Vega VEGACOM 557 Modbus protocol Bedienungsanleitung PDF herunterladen (Seite 32)

32 VEGACOM 557 Modbus

4.4 Image of the contact outputs on

LOGBUS

Beside the previously described measured

values, it is also possible to transmit the

switching status of VEGA processing system

VEGALOG 571 through VEGACOM 557.

These are:

- status of the contact output of the AR cards

(relay contacts)

- status of the contact outputs of the AT

cards (transistor outputs)

In contrast to the image of measured values,

the image of the switching status is made "bit

orientated“. In the standard, these status bits

are also called “register bits”. The address-

ing of the register bits for Modbus systems is

therefore made "bit orientated“. In VEGACOM

557, a switching status is represented by a

register bit, whereby all available information

of a VEGALOG output card of type AR or AT

is saved within a related block of 16 register

bits. The storage of a 16 register bit block

within VEGACOM 557 results from the mod-

ule position in VEGALOG 571.

The addressing by the guidance system is

made either via existing library enquiries of a

processing system (e.g. Modicon) or by direct

generation of the Modbus telegrams.

Please keep in mind that the number of regis-

ter bits to be enquired per telegram should

always be divisible by 8.

For enquiry of the switching status, the func-

tion codes 01 or 02 can be used on VEGA-

COM 557 for input and output status.

Note:

When addressing register bits, all addresses

between 0 and 65 535 can be used with

VEGACOM 557. For accessing the intermedi-

ate storage area, VEGACOM 557 uses gen-

erally only the last 3 digits of the address.

This means:

Register Register Register

address in address on address in

Modicon Modbus VEGACOM

557

00 001 00 000 000

10 017 10 016 016

04 001 04 000 000

14 017 14 016 016

Image of switching status in VEGACOM 557 on VEGA-

LOG 571

on

PC

VEGALOG

571

!

Output status of output card on

module #1

Output status of output

card on module #32

Data image in VEGACOM 557

1 2 ... 27 28 29 30 31 32 33 34 35 36 37 ... 67 68

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