Reference Manual
PMAC 2 Software Reference 
PMAC I-Variable Specification  73 
Ix15  Motor x Deceleration Rate on Position Limit or Abort 
Range 
positive floating point 
Units 
Counts/msec
2
Default 
0.25 
Remarks 
WARNING: 
Do not set this parameter to zero, or the motor will continue 
indefinitely after an abort or limit. 
Ix15 sets the rate of deceleration that Motor x will use if it exceeds a hardware or software 
limit, or has its motion aborted by command (A or <CONTROL-A). This value should 
usually be set to a value near the maximum physical capability of the motor. It is not a 
good idea to set this value past the capability of the motor, because doing so increases the 
likelihood of exceeding the following error limit, which stops the braking action, and could 
allow the axis to coast into a hard stop. 
Example 
Suppose your motor had 125 encoder lines (500 counts) per millimeter, and you wished it 
to decelerate at 4000 mm/sec
2
. You would set Ix15 to 4000 mm/sec
2
 *500 cts/mm * 
sec
2
/1,000,000 msec
2
 = 2 cts/msec
2
. 
See Also 
On-line commands A, <CONTROL-A> 
Hardware Overtravel Limits, Software Overtravel Limits (Making Your Application Safe) 
Ix16  Motor x Maximum Permitted Motor Program 
Range 
positive floating point 
Units 
Counts/msec 
Default 
32.0 
Remarks 
Ix16 sets a limit to the allowed velocity for LINEAR mode programmed moves for Motor 
x, provided I13 equals zero (no move segmentation). If a blended move command in a 
motion program requests a higher velocity of this motor, all motors in the coordinate 
system are slowed down proportionately so that Motor x will not exceed this parameter, 
yet the path will not be changed. This limit does not affect transition-point, circular, or 
splined moves. The calculation does not take into account any feedrate override value 
other than 100). 
Note: 
If PMAC’s circular interpolation function is used at all, then I13 
must be greater than zero, and Ix16 will not be active as a velocity 
limit. 
This parameter also sets the speed of a programmed RAPID mode move for the motor, 
provided that variable I50 is set to 1 (if I50 is set to 0, jog speed parameter Ix22 is used 
instead). This happens regardless of the setting of I13. 
With the Option 6L special lookahead firmware, Ix16 sets the limit for velocity of 
LINEAR and CIRCLE mode moves with segmentation active (I13 > 0). 
See Also 
I-variables I13, I50, Ix17, Ix22 
Velocity Limits (Making Your Application Safe) 
LINEAR, RAPID-mode moves (Writing a Motion Program) 










