About fieldbus, 1 outline, 2 internal structure of yta – Yokogawa Wireless Temperature Transmitter YTA510 User Manual

Page 9: 1 system/network management vfd, 2 function block vfd, 3 logical structure of each block, About fieldbus -1, Outline -1, Internal structure of yta -1 3.2.1, System/network management vfd -1

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<3. About Fieldbus>

3-1

IM 01C50T02-01E

3. About Fieldbus

3.1 Outline

Fieldbus is a bi-directional digital communication

protocol for field devices, which offers an

advancement in implementation technologies for

process control systems and is widely employed by

numerous field devices.
YTA Series Fieldbus communication type employs

the specification standardized by The Fieldbus

Foundation, and provides interoperability between

Yokogawa devices and those produced by other

manufacturers. Fieldbus comes with software

consisting of four AI function blocks and four DI

function blocks, providing the means to implement

a flexible instrumentation system.
For information on other features, engineering,

design, construction work, startup and maintenance

of Fieldbus, refer to “Fieldbus Technical Information”

(TI 38K3A01-01E).

3.2 Internal Structure of YTA

The YTA contains two virtual field devices (VFD)

that share the following functions.

3.2.1 System/network Management VFD

• Sets node addresses and Phisical Device tags

(PD Tag) necessary for communication.

• Controls the execution of function blocks.

• Manages operation parameters and

communication resources (Virtual

Communication Relationship: VCR).

3.2.2 Function Block VFD

(1) Resource block (RS)

• Manages the status of YTA hardware.

• Automatically informs the host of any detected

faults or other problems.

(2) Transducer block (TR)

• Accepts temperature input from sensors and

transfers to AI function block.

• Operates limit swtich calculation and transfers

to DI function block.

(3) AI function block

• Conditions raw data from the Transducer block.

• Outputs temperature signal.

• Carries out scaling, damping and square root

extraction.

(4) DI function block

• Limit switch for temperature.

• Accepts the discrete signal from Transducer

block and Outputs the discrete signal to show if

the temperature exceeds the preset limit.

(5) PID function block

• Performs the PID control computation based on

the deviation of the measured value from the

setpoint.

3.3 Logical Structure of Each

Block

F0301.ai

YTA

Fieldbus

System/network management VFD

Function block VFD

Link Master (option)

PD Tag

Sensor

input

Resource block

Block tag

Parameters

PID function

block (option)

Communication

parameters

VCR

Node address

Function block

execution schedule

DI function

block

Output

AI function

block

Block tag

OUT

Parameters

Transducer

block

Block tag

Parameters

Temperature Sensor

Figure 3.1

Logical Structure of Each Block

Setting of various parameters, node addresses,

and PD Tags shown in Figure 3.1 is required before

starting operation.

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