Reference Manual

PMAC 2 Software Reference
30 PMAC I-Variable Specifiation
I12 Jog-to-Position Calculation Time
Range
1 .. 8,388,607
Units
msec
Default
10
Remarks
I12 controls how much time is allotted to calculate an on-line jog or homing-search move
or a motion program RAPID move, including the “post-trigger” portions of triggered
moves (homing search, move until trigger). If a motor is currently moving, it will continue
on its present course during that time. If it is currently sitting still, it will continue to sit for
this time.
This parameter should rarely need to be changed from the default. It should not be set to 0
for any reason, or PMAC will not be able to perform any of these types of moves. The
minimum practical value for this parameter is 2 or 3.
See Also
I-variables I11, I13
Program command RAPID
On-line commands J=, J={constant}, J/, J^{constant}, J:{constant}
I13 Programmed Move Segmentation Time
Range
0 .. 8,388,607
Units
msec
Default
0
Remarks
I13 controls how PMAC performs its interpolation calculations for LINEAR and CIRCLE
mode moves. If I13 is set to 0, PMAC interpolates directly from the starting point of the
programmed move to the ending point. This mode creates satisfactory linear interpolation
in Cartesian systems, but cannot generate circular paths.
When I13 is set greater than 0, this puts PMAC into a mode (“segmentation mode”) where
all LINEAR and CIRCLE moves are done as a continuous cubic spline in which the move
segments are of the time length specified by the parameter in this variable (this is not the
same thing as SPLINE mode moves). This mode is required for applications using
CIRCLE mode moves.
Segmentation mode (I13 greater than 0) is required to support any of the following PMAC
features:
• Circular interpolation
• Cutter radius compensation
• / Program stop command
• \ Program hold command
• Rotary buffer blend on-the-fly
• Special multiple-move lookahead (Option 6L firmware)
If none of these features is required, it is usually best to leave I13 at 0, for more efficient
computation.
Typical values of I13 for segmentation mode are 5 to 10 msec. The smaller the value, the
tighter the fit to the true curve, but the more computation is required for the moves, and the
less is available for background tasks. If I13 is set too low, PMAC will not be able to do
all of its move calculations in the time allotted, and it will stop the motion program with a
run-time error.