Reference Manual

Turbo PMAC/PMAC2 Software Reference
Turbo PMAC Global I-Variables 188
On-line commands FRAX, NOFRAX
Motion program commands F, FRAX, NOFRAX
Isx87 Coordinate System x Default Program Acceleration Time
Range: 0 - 8,388,607
Units: msec
Default: 0 (so Isx88 controls)
Isx87 sets the default time for commanded acceleration for programmed blended LINEAR and CIRCLE
mode moves in Coordinate System x. If global variable I42 is set to 1, it also sets the default time for
PVT and SPLINE mode moves. The first use of a TA statement in a program overrides this value.
Note:
Even though this parameter makes is possible not to specify acceleration time in
the motion program, use TA in the program and do not rely on this parameter,
unless keeping to a syntax standard that does not support this (e.g. RS-274 G-
Codes ). Specifying acceleration time in the program along with speed and move
modes makes it much easier for later debugging.
If the specified S-curve time (see Isx88, below) is greater than half the specified acceleration time, the
time used for commanded acceleration in blended moves will be twice the specified S-curve time.
The acceleration time is also the minimum time for a blended move; if the distance on a feedrate-
specified (F) move is so short that the calculated move time is less than the acceleration time, or the time
of a time-specified (TM) move is less than the acceleration time, the move will be done in the
acceleration time instead. This will slow down the move. If the acceleration time is 0 because both TA
and TS are set to 0, the minimum move time is 0.5 msec.
Note:
The acceleration time will be extended automatically when any motor in the
coordinate system is asked to exceed its maximum acceleration rate (Ixx17) for a
programmed LINEAR-mode move with Isx13=0 (no move segmentation).
When polled, Isx87 will report the value from the most recently executed TA command in that coordinate
system.
Isx88 Coordinate System x Default Program S-Curve Time
Range: 0 - 8,388,607
Units: msec
Default: 50
Isx88 sets the default time in each half of the S in S-curve acceleration for programmed blended LINEAR
and CIRCLE mode moves in coordinate system x. It does not affect SPLINE, PVT, or RAPID mode
moves. The first use of a TS statement in a program overrides this value.
Note:
Even though this parameter makes is possible not to specify acceleration time in
the motion program, use TS in the program and do not rely on this parameter,
unless keeping to a syntax standard that does not support this (e.g. RS-274 G-
Codes). Specifying acceleration time in the program along with speed and move
modes makes it much easier for later debugging.
If Isx88 is zero, the acceleration is constant throughout the Isx87 time and the velocity profile is
trapezoidal.