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 .5 results in the specification VS 2000 to be
divided by two
Compensating for Differences in Encoder Resolution:
By default, the DMC-1600 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 Chapter 11, Command
Summary.
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-1600 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.
Example:
Assume an XY table with the Z-axis controlling a knife. The Z-axis has a 2000 quad counts/rev
encoder and has been initialized after power-up to point the knife in the +Y direction. A 180
°
circular cut is desired, with a radius of 3000, center at the origin and a starting point at (3000,0).
The motion is CCW, ending at (-3000,0). Note that the 0
°
position in the XY plane is in the +X
direction. This corresponds to the position -500 in the Z-axis, and defines the offset. The motion
has two parts. First, X,Y and Z are driven to the starting point, and later, the cut is performed.
Assume that the knife is engaged with output bit 0.
#EXAMPLE Example
program
VM XYZ
XY coordinate with Z as tangent
TN 2000/360,-500
2000/360 counts/degree, position -500 is 0 degrees in XY plane
CR 3000,0,180
3000 count radius, start at 0 and go to 180 CCW
DMC-1600
Chapter 6 Programming Motion
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