Rockwell-automation 1771-QA Stepper Positioning Assembly User Manual Manual do Utilizador descarregar pdf (Página 61)

3–39Programming and Operation

Publication 1771-UM002A–EN–P – May 2000

Example Problem 1

A PLC-2/30 programmable controller is controlling 4 I/O racks in

remote configuration (Figure 3.18). A 3-axis stepper positioning

assembly is located in each rack. Assume that the stepper controller

module is operating in default mode and that the ladder diagram

program contains 4K words (K 1024). There are no other block

transfer modules in the system.

Figure 3.18

Remote System Example

PLC–2/30

1772–SD

1771–AS

1771–QA

Rack No. 1

1771–AS

1771–QA

Rack No. 2

1771–AS

1771–QA

Rack No. 3

1771–AS

1771–QA

Rack No. 4

10535

10,000’ System

What is the worst case time between two consecutive write block

transfers for this system when a 64 word moveset block is

transferred to the stepper positioning assemblies and a ten word

status block is returned to the PC processor?

Solution

1. Write down the known facts.

Program length = 4K words

Number of chassis = 4 rack numbers

Number of default block transfer words = 64 words (write),

10 words (read)

2. Calculate the system values.

1 2 ... 56 57 58 59 60 61 62 63 64 65 66 ... 131 132

Sem comentários

Rockwell-automation 1771-QA Stepper Positioning Assembly User Manual Manual do Utilizador Página 61