
B–62073E–1/04 2. INTERFACE BETWEEN CNC AND PMC–NA OR NB
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(3) Override
While an axis is moving as specified by the velocity command, the feedrate can be overridden by the over-
ride signal.
The override signal is provided for each axis (OVnX7 to OVnX0).
100%
160% 80%
Feed rate
Time
Override
Time
160%
100%
160%
80%
Fig. 2.3.81 (e) Override
NOTE The feedrate can be overridden by the PMC axis control command as well as the override
signal. These two override functions cannot be used at the same time. A parameter is provided
to select the override function to be used.
(4) Acceleration/deceleration
The speed specified by the PMC axis control function can be increased or decreased.
When a movement starts and ends, this function linearly increases and decreases a specified feedrate.
This allows the tool to be started and stopped smoothly. Moreover, when a different feedrate is specified,
the function automatically increases or decreases the speed smoothly.
If a command to rotate the tool about the rotation axis in the opposite direction is specified, the acceleration/
deceleration function for the speed specified by the PMC axis control function first linearly decrease s the
feedrate to zero. Then, the function linearly increases the feedrate to the specified speed. If a different fee-
drate in the same direction is specified, the current feedrate is linearly increased or decreased to the speci-
fied feedrate without being decreased to zero.
Feedrate
Time
V
1
V
2
V
3
V
4
Fr
Tr
Fr
Tr
Fr : Acceleration/deceleration rate (parameter 1644)
Tr : Acceleration/deceleration time (parameter 1645)