Reference Manual

PMAC 2 Software Reference
76 PMAC I-Variable Specifiation
Motor Movement I-Variables
Ix20 Motor x Jog/Home Acceleration Time
Range
0 .. 8,388,607
Units
msec
Default
0 (so Ix21 controls)
Remarks
Ix20 establishes the time spent in acceleration in a jogging, homing, or programmed
RAPID-mode move (starting, stopping, and changing speeds). However, if Ix21
(jog/home S-curve time) is greater than half this parameter, the total time spent in
acceleration will be 2 times Ix21. Therefore, if Ix20 is set to 0, Ix21 alone controls the
acceleration time in “pure” S-curve form. In addition, if the maximum acceleration rate set
by these times exceeds what is permitted for the motor (Ix19), the time will be increased so
that Ix19 is not exceeded.
Note:
Do not set both Ix20 and Ix21 to 0 simultaneously, even if you are
relying on Ix19 to limit your acceleration, or a division-by-zero
error will occur in the jog move calculations, possibly resulting in
erratic motion.
A change in this parameter will not take effect until the next move command. For
instance, if you wanted a different deceleration time from acceleration time in a jog move,
you would specify the acceleration time, command the jog, change the deceleration time,
then command the jog move again (e.g. J), or at least the end of the jog (J).
See Also
I-variables I50, Ix16, Ix19, Ix21, Ix22, Ix23, Ix87, Ix88
Jogging and Homing Moves (Basic Motor Moves)
RAPID-mode moves (Writing a Motion Program)
On-line commands HM, J+, J-, J=, J^, J:, J/
Motion program command HOME, RAPID
Ix21 Motor x Jog/Home S-Curve Time
Range
0 .. 8,388,607
Units
msec
Default
50
Remarks
Ix21 establishes the time spent in each half of the S for S-curve acceleration in a jogging,
homing, or RAPID-mode move (starting, stopping, and changing speeds). If this
parameter is more than half of Ix20, the total acceleration time will be two times Ix21, and
the acceleration time will be “pure” S-curve (no constant acceleration portion). If the
maximum acceleration rate set by Ix20 and Ix21 exceeds what is permitted for the motor
(Ix19), the time will be increased so that Ix19 is not exceeded.
Note:
Do not set both Ix20 and Ix21 to 0 simultaneously, even if you are
relying on Ix19 to limit your acceleration, or a division-by-zero
error will occur in the jog move calculations, possibly resulting in
erratic motion.