Yaskawa SMC–4000 - Manual (Page 279)

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SMC–4000 User Manual
Linear Interpolation Mode
The SMC–4000 provides a linear interpolation mode for 2 or more axes. In linear interpolation mode,
motion is coordinated to maintain the prescribed vector speed, acceleration, and deceleration along the
specified path. The motion path is described in terms of incremental distances. 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 (Linear Interpolation Mode) command selects the Linear Interpolation mode and axes for
interpolation. For example, LM X selects the X axis 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 the Coordinate Plane
The SMC–4000 allows for 2 separate sets of coordinated axes for linear interpolation mode or vector
mode. These two sets are identified by the letters S and T.
To specify vector commands the coordinate plane must first be identified. This is done by issuing the
command CAS to identify the S plane or CAT to identify the T plane. All vector commands will be
applied to the active coordinate system until changed with the
CA (Coordinate Axes) command.
Specifying Linear Segments
The command LI (Linear Interpolation Distance) x 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 CS (Clear Sequence) 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 (Abort) . The ST (Stop)
command causes a decelerated stop. The command AB causes an instantaneous stop and aborts the
program, and the command AB1 aborts the motion only.
The LE (Linear Interpolation End) 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 SMC–4000 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.
The instruction _CS returns the number of the segment being processed. As the segments are processed,
_CS increases, starting at zero. This function allows the host computer to determine which segment is
being completed.
Additional Commands
The commands VS (Vector Speed) n, VA (Vector Acceleration) n, and VD (Vector Deceleration) n are
used to specify the vector speed, acceleration, and deceleration. The SMC–4000 computes the vector
speed based on the axes specified in the LM mode. For example, with LMXY, the vecor speed is
computed as:
VT (Vector Time Constant) is used to set the S-curve smoothing constant for coordinated moves. The
command AV (After Vector Distance) n is the ‘After Vector’ trippoint, which halts program execution
until the vector distance of n has been reached.
VS SPx
2
SPy
2
+ =