
B–63523EN–1/03
7. FEEDRATE CONTROL/ACCELERATION
AND DECELERATION CONTROL
960
The function of linear acceleration/deceleration before interpolation in-
creases or decreases the feedrate specified in the tangential direction.
If the feedrate command is changed
D Type A
Acceleration/deceleration is started in the block in which a new feedrate
command is specified.
D Type B (Set the FWB bit (bit 0 of parameter No. 1602) to 1.)
Deceleration: Deceleration is started in a prior block such that decelera-
tion is completed before the beginning of the block in
which a new feedrate command is specified.
Acceleration: Acceleration is started in the block in which a new fee-
drate command is specified.
B type
A type
<Deceleration Example> <Acceleration Exapmle>
Command feedrate
Feedrate after accel-
eration/deceleration
before interpolation
Command feedrate
Feedrate after accel-
eration/deceleration
before interpolation
Feedrate
Point P
Time
F3
F2
F1
N1 N2
Feedrate
Time
F3
F2
F1
N1 N2
With B type, to decelerate from F3 to F2,
deceleration must start with point P.
If an overtravel alarm occurs during linear acceleration/deceleration
before interpolation, the movement is decelerated and stopped. As
deceleration and stop are performed after the alarm occurs, the tool will
overrun by an amount equal to the distance required for the deceleration.
The actual overrun depends on the feedrate when the overtravel alarm
occurs.
The distance can be minimized by starting deceleration in advance, such
that the feedrate has fallen to the value specified in parameter No. 1784
when an overtravel alarm occurs. Because deceleration is executed such
that the feedrate at the time an overtravel alarm occurs does not exceed
the feedrate specified in the corresponding parameter, deceleration may
be completed earlier. After deceleration is completed, the feedrate
specified in the parameter is maintained.