Rockwell-automation 1771-QA Stepper Positioning Assembly User Manual Manual do Utilizador descarregar pdf (Página 67)

3–45Programming and Operation

Publication 1771-UM002A–EN–P – May 2000

The following three examples show how this equation can be used.

Example Problem 1: Single-step mode or independent mode.

For the next move of a move profile, the change in move position

from beginning to end (DELPOS) must be 26k pulses. Determine

the maximum allowable final rate (FR) when using equal ramp and

decel times of 4 seconds.

The parameters of the equation (IR, FR, RT and DELPOS) and a

sketch of the move are shown in Figure 3.20.

Figure 3.20

Single Step or Independent Mode

Rate

RT DT

DEL POS

Start

Position

Final

Position

10530

Position

20 ms

Solution

Write down the known facts.

1. RT = DT = 4 seconds

DELPOS = 26k pulses

IR = 0 (The initial rate of a move in the single step or

independent mode is zero by definition.)

Find FR, the maximum final rate.

4(FR + 0)

+ FR

+ 0.02

26k

Choose a value for FR, say 10k pulses per second.

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Rockwell-automation 1771-QA Stepper Positioning Assembly User Manual Manual do Utilizador Página 67