
B–63443EN/02
10. REFERENCE POSITION RETURNPMC INTERFACE
163
Point at which
*DEC1 turns to
“0”
Deceleration
region
Reference position
Fig.10.1 (d)
After deceleration, a parameter (No. 1425) can be used to set a low
constant speed for each axis within the range of 6 to 24,000 mm/min or
0.6 to 960 inches/min.
Automatic reference position return to zero point return direction by G28
is performed by the same sequence as manual reference position return
only if manual/ automatic reference position return has never been
performed after turning power on, after emergency stop or after releasing
servo alarm. Once the reference position return is performed by the above
sequence, automatic reference position return is performed the same as
positioning to the reference position at rapid traverse and does not follow
the sequence described here, and the starting position of G28 command
is not limited.
(b) Deceleration limit switch installation conditions
Installation of the deceleration limit switch for reference position
return must meet the following conditions (Fig. 10.1 (e))
V
L
Feedrate
Return direction
Deceleration limit
switch operation point
Deceleration limit
switch released point
L
DA
L
DW
Reference position
V
R
Fig.10.1 (e)
(1) L
DW
: Deceleration dog width (mm or inch)
L
DW
u
V
R
(
T
R
2
) 30 ) T
S
) ) 4V
L
.T
S
6000
V
R
: Rapid traverse (mm/min or inch/min)
T
R
: Rapid traverse time constant (msec)
T
S
: Servo time constant (msec)
V
L
: Speed after deceleration (mm/min or inch/min)