Galil Motion Control DMC-18 2 Series, Руководство пользователя

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74 ● Chapter 6 Programming Motion DMC-18x2
Specifying Vector Speed for Each Segment
The instruction VS has an immediate effect and, therefore, must be given at the required time. In some
applications, such as CNC, it is necessary to attach various speeds to different motion segments. This
can be done with two functions: < n and > m
For example: LI x,y,z,w < n >m
The first command, < n, is equivalent to commanding VSn at the start of the given segment and will
cause an acceleration toward the new commanded speed, subject to the other constraints.
The second function, > m, requires the vector speed to reach the value m at the end of the segment.
Note that the function > m may start the deceleration within the given segment or during previous
segments, as needed to meet the final speed requirement, under the given values of VA and VD.
Note, however, that the controller works with one > m command at a time. As a consequence, one
function may be masked by another. For example, if the function >100000 is followed by >5000, and
the distance for deceleration is not sufficient, the second condition will not be met. The controller will
attempt to lower the speed to 5000.
As an example, consider the following program.
#ALT Label for alternative program
DP 0,0 Define Position of X and Y axis to be 0
LMXY Define linear mode between X and Y axes.
LI 4000,0 <4000 >1000 Specify first linear segment with a vector speed of 4000 and end speed 1000
LI 1000,1000 < 4000 >1000 Specify second linear segment with a vector speed of 4000 and end speed 1000
LI 0,5000 < 4000 >1000 Specify third linear segment with a vector speed of 4000 and end speed 1000
LE End linear segments
BGS Begin motion sequence
EN Program end
Changing Feedrate:
The command VR n allows the feedrate, VS, to be scaled between 0 and 10 with a resolution of .0001.
This command takes effect immediately and causes VS to be scaled. VR also applies when the vector
speed is specified with the ‘<’ operator. This is a useful feature for feedrate override. VR does not
ratio the accelerations. For example, VR .5 results in the specification VS 2000 to be divided in half.
Command Summary - Linear Interpolation
COMMAND DESCRIPTION
LM xyzw Specify axes for linear interpolation
LM? Returns number of available spaces for linear segments in DMC-18x2 sequence buffer.
Zero means buffer full. 511 means buffer empty.
LI x,y,z,w < n Specify incremental distances relative to current position, and assign vector speed n.
VS n Specify vector speed
VA n Specify vector acceleration
VD n Specify vector deceleration
VR n Specify the vector speed ratio
BGS or BGT Begin Linear Sequence (on S or T coordinate system)
CS Clear sequence
LE Linear End- Required at end of LI command sequence
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