Vega VEGAPULS 43 Profibus PA Bedienungsanleitung PDF herunterladen (Seite 7)

VEGAPULS 43 – Profibus PA 7

Product description

1.3 Profibus output signal

PROPRO

PROPRO

PROcess

FIFI

FIFI

FIeld

BUSBUS

BUSBUS

BUS (PROFIBUS) is the re-

sult of a joint project of thirteen companies

and five universities. The companies Bosch,

Klöckner-Möller and Siemens played a deci-

sive role. The specifications of the bus are

described in the protocol layers 1, 2 and 7 of

the ISO/OSI reference model and are avail-

able from the PNO (Profibus user organisa-

tion). Since layers 3 … 5 have not yet been

developed as a standard, Profibus still has a

lot of far-reaching potential.

Today approx. 600 companies make use of

Profibus technology and belong to the PNO.

Profibus

FMSFMS

FMSFMS

FMS stands for Fieldbus Messaging

Specification, Profibus

DPDP

DPDP

DP for Decentralised

Periphery and Profibus

PP

PP

P

AA

AA

A for Process Auto-

mation.

As a process automation bus, Profibus PA

also enables power supply over the bus. Up

to 32 sensors can be operated on a shielded

two-wire cable that carries both power sup-

ply and measurement signal. In Ex areas, up

to ten sensors can be connected from the PA

level to one two-wire cable (EEx ia).

Bus structure

The Profibus DP and PA network consists of

up to 126 master and slave participants.

Data are always exchanged from point to

point, with the data traffic being exclusively

controlled and checked by master devices.

Communication is carried out acc. to the

Token-Passing procedure. This means that

the master holding the Token can contact the

slaves, give instructions, enquire data and

cause the slaves to receive and transmit

data. After the work is done or after a prede-

termined time interval, the Token is passed

on by the master to the next master.

Master-Class 1

is the actual automation system, i.e. the proc-

ess control computer or the PLC that en-

quires and processes all measured values.

Master-Class 2

One or several Master-Class 2 can operate in

a Profibus network. As a rule, Master-Class 2

devices are engineering, adjustment or visu-

alisation stations. The VEGA adjustment soft-

ware VVO (VEGA Visual Operating) operates

as Master-Class 2 participant on the DP bus

and can work on an engineering PC, on an

adjustment PC or on the process control

computer and can access any VEGA sensor

on the PA level.

Instrument master file

A so-called GSD file is delivered with every

VEGAPULS Profibus sensor. This file is re-

quired to integrate the sensor into the bus

system. The GSD (instrument master file)

contains, beside the sensor name and the

manufacturer, the sensor-specific communi-

cation parameters which are necessary for a

stable integration of the sensor in the bus.

Load the GSD file belonging to the sensor

into your bus configuration program. If the

GSD file is not available, it can be

downloaded from the VEGA homepage: http:/

/www.vega.com.

Do not confuse the GSD file with the EDD

(Electronic Device Description), a file which is

necessary for the PDM environment (this can

be also found on the VEGA homepage).

1 2 3 4 5 6 7 8 9 10 11 12 ... 59 60

Kommentare zu diesen Handbüchern

Keine Kommentare