
B--65245EN/02
3. PERIPHERAL EQUIPMENT CONTROLHANDLING
95
(i) L
DW
: Deceleration dog width (user unit)
L
DW
>(V
R
((T
R
/2) + 11 + T
S
)+4V
L
× T
S
)/60000
V
R
: Rapid traverse rate (user unit/min)
T
R
: Rapid traverse time constant (msec)
T
S
: Servo time constant (msec)
V
L
: Feedrate after deceleration (user unit/min)
(ii) L
DA
: Distance between the deceleration limit switch release point
and reference position
L
DA
= Travel distance equivalent to a half rotation of the motor
The condition above does not include limit switch operation
variation. Consider such variation into consideration when
installing a limit switch.
To perform reference position return according to the sequence mentioned
here, the machine must be fed once in the reference position return
direction at such a feedrate that the servo position deviation exceeds 128,
before the first reference position return operation. A servo position
deviation (E) is determined from a feedrate (F) and servo loop gain (G).
E=(F/G)× (1/U)
E: Servo position deviation (user unit)
F: Feedrate (user unit/sec)
U: Detection unit (user unit)
G: Servo loop gain
In general, the detector unit is one user unit.
When the machine is fed at a rapid traverse rate of 6000000 user
units/min, the servo position deviation in t he steady state is as follows if
the position loop gain is 30:
E = ((6000000/60)/30) × (1/1) = 3333
On the contrary, such a feedrate that the servo position deviation is 128
is as follows if the detection unit is one user unit, and the servo loop gain
is 30:
F = 128 × 30 × 60 = 230,400 (user unit/min)
This means t hat when the servo loop gain is 30, and the detection unit is
one user unit, the machine needs to be fed in the reference position return
direction at a feedrate of 230400 user units/min or more before reference
position ret urn. A servo position deviation present when the machine is
actually fed can be checked using DGN No. 032.
NOTE
When this function is used, the high--speed interlock signal
is disabled.
3.5.1.3
Tip