Rockwell-automation MPP Processor Moduile Uživatelský manuál stáhnout pdf (Strana 11)

MPP

October

200

5

–

Issue

6

11

Triguard

SC300E MPP Processor Module

THEORY OF OPERATION

SC300E system overview

A block

diagram

showing

the

signal

flow

between

the

main

functional

areas

of

the

MPP

is

shown

in

Figure

2

-

3 . External

communication

is

via

the

chassis

backplane

wiring

as

summarised

in

Figure

2

-

1

.

All

SC300E

input

and

output

modules

interface

to

three

isolated

I/O

communications

buses

(shown

collectively

as

the

Processor

-

I/O

Bus

in

Figure

2

-

1 ),

each

being

controlled

by

one

of

the

MPPs.

At

the

input

modules,

field

signals

are

filtered

and

then

split,

via

isolating

circuitry,

into

three

identical,

signal

processing

paths.

Each

path

is

controlled

by

a microcontroller

that

coordinates

signal

path

processing,

testing

and

signal

status

reporting

to

its

respective

M

PP,

via

one

of

the

I/O

communications

buses.

Each

of

the

MPPs

communicates

with

its

neighbours

via

read

only,

serial

communications

links

(Figure

2

-

4

).

Figure

2

-

4 Read

serial

communications

only

links

The

MPPs

synchronise

at

least

once

per

application

logic

execution

cycle,

and

each

reads

the

input,

output

and

diagnostic

status

of

its

neighbours.

Each

MPP

correlates

and

corrects

its

memory

image

of

the

current

state

of

the

system

using

a 2

-

oo

-

3 software

vote,

logging

any

discrepancies

found

in

a local

diagnostic

history

table.

Each

MPP

then

executes

its

programmed

application

logic

and

sets

its

respective

outputs,

via

the

I/O

communications

bus,

to

the

required

state.

1 2 ... 6 7 8 9 10 11 12 13 14 15 16 ... 24 25

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