Troubleshooting of SCADA and Data Acquisition Systems by Steve Mackay Dean of Engineering

Transcription

1 Troubleshooting of SCD and Data cquisition Systems by Steve Mackay Dean of Engineering Topics ackground to SCD Simple SCD & Data cquisition System Typical SCD Communication Structures Troubleshooting Techniques for SCD 1

2 EIT Micro-Course Series Every two weeks we present a 35 to 45 minute interactive course Practical, useful with Q & throughout PID loop Tuning / rc Flash Protection, Functional Safety, Troubleshooting conveyors presented so far Upcoming: Electrical Troubleshooting and much much more.. Go to You get the recording and slides ackground to SCD

3 SCD Supervisory Control nd Data cquisition SCD is not just Software or Hardware ut a complete control system including communications systems SCD Supervisory Control and Data cquisition 3

4 Remote Terminal Unit The complete assembly of equipment at an end point of the control system in the field, factory or industrial site. This can be a Programmable Logic Controller (PLC). Typical SCD System 4

5 Local rea Networks High speed access Ethernet Industrial Ethernet SCD Systems Software 10 5

6 Components of a SCD System Display Server #1 Display Server # Printer I/O Database RS-3 Trend Server Task Report Server Task Input / Output Server Task Radio Modem Radio Modem In Out In Out Instrumentation & Control nalog Digital 11 Key Features User Interface Graphics Displays larms Trends RTU (and PLC) Interface Scalability ccess to data Database Networking Fault Tolerance and Redundancy Client/Server distributed processing 1 6

7 SCD Software Package Centralized Central Control Room Distance etween RTU s and Control Room Distributed De-Centralized Control Multiple Operators Proprietary Produced by a single company Open Standard Interoperability 13 Client Server for SCD Systems Trends larms I/O Report Tasks Display Task Trends larms Reports Display Database Databases I/O Database Server Node Display Node Display Node Display Node Printer ridge Local rea Network Programmable Logic Controllers 14 7

8 Management Quality Control Engineering Mainframe LN ridge Display Client Display Client Display Client Display Client File Server LN larm Server Trends Server Report Server I/O Server Radio Modem RTU #1 LN LN RTU # PLC #1 PLC # PLC #3 PLC #4 PLC #5 PLC #6 15 Industrial Communications Protocols 8

9 Topics EI-3 Interface Standard EI-485 Interface Standard MODUS Protocol DNP 3.0 Protocol RS-3 Connections (D5) 9

10 Protocol nalyzer Connections Protocol nalyzer 10

11 RS-485 Review EI-485 interface standard Distances of up to 100m Data Rates of up to 10Mbps 3 Line Drivers 3 Line Receivers NOTE : Total of 3 devices on same line 11

12 RS-485 Is the Most Common Voltage Standard in Use Today for Multi-drop Communication Systems. This Is ecause RS 485 It Is Very Resistant to Noise It Can Send Data at High Speeds nd Can Go Long Distances Two Wire Multidrop RS M (4000 FT) TERMINTION RESISTORS T OTH ENDS ONLY G Rt Rt R TX RX R G TX RX GWG GWG G - Generator G G R - Receiver TX RX R TX RX R - Circuit ground or circuit common - Protective ground or frame ground GWG GWG GWG - Green wire ground or power system ground Note: The RS-485 standard documentation leaves out the invertes for the receiver 1

13 Four Wire Network 100M (4000 FT) Master Slave G Rt Rt R TX RX R Rt Rt G TX RX GWG GWG Slave Slave G - Generator G G R - Receiver TX RX R TX RX R - Circuit ground or circuit common - Protective ground or frame ground GWG GWG GWG - Green wire ground or power system ground Note: The RS-485 standard documentation leaves out the invertes for the receiver Installation of ias Resistors to Minimize Noise 560Ω 10Ω 560Ω 10Ω 13

14 MODUS Modbus Message Format 14

15 Modbus PLC Notation Messages & Functions Two types of messages: Query/response - specific slave addressd roadcast - address 00, no response required Function codes specify: what the slave is to do what section of the memory map to find or deposit the data e.g. Coil Status, Input Status, Input Register, Holding Register 15

16 What is DNP3? Distributed Network Protocol Version 3.0 Defines communications between: Master Stations Remote Telemetry Units (RTUs) Intelligent Electronic Devices (IEDs) More than just communications Originally developed in Electrical Utility Industry Designed for SCD Features Time stamping Optimised use of bandwidth Reporting by exception Variety of operating modes Data Structure nalogs inary Counters 16

17 Why use DNP3? It is an open protocol It is optimised for SCD communications It provides interoperability between different vendor s equipment It is supported by a substantial number of SCD equipment manufacturers It will provide immediate and long-term benefits to users Features of DNP3 Supports time stamped messages for Sequence of Event (SOE) recording reaks messages into multiple frames to provide optimum error control and rapid communication sequences llows peer-peer topology as well as master-slave llows multiple master topology Provides user definable objects Provides for reporting by exception / event without polling by master Provides for changed data only responses roadcast messages Secure configuration/file transfers ddressing for over 65,000 devices on a single link Provides Time synchronisation and time-stamped events Data link and application layer confirmation 17

18 Troubleshooting and Maintenance 18

19 Troubleshooting the telemetry system Ensure that components are not removed on line whilst the system is powered up unless the manufacturer specifically indicates that this is permissible. Damage to components and modules can occur when removing whilst the system is still powered up. Ensure that the antenna system is not disconnected from the system unless a dummy load has been installed, otherwise the radio power amplifier may be damaged. The RTU and component modules Check: nalog input modules Digital input module Interface from RTU to PLC (RS-3 / RS-485) Privately owned cable Switched telephone line nalog or digital data links 19

20 The master sites The master sites will generally consist of a more complete telemetry unit and higher quality radio equipment. The same troubleshooting techniques can be applied to the master site as are used at the RTUs. dditional equipment would include links to other master sites, to the central site and computer control facilities The central site The operator stations The software for the system The communications network for the operator stations 0

21 The operator station and software There is not much that can be done here if a system fails or has intermittent problems except to systematically replace each connected unit to identify the faulty module Operator terminal (normally a personal computer) Local area network card(s) ridge unit to radio, microwave or landline system Printer connected to operator terminal There are however a few problems which can be examined: Operator terminal locks up intermittently Throughput of the operator station and associated system drops off dramatically 1

22 Maintenance tasks Whether the maintenance tasks are to be undertaken internally by your company or outsourced to a maintenance contractor, it is vital that there is a comprehensive and planned approach to maintenance Tasks should be broken down in to those things done daily, weekly, monthly and annually. The maintenance unit system In industry today there is an increasing tendency for companies to reduce permanent staff to cover only the core business of the company and to contract out peripheral activities to specialist maintenance companies.

23 THNK YOU FOR TTENDING If you are interested in further training please visit; IDC Technologies Two-day practical workshops available to the public: On-site customised workshops: Technical Manuals: Conferences: The Engineering Institute of Technologies Practical online Certificate, dvanced Diploma and Graduate Certificate programs: If you are interested in further training in the area visit: Practical SCD Systems for Industry CITY COUNTRY DTE DYS Dublin Ireland 08-Mar-1 uckland New Zealand 16-pr-1 Practical oiler Control and Instrumentation for Engineers and Technicians CITY COUNTRY DTE DYS Johannesburg South frica 08-Mar-1 Vancouver Canada 15-Mar-1 Edmonton Canada 19-Mar-1 Toronto Canada -Mar-1 London United Kingdom 1-pr-1 irmingham United Kingdom 16-pr-1 Edinburgh United Kingdom 19-pr-1 uckland New Zealand 14-Jun-1 3

24 If you are interested in further training in the area visit: Practical Distributed Control Systems (DCS) for Engineers & Technicians CITY COUNTRY DTE DYS Johannesburg South frica 10-May-1 Vancouver Canada 4-May-1 Edmonton Canada 8-May-1 Montreal Canada 31-May-1 Practical Industrial Flow Measurement for Engineers and Technicians CITY COUNTRY DTE DYS Edinburgh United Kingdom 03-May-1 Manchester United Kingdom 10-May-1 Cardiff United Kingdom 14-May-1 Practical Instrumentation for utomation and Process Control CITY COUNTRY DTE DYS Johannesburg South frica 16-pr-1 If you are interested in further training in the area visit: CITY Sydney Perth Melbourne Practical Intrinsic Safety for Engineers and Technicians COUNTRY DTE ustralia 1-pr-1 ustralia 16-pr-1 ustralia 19-pr-1 DYS CITY Johannesburg Practical Tuning of Industrial Control Loops COUNTRY DTE South frica 3-Feb-1 DYS Practical Process Control CITY COUNTRY DTE DYS Johannesburg South frica 04-Jun-1 CITY Edmonton Winnipeg Halifax Practical Control Valve Sizing, Selection and Maintenance COUNTRY DTE Canada 1-Jun-1 Canada 5-Jun-1 Canada 8-Jun-1 DYS 4