IDC Technologies INTRODUCTION INTRODUCTION Chapter 1 Chapter 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
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
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
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
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 PlusModbus Plus
Builds on ModbusToken Passing and deterministicHigh Speed - minimum of 1Mbit/s
IDC Technologies
ASI BusASI Bus
Idiot Proof167kbps and fast for digitals31 slaves and 124 I/O points with 5ms
scan
IDC Technologies
Foundation FieldbusFoundation Fieldbus
Newest FieldbusH1 standard - 31.25kbit/sHSE - 100Mbit/sThree layers plus excellent User Layer
IDC Technologies
TCP/IPTCP/IP
Internet Protocol (IP)Transmission Control Protocol (TCP)Application Layer
Three Layer ModelDerived from Internet