Rockwell-automation MPP Processor Moduile Instrukcja Użytkownika Pobierz pdf (Strona 12)

12

MPP

October

200

5

–

Issue 6

Triguard

SC300E

Commanded

output

states

are

received

by

an

output

module’s

microcontrollers

which,

using

2

-

oo

-

3 hardware

voters,

set

the

outputs

to

the

field.

Any

discrepancy

between

a commanded

output

state

and

the

field

output

is

detected

by

the

microcontrollers

and

reported

to

the

appropriate

MPP

OFFLINE/STARTUP DIAGNOSTICS

When

a SC300E’s

MPPs

are

f

irst

powered

up,

the

following

diagnostic

routines

are

executed:

•

Initialisation

of

all

SRAM

•

Memory

configuration

and

size

checks

•

RTTS

and

application

logic

copied

to

SRAM

•

All

program

checksums

recalculated

and

checked

•

Configuration

and

checksums

of

neighbouring

MPPs

read

and

confirmed

•

Initialisation

of

synchronisation

registers

•

Synchronisation

registers

of

neighbouring

processors

read

A processor

will

then

pause,

waiting

for

the

other

two

MPPs

to

complete

their

startup

diagnostics.

At

powerup

a SC300E

system

must

have

three

healthy

MPPs,

otherwise

the

startup

diagnostics

will

prevent

execution

of

the

system

application

logic.

In

the

event

of

a processor

failing

a replacement

MPP

can

be

brought

online

using

a warm

start

command.

Warm

start

commands

can

be

issued

from

a TriBuild

workstation

or

by

use

of

an

application

logic

assigned

input.

A newly

installed

MPP

will

execute

its

startup

diagnostics,

monitor

the

running

MPP’s

synchronisation

registers

and

await

a warm

start

command.

At

this

point

checksums

wi

ll

be

confirmed

and

the

new

MPP

acquires

I/O

data

tables

from

its

neighbours

and

commences

execution

of

its

application

logic.

Online/continuous diagnostics

All

memory

reads

and

writes

are

automatically

checked

for

errors

by

the

MPPs'

error

checking

and

correcting

circuitry.

Single

memory

errors

are

detected

and

corrected,

all

multiple

errors

are flagged.

Software

Implemented

Fault

Tolerant

(SIFT)

votes

the

data

tables

between

the

MPPs

using

a

majority

vote

algorithm,

any

errors

being

logged

and

corrected

by

the

processors

during

their

'read

neighbour's

data'

cycle.

Corrected

memory

errors

are

logged

in

diagnostic

history

tables.

These

tables

can

be

accessed

by

application

logic

functions

and

be

used

to

generate

system

alarms.

If

multiple

errors

are

detect

ed

an

MPP

will

be

halted.

An

MPP’s

I/O

hot

repair

task

regularly

scans

all

1 2 ... 7 8 9 10 11 12 13 14 15 16 17 ... 24 25

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