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PMAC 2 Software Reference

352 PMAC Program Command Specification

TA{data}

Function

Set Acceleration Time

Type

Motion program (PROG and ROT)

Syntax

TA{data}

where:

• {data} is a constant or expression representing the acceleration time in

milliseconds

Remarks

This statement specifies the commanded acceleration time between blended moves

(LINEAR and CIRCLE mode), and from and to a stop for these moves. In PVT and

SPLINE1 mode moves, which are generally continually accelerating and decelerating, it

specifies the actual move segment time. The units are milliseconds. PMAC will round

the specified value to the nearest integer number of milliseconds when executing this

command (no rounding is done in storing the value in the buffer).

Note:

Make sure the specified acceleration time (TA or 2*TS) is greater than

zero, even if you are planning to rely on the maximum acceleration rate

parameters (Ix17). A specified acceleration time of zero will cause a

divide-by-zero error. The minimum specified time should be TA1 TS0.

If the specified S-curve time (from TS, or Ix88) is greater than half the TA time, the time

used for the acceleration for 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 TA controls the move time, it must be greater than the I13 time and the I8

period.

Note:

The acceleration time will be extended automatically when any motor in

the coordinate system is asked to exceed its maximum acceleration rate

(Ix17) for a programmed LINEAR mode move with I13=0 (no move

segmentation).

A move executed in a program before any TA statement will use the default acceleration

time specified by coordinate system I-variable Ix87.

In executing the TA command, PMAC rounds the specified value to the nearest integer

number of milliseconds (there is no rounding done when storing the command in the

buffer).

Example

TA100

TA(P20)

TA(45.3+SQRT(Q10))