Vexta EMP400 Series Operating Manual page 72

8 Program command
Two-axis linear interpolation operation
The two-axis linear interpolation operation allows linear movement toward a target position by
controlling two axes.
Since this operation applies to linear acceleration/deceleration mode, the operation will be performed
in linear acceleration/deceleration mode even if the current setting is jerk-limit control.
In a two-axis linear interpolation operation, the axis with larger movement set in the D command
becomes the main axis, while the other becomes the sub-axis. The speed of the sub-axis is calculated
from the main axis' speed and amount of movement.
Current position
About manageable coordinates
During motor operation the controller keeps track of the number of pulses that have been output.
The values of these counters are referred to as manageable coordinates. Manageable coordinates
have upper and lower limits (manageable coordinate range). If the counter value lies outside the
manageable coordinate range, the controller cannot count the number of pulses.
Incremental operation sets the movement amount based on the current position. Therefore, the
motor can operate outside the manageable coordinate range.
On the other hand, absolute operation sets the movement amount from the reference point. Therefore,
the motor does not operate if the movement violates the manageable coordinate range.
If the manageable coordinate range has been violated in absolute operation, see the section on
"Position counter overflow. Please clear Position counter." in section 10.2, "Error messages," to
reset the counter value for the number of pulses.
Incremental operation
Absolute operation
8-6
i s
a x
i n
M a
S u
b - a
x i s
Upper limit of manageable coordinates
Target position
Incremental operation sets the movement
amount based on the current position.
Therefore, the motor operates outside the
manageable coordinate range.
However, pulses above the upper limit of
manageable coordinates will not be counted.
Absolute operation sets the movement
amount from the reference point. Therefore,
the motor does not operate if the movement
violates the manageable coordinate range.