Table of Contents
Advertisement
incremental distances for each axis. An unlimited number of incremental segments may be given
in a continuous move sequence, making the linear interpolation mode ideal for following a piece-
wise linear path. There is no limit to the total move length.
The LM command selects the Linear Interpolation mode and axes for interpolation. For example,
LM YZ selects only the Y and Z axes for linear interpolation.
When using the linear interpolation mode, the LM command only needs to be specified once
unless the axes for linear interpolation change.
Specifying Linear Segments
The command LI x,y,z,w or LI a,b,c,d,e,f,g,h specifies the incremental move distance for each
axis. This means motion is prescribed with respect to the current axis position. Up to 511
incremental move segments may be given prior to the Begin Sequence (BGS) command. Once
motion has begun, additional LI segments may be sent to the controller.
The clear sequence (CS) command can be used to remove LI segments stored in the buffer prior to
the start of the motion. To stop the motion, use the instructions STS or AB. The command, ST,
causes a decelerated stop. The command, AB, causes an instantaneous stop and aborts the
program, and the command AB1 aborts the motion only.
The Linear End (LE) command must be used to specify the end of a linear move sequence. This
command tells the controller to decelerate to a stop following the last LI command. If an LE
command is not given, an Abort AB1 must be used to abort the motion sequence.
It is the responsibility of the user to keep enough LI segments in the DMC-1600 sequence buffer
to ensure continuous motion. If the controller receives no additional LI segments and no LE
command, the controller will stop motion instantly at the last vector. There will be no controlled
deceleration. LM? or _LM returns the available spaces for LI segments that can be sent to the
buffer. 511 returned means the buffer is empty and 511 LI segments can be sent. A zero means
the buffer is full and no additional segments can be sent. As long as the buffer is not full,
additional LI segments can be sent at PC bus speeds.
The instruction _CS returns the segment counter. As the segments are processed, _CS increases,
starting at zero. This function allows the host computer to determine which segment is being
processed.
Additional Commands
The commands VS n, VA n, and VD n are used to specify the vector speed, acceleration and
deceleration. The DMC-1600 computes the vector speed based on the axes specified in the LM
mode. For example, LM XYZ designates linear interpolation for the X,Y and Z axes. The vector
speed for this example would be computed using the equation:
2
VS
=XS
The controller always uses the axis specifications from LM, not LI, to compute the speed.
VT is used to set the S-curve smoothing constant for coordinated moves. The command AV n is
the 'After Vector' trippoint, which halts program execution until the vector distance of n has been
reached.
An Example of Linear Interpolation Motion:
#LMOVE
DP 0,0
LMXY
LI 5000,0
78 • Chapter 6 Programming Motion
2
2
2
+YS
+ZS
, where XS, YS and ZS are the speed of the X,Y and Z axes.
label
Define position of X and Y axes to be 0
Define linear mode between X and Y axes.
Specify first linear segment
DMC-1600
Advertisement
Table of Contents
