System philosophy
HARDWARE REFERENCE MANUAL
11
Revision 5.0
Relative and absolute moves
fig. 3
To move a single axis either the command
MOVE
for a relative move or the
command
MOVEABS
for an absolute move is used. Each axis has its own
move characteristics, which are defined by the axis parameters.
Suppose a control program is executed to move from the origin to an axis
no. 0 (A) coordinate of 100 and axis no. 1 (B) coordinate of 50. If the speed
parameter is set to be the same for both axes and the acceleration and
deceleration rate are set sufficiently high, the movements for axis 0 and axis
1 will be as shown in the figure.
At start, both the axis 0 and axis 1 moves to a coordinate of 50 over the
same duration of time. At this point, axis 1 stops and axis 0 continues to
move to a coordinate of 100.
The move of a certain axis is determined by the axis parameters. Some
relevant parameters are:
/i
Defining moves
fig. 4
The speed profile in this figure shows a simple
MOVE
operation. Axis A is
the time, axis B is the speed. The
UNITS
parameter for this axis has been
defined for example as meters. The required maximum speed has been set
to 10 m/s. In order to reach this speed in one second and also to decelerate
to zero speed again in one second, both the acceleration as the deceleration
rate have been set to 10 m/s
2
. The total distance travelled is the sum of
distances travelled during the acceleration, constant speed and deceleration
segments. Suppose the distance moved by the
MOVE
command is 40 m,
the speed profile is given by the figure.
0
50
50
100
A
B
MOVEABS(100) AXIS(0)
MOVEABS(50) AXIS(1)
Parameter
Description
UNITS
Unit conversion factor
ACCEL
Acceleration rate of an axis in units/s
2
DECEL
Deceleration rate of an axis in units/s
2
SPEED
Demand speed of an axis in units/s
0
10
1
2
3
4
5
6
A
B
ACCEL=10
DECEL=10
SPEED=10
MOVE(40)
