User`s manual

5.0 - Motion Programs
Page - 48
PMAC looks two moves ahead of actual move execution to perform its acceleration limit, and can recalculate these
two moves to keep the accelerations under the Ix17 limit. However, there are cases where more than two moves, some
much more than two, would have to be recalculated in order to keep the accelerations under the limit. In these cases,
PMAC will limit the accelerations as much as it can, but because the earlier moves have already been executed, they
cannot be undone, and therefore the acceleration limit will be exceeded.
3) When performing a blended move that involve a change of direction, the end point might no be reached.
Example:
TA100
TM250
X10 ; This would reach only to position =
9
250 . 4
10 . 100
10 =−
X-10
In order to reach the desired position, since the move involves a change in direction and stop, simply place a DWELL0
command between moves. This command will disable blending for that particular move:
TA100
TM250
X10
DWELL0
X-10
4) Since the value of TA determines the minimum time in which a programmed move could be executed, it could limit
the maximum move velocity and therefore the programmed feedrate might not be reached. This is seen in “triangular”
velocity profile moves types, especially when a sequence of short distance moves is programmed.
Example:
close
delete gather
undefine all
&1
#1->2000X
I190=1000
OPEN PROG 1 CLEAR
LINEAR ; Linear mode
INC ; Incremental mode
TA100 ; Acceleration time is 100 msec, TA
1
TS0 ; No S-curve component
F40 ; Feedrate is 40 length_units / second
X3 ;
cmse 75
40
3000
40
I190 . 3
TM ===
CLOSE
TM . 4
ion)(end_posit .TA
: toequal