Galil Motion Control DMC-42 0 Series, User Manual

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Additional commands
The commands VS n, VA n and VD n are used for specifying the vector speed, acceleration, and deceleration.
IT is the s curve smoothing constant used with coordinated motion.
Specifying Vector Speed for Each Segment:
The vector speed may be specified by the immediate command VS. It can also be attached to a motion segment
with the instructions
VP x,y < n >m
CR r, ɵ,δ< 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 speeds, subjects 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, but will reach that at a different point.
Changing Feed Rate:
The command VR n allows the feed rate, VS, to be scaled between 0 and 10 with a resolution of .0001. This
command takes effect immediately and causes VS scaled. VR also applies when the vector speed is specified with
the ‘<’ operator. This is a useful feature for feed rate override. VR does not ratio the accelerations. For example,
VR 0.5 results in the specification VS 2000 to be divided by two.
Compensating for Differences in Encoder Resolution:
By default, the DMC-42x0 uses a scale factor of 1:1 for the encoder resolution when used in vector mode. If this is
not the case, the command, ES can be used to scale the encoder counts. The ES command accepts two arguments
which represent the number of counts for the two encoders used for vector motion. The smaller ratio of the two
numbers will be multiplied by the higher resolution encoder. For more information, see ES command in the
Command Reference.
Trippoints:
The AV n command is the After Vector trippoint, which waits for the vector relative distance of n to occur before
executing the next command in a program.
Tangent Motion:
Several applications, such as cutting, require a third axis (i.e. a knife blade), to remain tangent to the coordinated
motion path. To handle these applications, the DMC-42x0 allows one axis to be specified as the tangent axis. The
VM command provides parameter specifications for describing the coordinated axes and the tangent axis.
VM m,n,p m,n specifies coordinated axes p specifies tangent axis such as X,Y,Z,W p=N
turns off tangent axis
Before the tangent mode can operate, it is necessary to assign an axis via the VM command and define its offset
and scale factor via the TN m,n command. m defines the scale factor in counts/degree and n defines the tangent
position that equals zero degrees in the coordinated motion plane. The operand _TN can be used to return the
initial position of the tangent axis.
Chapter 6 Programming Motion ▫ 68 DMC-42x0 User Manual