Reference Manual

PMAC 2 Software Reference
PMAC I-Variable Specification 125
See Also
Time-Base Control (Synchronizing PMAC to External Events)
I-variables I10, Ix93, Ix95
On-line commands %{constant}, %
Ix95 Coordinate System x Feed Hold Slew Rate
Range
0 .. 8,388,607
Units
2
-
23
msec/servo cycle
Default
1644
Remarks
Ix95 controls the rate at which the axes of the coordinate system stop if a feed hold
command (H) is given, and the rate at which they start up again on a succeeding run
command (R or S). A feed hold command is equivalent to a %0 command except that it
uses Ix95 for its slew rate instead of Ix94. Having separate slew parameters for normal
time-base control and for feed hold commands allows both responsive ongoing time-base
control (Ix94 relatively high) and well-controlled holds (Ix95 relatively low).
Note:
The default Ix95 value of 1644, when used on a card set up with the
default servo cycle time of 442 µsec, provides a transition time
between %100 and %0 (feed hold) of one second.
See Also
Stop Commands (Making Your Application Safe)
Time-Base Control (Synchronizing PMAC to External Events)
I-variables I10, Ix93, Ix94
On-line commands H, <CONTROL-O>, R, <CONTROL-R>, S, <CONTROL-S>, %.
Ix96 Coordinate System x Circle Error Limit
Range
positive floating point
Units
User length units
Default
0 (function disabled)
Remarks
In a circular arc move, a move distance that is more than twice the specified radius will
cause a computation error because a proper path cannot be found. Sometimes, due to
round-off errors, a distance slightly larger than twice the radius is given (for a half-circle
move), and it is desired that this not create an error condition.
Ix96 allows the user to set an error limit on the amount the arc move distance is greater
than twice the specified radius. If the move distance is greater than 2R, but by less than
this limit, the move is done in a spiral fashion to the endpoint, and no error condition is
generated. If the distance error is greater than this limit, a run-time error will be generated,
and the program will stop. If this variable is set to 0 the error generation is disabled and
any move distance greater than 2R is done in a spiral fashion to the endpoint.
If the circular move is specified with an IJK center-vector instead of an R radius, Ix96 is
not used.
Example
Given the program segment
INC CIRCLE1 F2
X7.072 Y7.072 R5
technically no circular arc path can be found, because the distance is SQRT(7.072
2
+7.072
2
)
= 10.003, which is greater than twice the radius of 5. However as long as Ix96 is greater
than 0.003, PMAC will create a near-circular path to the end point.
See Also
Circular Blended Moves (Writing a Motion Program)
Program commands CIRCLE1, CIRCLE2, {axis}{data}{vector}{data}