IDC Technologies

INTRODUCTIONINTRODUCTION

Chapter 1Chapter 1

IDC Technologies

TopicsTopics

IntroductionModern Instrumentation and ControlOSI ModelProtocolsStandards

IDC Technologies

IntroductionIntroductionTransfer of Information From One Point to

AnotherTransmitter/Receiver/LinkSerial Links vs Parallel LinksDigital Data vs AnalogMutual Agreement

IDC Technologies

Historical BackgroundHistorical Background

Telegraph SystemMorse CodeBaudot Code

IDC Technologies

Three Themes Three Themes

Physical StandardsOpen Systems InterconnectionProtocols

IDC Technologies

StandardsStandards

EIA-232 Interface StandardEIA-485 Interface Standard

IDC Technologies

A Typical Serial Data A Typical Serial Data Communications LinkCommunications Link

RS-232 RS-232

Terminal Modem

Transmitted Data Received DataAnalog Signal

Modem Communication Link Terminal

DTE DCEDCE DTE

IDC Technologies

Modern InstrumentationModern Instrumentation Distributed Control System (DCS)

All Electronic tightly integrated system

Programmable Logic Controller (PLC) Came from Relay Equipment

SCADA System RTU’s and Master Station - radio links

Smart Instrumentation Intelligent Sensors on comms link Fieldbuses and Devicenets ( and HART)

IDC Technologies

Distributed Control System Distributed Control System (DCS)(DCS)

Based Around a Data HighwayModular Distributed & IntegratedEach Module Performs Specific Dedicated

Task“Good” on Analog ControlEasy Connection to PLC’s / supervisory

Computer Interfaces

IDC Technologies

PLCPLC Programmable Logic

Controller

Sequence Control and Interlocking

On/Off Inputs/outputs

Ladderlogic Type Programs

IDC Technologies

A Typical PLC SystemA Typical PLC System

IDC Technologies

SCADASCADA

Supervisory Control and Data Acquisition System

RTU’s to Master StationRadio Links /LandlinesAlso term used for SCADA Software

package eg Citect

IDC Technologies

Smart InstrumentationSmart InstrumentationMicroprocessor Based Instrument

Embedded Controllers

Data Communications CapabilityRS- 232, RS 485 or Fiber OpticAbility to Multi-drop With Other

Instruments on Same HighwayWave of the Future...Eg Fieldbus

IDC Technologies

OSI ModelOSI Model

Developed by the ISOUniversal Framework for Building A

Communications Systems 7 Layer Model3 Layer Model Very Common for IndustryMissing the 8th Layer

IDC Technologies

Representation of the OSI ModelRepresentation of the OSI Model

IDC Technologies

Standards Within A Standards Within A Communications SystemCommunications System

Code - Morse - Hex - ASCIIPhysical - 232 - 422 - 485 Protocol - Modbus, Profibus, Hart,

Foundation Fieldbus, EthernetOpen Systems Interconnection Model

IDC Technologies

ProtocolsProtocols Rules for Transmission of Data (Packets) Packet Can Include:

Sync Byte Destination Address Source Address Data Error Detection

Modbus - Profibus - Canbus - Ethernet - TCP/IP HDLC - DH+ - HART - DNP3 - Interbus - FTP

IDC Technologies

Basic Structure of an Basic Structure of an Information Frame DefinedInformation Frame Defined

SyncByte

DestinationAddress

SourceAddress

Data to beTransmitted

Error DetectionByte

SYNCHRONIZING BYTE Is Used To Synchronize The Receiver.

DESTINATION ADDRESS Is Where The Packet Is Going.

SOURCE ADDRESS Is Where The Packet Has Come From.

DATA Is The Information Contained In The Packet.

ERROR BYTE Is The Result Of The Error Correction Calculation.

IDC Technologies

Voltage StandardsVoltage StandardsEIA/RS-232 Interface Standard

Half / Full Duplex - Point to Point

EIA/RS-485 Interface StandardHalf Duplex - Multidrop

IDC Technologies

RS-232RS-232

IDC Technologies

Two Wire Multidrop RS-485Two Wire Multidrop RS-485

R

R

G

G

RX RX

TX TX

A A

B B

A A

B B

GWG GWG

Rt Rt

R

G

RX

TX

A

B

A

B

GWG

R

G

RX

TX

A

B

A

B

GWG

- Generator

- Receiver

- Circuit ground orcircuit common

- Protective ground orframe ground

- Green wire ground orpower system ground

G

R

GWG

Note: The RS-485 standard documentationleaves out the invertes for the receiver

1200M (4000 FT)

TERMINATION RESISTORS AT BOTH ENDS ONLY

IDC Technologies

Fiber Optic CableFiber Optic Cable

CoreLight Rays

Light Ray

Cladding

Multimode

Monomode

Sheath

IDC Technologies

Modbus Protocol Modbus Protocol StructureStructure

IDC Technologies

Modbus PlusModbus Plus

Builds on ModbusToken Passing and deterministicHigh Speed - minimum of 1Mbit/s

IDC Technologies

HART ProtocolHART Protocol4 - 20 ma 4 - 20 ma

CommunicationsCommunications

IDC Technologies

ASI BusASI Bus

Idiot Proof167kbps and fast for digitals31 slaves and 124 I/O points with 5ms

scan

IDC Technologies

The DeviceNet ModelThe DeviceNet Model

IDC Technologies

ProfibusProfibusTypical Architecture of Typical Architecture of

SystemSystem

IDC Technologies

Foundation FieldbusFoundation Fieldbus

Newest FieldbusH1 standard - 31.25kbit/sHSE - 100Mbit/sThree layers plus excellent User Layer

IDC Technologies

Ethernet 10BaseT Ethernet 10BaseT

MAC = Media Access Control

IDC Technologies

TCP/IPTCP/IP

Internet Protocol (IP)Transmission Control Protocol (TCP)Application Layer

Three Layer ModelDerived from Internet

IDC Technologies

Wireless CommunicationsWireless Communications

RadioTransmitter/Receiver

RadioTransmitter/Receiver

Modem Modem

Antenna AntennaRS-232

RS-232