD is often referred to as dog
switch. The actuation point of the dog switch is
rather dispersed.
L
DOG
Table
Ball thread
OUTLINE OF OPERATION MODES
It is not always actuated at one
same point, which will affect the
r e p e a t a b i l it y o f t h e h o m e
position return operation.
On the other hand, the servo amplifier outputs one
zero point signal PG0 (Z phase signal 0P) for each
revolution of the servo motor.
For example, if the table is moved by 1 mm per
revolution of the servo motor, one PG0 signal is output
for every 1 mm movement of the table.
Accordingly, if the dog switch is adjusted so that it is
actuated within the interval between two PG0 signals
and the PG0 signal is used for returning to the home
position, dispersion in actuation of the dog switch can
be neglected. The repeatability of the home position
return operation is assured.
Dispersion in actuation
of the dog switch
6
PG0 signal
6-2