Mitsubishi Electric MELSEC Q Series Programming Manual page 389

6 POSITIONING CONTROL
(1) Travel value after proximity dog ON
(a) The travel value after proximity dog ON is set to execute the count method
home position return.
(b) After the proximity dog ON, the home position is the first zero-point after
travel by the setting travel value.
(c) Set the travel value after proximity dog ON more than the deceleration
distance from the home position return speed.
Example
The deceleration distance is calculated from the speed limit value, home position
return speed, creep speed and deceleration time as shown below.
[Home position return operation]
Speed limit value : V
Home position return speed : V
Real deceleration time : t=T
[Deceleration distance (shaded area under graph)]
1 V
Z
=
2 1000
V T
Z B
=
2000 V
10 10
3
=
2000
= 75 . . . . . . Set 75 or more
POINT
A home position return must be made after the servo motor has been rotated more
than one revolution to pass the axis through the Z-phase (motor reference position
signal).
For a proximity dog method or count method home position return, the distance
between the point where the home position return program is started and the
deceleration stop point before re-travel must be such that the servo motor is rotated
more than one revolution to pass the axis through the Z-phase.
When a data set method home position return is made in an ABS (absolute
position) system, the servo motor must also have been rotated more than one
revolution by JOG operation or the like to pass the axis through the Z-phase.
(Note) : When "1 : No servo motor Z-phase pass after power ON" is selected in the
"function selection C-4 (PC17)" of servo parameter (expansion setting
parameter), even if it does not pass zero point, the home position return
can be executed and restrictions are lost.
=200kpps
P
=10kpps
Z
V
Z
B
V
P
T
B
t
Converts in speed per millisecond
V
Z
P
300 10 10
3
200 10
3
6 - 202
Creep speed : V =1kpps
C
t
Deceleration time : T =300ms
B