Yokogawa YVP110 - Manual (Page 49)

<8. About Fieldbus>
8-1
IM 21B04C01-01E
8. About Fieldbus
8.1 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.
YVP110 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 AO function
block, two DI function blocks OS function block, IS
function block, AR function block and optional PID
function block, 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).
8.2 Internal Structure of YVP110
The YVP110 contains two virtual field devices
(VFD) that share the following functions.
8.2.1 System/network Management VFD
• Sets node addresses and Physical Device tags
(PD Tag) necessary for communication.
• Controls the execution of function blocks.
• Manages operation parameters and
communication resources (Virtual
Communication Relationship: VCR).
8.2.2 Function Block VFD
(1) Resource block
Manages the information common to each FB
VFD in YVP110.
(2) Transducer block
Located between Hardware I/O(actuator,
sensor) and AO/DI function blocks, pass the
control signal from AO function block to I/P
module to control the valve position.
(3) AO function block
• Accepts a control signal from an upstream
block and pass the signal to Transducer
block.
• Accept a valve position signal from
Transducer block and feedback it to an
upstream block.
(4) DI function block
Receives the discrete signal from Transcducer
blcok and output them.
(5) PID function block(optional)
Offers PID control function.
8.3 Logical Structure of Each
Block
AR Function
IS Function
OS Function
F0801.ai
YVP110
PID Function
DI Function
Function Block VFD
Resource block
DI Function
AO Function
block
Block tag
OUT
Parameters
Transducer
block
Block tag
Parameters
PD tag (Device tag) Communication
parameters
VCR
Node address
Position feedback signal
Position Sensor
I/P
Module
Control output
Output to other blocks
Input from other blocks
System/network management VFD
Function block
execution schedule
Block tag
Parameters
Figure 8.1 Logical Structure of Each Block
Setting of various parameters, node addresses,
and PD Tags shown in Figure 8.1 is required before
starting operation.
8.4 System Configuration
The following instruments are required for use with
Fieldbus devices: