
B–63503EN–1/01
7. FEEDRATE CONTROL/ACCELERATION
AND DECELERATION CONTROL
316
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.
Deceleration is performed when the following condition is
satisfied:
Distance to stored stroke limit 1
for each axis
Distance needed to reduce the cur-
rent feedrate (tangential feedrate)
to that specified in parameter No.
1784
<
The overrun is calculated as follows:
Overrun
Ąx
[FIX (
FOT
F
T
8
) ) 1.5]
2
F
T
1875
F : Maximum cutting feedrate in linear acceleration/deceleration before
interpolation (parameter No. 1770)
T : Time needed to attain the maximum cutting feedrate in linear
acceleration/deceleration before interpolation (parameter No. 1771)