ABB TB82PH Betriebsanleitung PDF herunterladen (Seite 21)

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

Transmitter Identification (FF.ID) State

There are several ways to identify a transmitter in the

network, and more precisely, three different

addressing levels are used to characterize a

FOUNDATION Fieldbus device.

The most important is the Device Identifier (i.e.,

DEV_ID). This identifier is a string of 32 characters

and provides a unique FOUNDATION Fieldbus device

address by incorporating a manufacturer code, device

type code, device type identification, and sensor serial

number.

Since this identifier must have a unique value, the

FF.ID state is password protected. To access to this

screen, a user must contact the factory for further

instructions.

Damping State

The Damping State applies a lag function on the

process input. The Damping State values affect

Process and Secondary Value 4 (Function Generator)

transmitted values. Application of the FV_VALUE in

the AI blocks will apply an additional damping on the

mapped variable. To adjust the Damping State, the

password 367 must be entered when requested by

the transmitter.

TRANSMITTER'S FIELDBUS FUNCTIONALITY

The Data Link Layer of Fieldbus FOUNDATION

Protocol defines three types of device:

• Basic device

• Link Master

• Bridge

Basic

Device

Backup

Link

Active

Scheduler

Master

Link

Active

Scheduler

Basic

Device

Basic

Device

LAS

Fieldbus

The Link Master device is typically the Link Active

Scheduler (LAS); thus, it is responsible for organizing

the activity/communication on the fieldbus. Basic

Devices do not have the capability to become the

LAS. Bridges are used to interconnect individual

fieldbuses to create larger networks.

A Fieldbus may have multiple Link Masters. If the

primary LAS device fails, one of the other Link

Masters will assume LAS responsibilities. In this

manner, the operation of the fieldbus link will be

maintained. The TB82EC Foundation Fieldbus

Transmitter does not have the capability of being

a backup LAS device. Below is a complete list of

the transmitter fieldbus functionality:

• Standard Resource Block: This block contains

the description of the transmitter characteristics.

• Standard Analog Input Function Block: Two

Analog Input Function Blocks are available for

control loop operations.

• Enhanced Transducer Block with calibration

capability: This block contains configuration

parameters, calibration functions, and diagnostic

data.

The transmitter allows different types of

communication services as described by the Fieldbus

Message Specification (FMS). These FMS services

permit a User Application to send serial messages to

each device across the fieldbus network using a

standard message format. FMS describes the

communication services, the format of the message,

and the protocol behaviors required to build

messages for the User Application. A pictorial

illustration of this methodology is shown below.

FMS

DLL

PHY

FAS

FMS

DLL

PHY

FAS

User

Application

User

Application

Fieldbus

Device

Fieldbus

Device

Communication

Services

The FMS Services supported by the transmitter are

listed below:

• Initiate - used to establish the initial

communication.

• Abort - used to release the communication.

• Status - used to read a device status.

• Identify - used to read vendor, type and version

information.

• Read variable - used to read a variable.

• Write variable - used to write a variable.

• Get Object Dictionary - used to read an Object

Dictionary.

1 2 ... 16 17 18 19 20 21 22 23 24 25 26 ... 59 60

Kommentare zu diesen Handbüchern

Keine Kommentare

ABB TB82PH Betriebsanleitung Seite 21

Kommentare zu diesen Handbüchern