ABB TB82PH Instrucciones de operaciones descargar pdf (Pagina 22)

I-E67-TB82FF-2A February 13, 2002

The transmitter provides support for all Virtual

Communication Relations (VCR). These

relationships represent the rules for communication

between objects connected on the fieldbus. Below is

a brief description of these communication

relationships.

Client/Server VCR Type

This type of communication is used for configuration

and maintenance purpose and includes functions

such as setting parameter access, changing

parameter values, alarm acknowledgement,

uploading and downloading parameter values. In

other words, this type of communication is used for

queued, unscheduled, user initiated, one to one

communication between devices on the fieldbus. The

LAS is responsible for distributing and assigning a

Pass Token (PT) to the devices on the fieldbus. The

device that has the token can send a request to

another device. The requesting device is called the

Client and the device that receives the request is

called the Server.

Report/Distribution VCR Type

This type of communication is typically used by

fieldbus devices to send alarm notifications or trend

reports to a Master Device. This type of

communication is a queued, unscheduled, user

initiated communication between one and many other

devices.

Publisher/Subscriber VCR Type

This type of communication is used for Process

Control purposes. When a device has been

scheduled to send data, this data is Published or

broadcasted onto the fieldbus. Devices that wish to

receive this Published data are called Subscribers.

This type of communication is a scheduled and cyclic

exchange of data and is used to publish function

block inputs and outputs such as process variable

and primary output information onto the fieldbus.

Refer to the following figure for a summary of the VCR Types.

FIELDBUS ACCESS SUBLAYER SERVICES

Client/Server

VCR Type

Report/Distribution

VCR Type

Publisher/Subscriber

VCR Type

Used for

Operator Messages

• Mode Changes

• Tuning Changes

• Upload/Download

• Alarm Management

• Access Display Views

• Remote Diagnostics

Used for Event

Notification and Trend Reports

• Send Process alarms to operator

consoles

• Send trend report for data

histories

Used for

Publishing Data

• Send transmitter PV and SV

data to control blocks and

operator consoles

DATA LINK LAYER SERVICES

1 2 ... 17 18 19 20 21 22 23 24 25 26 27 ... 59 60

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ABB TB82PH Instrucciones de operaciones Pagina 22

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