hmi and scada

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    Human Machine Interface (HMI) Systemsprovide the controls by which a user operates a machine, system, or

    instrument. Sophisticated HMI Systems enable reliable operations of technology in every application, including high-

    speed trains, CNC machining centers, semiconductor production equipment, and medical diagnostic and laboratory

    equipment. HMI Systems encompass all the elements a person will touch, see, hear, or use to perform control

    functions and receive feedback on those actions.

    The task of an HMI System is to make the function of a technology self-evident to the user. A well-designed HMI fits

    the users image of the task he or she will perform. The effectiveness of the HMI can affect the acceptance of the

    entire system; in fact in many applications it can impact the overall success or failure of a product. The HMI System is

    judged by its usability, which includes how easy it is to learn as well as how productive the user can be.

    It is the mission of everyone involved in the HMI design, the engineers, management, HMI consultant, and industrial

    designer, to meet the defined usability requirements for a specific HMI System.

    A well-designed HMI System does more than just present control functions and information; it provides an operator

    with intuitive active functions to perform, feedback on the results of those actions, and information on the systems


    How to Design an HMI System

    A highly-reliable HMI System that delivers safe, cost-effective, consistent and intuitive performance relies on the

    application of engineering best practices throughout design and panel layout, production, testing, and quality

    assurance processes.

    Just as critical, in-depth knowledge of and compliance with all relevant ergonomic, safety, and industry standards

    must inform each step of the design and manufacturing cycle.

    Clear definitions of the functional requirements, the operators level of expertise, and any

    communications/interactions with other systems provide the starting point in the knowledge-intensive design process.

    Defining Operational/Functional Requirements

    The tools needed for effective operator control of the equipment as well as

    the requirements of the overall application determine the selection of

    interface functions.

    General Functionality

    How many functions will be controlled by this interface? Where a single function might be served by pushbutton,

    keylock, and rotary switches, multiple functions could require several screen displays to cover operator functions and
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    options. What kind of visual, auditory, or tactile feedback will best serve the operator in performing the defined


    Does the operation require real-time indicators? Multiple data-entry points? How many times is a button pressed? Are

    there safety considerations? Are emergency stop switches required? Which standards apply industry, safety,


    Degree of Input Complexity

    Input can be as simple as an on/off switch or a touchscreen display. Touchscreen HMI Systems are increasingly

    popular in public transaction applications, because they can simplify complex operations and tolerate a moderate

    degree of rough use. Defining input requirements will help decide which control technology is best suited for a

    specific application.

    Operator Feedback

    Feedback is critical to operator effectiveness and efficiency. Feedback can be visual, auditory, tactile, or any

    combination necessary for the application. Feedback is essential in systems that have no mechanical travel, such as

    a touchscreen or a capacitive device that when triggered has no moving parts. In some cases feedback provides

    confirmation of an action, while in others it adds to the functionality.

    Interface/Interconnection with Other Systems

    HMI Systems must be able to interface/interconnect with the system under control as well as other related systems.

    For example, in an industrial setting the HMI might connect via hardwire or a serial bus to I/O points that provide

    machine status. Additionally, it might be networked to a manufacturing execution system and a supply

    logistics/inventory system.

    Environmental Considerations

    The application environment encompassing both physical location and vertical industry environment determines

    HMI System durability requirements. Environmental stresses include exposure to moisture and the elements,

    temperature extremes, wear and tear, vandalism, and general rough use characteristic of harsh environments such

    as an industrial production floor.

    Lifecycle Durability

    Not only should the HMI System be rugged enough to withstand the elements and heavy use, but it should also last

    for the duration of the equipment lifecycle. For example, a Magnetic Resonance Imaging (MRI) HMI System interface

    should last at least 10 years.


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    HMI System style is a high priority for many consumer goods and especially luxury products. In the marine industry,

    the consoles for high-performance racing boats feature contemporary styling and an array of ergonomic technologies.

    HMI style considerations are effective when they create a level of product differentiation that delivers a unique selling


    Regulatory/Standards Considerations

    A thorough knowledge of technical ergonomic, design, and manufacturing standards is fundamental to HMI System

    design. These include engineering standards, such as MIL-STD-1472F, which establishes human engineering design

    criteria for military systems, subsystems, equipment, and facilities; federal standards set by the Americans With

    Disabilities Act; and industry guidelines such as those from SEMI S2-93, the global semiconductor industry

    association, covering HMI for semiconductor manufacturing equipment. Additional HMI specifications are defined by

    ANSI, IEEE, ISO, and others.

    Define the Operator

    Know your operator the key to a successful HMI System implementation

    requires a well-grounded definition and understanding of the operators. Will

    the operator be a passive/intuitive user? If so, commands/functions should be

    simple with an easy-to-comprehend interface. For this type of user,

    repeatability is also important information and actions should appear

    consistently from use to use. For an expert user, where more sophisticated

    control is desirable, there may be multiple layers or levels for interfacing with


    For any user along the range from intuitive to expert, interface ergonomic considerations should include: panel layout,HMI Component selection, information presentation, feedback, and safety considerations.

    Panel Layout

    The panel layout should be designed to provide the operator functional groups of related information in a predictable

    and consistent manner. In addition, the system must require an operator to initiate action and keep the operator

    informed by providing timely feedback on those actions. The layout should be organized so that the operator is clearly

    prompted in advance when the next operator action is required.

    HMI Component selection

    HMI designers can simplify their search for the appropriate switch or HMI Component by carefully analyzing their

    application requirements then determining the following:

    Electrical ratings.

    Actuation preferences (momentary, maintained, rotary, etc.).

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    Physical configuration and mounting needs.

    Special requirements such as illumination, marking, environmental sealing, etc.

    Color scheme

    The key to effective use of color is simplicity. Avoid too many colors or flashing alarms. Stick with the traffic light

    model for key actions:

    Red for stop/failure/fault.

    Yellow for warning.

    Green for OK/start/go/pass.

    Information presentation

    Once again, simplicity is the key. Dont crowd a screen avoid cluttering it with irrelevant data. Forcing an operator to

    search for the required information increases response time and potential errors. Have a consistent set of menu

    buttons and functions from screen to screen.

    User Feedback

    Feedback is critical to ergonomic industrial design. Make sure the results of pressing a control button, toggling a

    switch, or entering a command are absolutely clear. Determine if operator feedback is visual, auditory, tactile, or a

    combination of multiple techniques.

    Choosing the Best Control Technologies

    Once you have defined HMI functionality, you are ready to investigate control technologies. Each technology has

    advantages and disadvantages related to the HMI system, equipment, and application.

    Cursor Control (Trackball, joystick, keypad, touchpad, etc.)

    The selection between different control technologies is primarily determined by the resolution of control that is

    required by the application. A trackball or joystick enables granular, pixel-by-pixel control, a far higher resolution than

    possible with a typical PC point-and-click controller.

    Switches (Pushbutton, rocker, slide, keylock, rotary, etc.)

    Pushbut ton sw i tchesallow the option of illumination to indicate open/close switch status when a quick visual

    indication is desired. They are also useful in machinery and machine tools, electronic production, rail and bus

    transportation, medical treatment and diagnostics, or other environments for easier manipulation when gloves are


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    Rotary-switch and keylock techno logiesserve best when the application requires position indicators such as those

    used in heater or fan control. Keylocks provide an additional layer of security to the application. Rotary switches also

    can be used for an application requiring multiple positions.

    Slide switchesare the technology of choice when ease-of-use and low-cost switching is desirable commonly found

    on notebook cases and handheld on/off functionality.

    Short travel technologies (Conductive rubber, membrane, keyboard, keypad, etc.)

    Short t ravel technologieshave been developed for industries where ease of cleaning or disinfecting is mandatory,

    for example pharmaceutical, chemical, and food processing, or in a hazardous environment where a sealed system is

    required. Short travel technology can include cost effective, conductive rubber keys in a typical keyboard, dome keys

    under an overlay, or a multi-layer membrane.

    Touch and switching technologies, (Capacitive, Piezo, high frequency, etc.)

    Applications operating in aggressive environments such as public access or, for example, soda dispensing, where the

    syrupy liquid tends to get into crevices and gum up the machinery require a rugged, completely sealed surface.

    Piezo, capacitive, and high frequency technologies all offer rugged switch technology with long life cycles and low

    maintenance costs.

    Capacitive or high-frequency signals electronically activate an on/off function by changing capacitive load.

    Capacitive/high-frequency technologies require the use of nonconductive front panel materials which can be up to 15

    mm thick, for example those operating under protective glass within hazardous environments.

    Display technologies (LCD, Active Matrix, OLED, FED, Plasma, etc.)

    The basic function of displays in HMI applications is to provide an information source operators interact to obtain

    information or to prompt for the next screen. Display technology choices are dictated by the HMI System environment

    and its degree of ambient illumination, as well as by color requirements. Active matrix LCD technologies are

    commonly used for color functionality, while legacy LCD technology is used in applications where monochromatic

    feedback is sufficient. OLEDS, organic (carbon-based) light-emitting diodes can currently support smaller displays.

    Interactive Displays, Touchscreen

    Touchsc reen technologiesoffer a range of functionalities and characteristics that govern HMI Systems choice

    according to application and environment. It is important to determine which touch technology will be used in the early

    stages of the design cycle as the different options offer quite unique electrical and mechanical requirements.

    Capacit ive touchscreentransmit 75 percent of the monitor light (compared to 50 percent by Resistive

    touchscreens), resulting in a clearer picture. They use only conductive input, usually a finger, in order to register a


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    Inf rared tou chscreentechnology projects horizontal and vertical beams of infrared light over the surface of the

    screen. When a finger or other object breaks those beams, the X/Y coordinates are calculated and processed. These

    cost-effective touchscreens can also be used by workers with gloves and are relatively impervious to damage.

    Resist ive touchscreentechnology offers cost-effective, durable performance in environments where equipment

    must stand up to contaminants and liquids, such as restaurants, factories, and medical environments. When touched,

    the conductive coating on the screen makes electrical contact with the coating on the outer layer, the touch

    coordinates are registered by the controller to activate the on/off function.

    Surface Acoust ic Wave (SAW)touch technology sends acoustic waves across a glass surface from one transducer

    to another positioned on an X/Y grid. The receiving transducer detects if a wave has been disrupted by touch and

    identifies its coordinates for conversion to an electrical signal. SAW serves well in outdoor and harsh environments

    because it can be activated by a heavy stylus or gloved fingers.

    Motion Control

    Motion control most often employs joystick technology for applications requiring macro control, such as controlling the

    bucket on a payloader, a robotic arm, or directional control for a piece of materials handling equipment, or pull


    Connecting/Communicating with an HMI System

    Once you have established how your HMI will look, feel, and operate, you need to consider how the HMI will connect

    to and communicate with the core equipment or system under control. Typically, communication can be achieved

    through several approaches: hard wired connection, serial bus connection, or wireless connection.

    Hard-Wired Connections

    Conventional, hard wired systems are still used in many transportation and industrial legacy systems. Hard wired

    systems require no special tools and are simple, visible, and easy to understand, especially where the HMI interface

    controls a single machine.

    There are many drawbacks, including difficulty integrating changes or new features new features require new

    wiring. Conventional wiring also requires more space due to the number of wires and the actual size of the wires and

    larger connectors due to higher pin counts.

    Serial Bus Systems

    As equipment and control systems became more complex and data hungry, transmission of data became a critical

    issue. To facilitate faster data transmission rates, devices incorporated serial bus connections especially in

    electronics, semiconductor, machining, industrial, process and transportation. A serial bus approach eliminated data

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    transmission slowdowns due to cable length and delivered reliable, real-time operations and work-in-process


    Bus systems provide many advantages over hard wired connections, including easy addition of new functionality

    typically through software without adding or replacing hardware. Wiring is much simpler and more flexible with

    smaller cables and connectors allowing for more compact design, and easier hardware updating and relocation.

    Field bus protocols evolved for interconnecting industrial drives, motors, actuators and controllers. Field buses

    include: PROFIBUS, DeviceNet, ControlNet, CAN/CANOpen, InterBus, and Foundation Field Bus.

    Higher level networks connect with field bus protocols primarily across variations of Ethernet. These include:

    PROFINET, Ethernet/IP, Ethernet Powerlink, EtherCAT, Modbus-TCP and SERCOS III.

    Wireless Connections/Communications

    Industrial applications have employed wireless technologies over the last 20 or so years, primarily to take advantage

    of real-time data transmission, application mobility, and remote management capabilities. Interference, reliability, and

    security continue to present difficulties for wireless in the HMI universe.

    Safety Considerations

    For HMI Systems design, safety considerations are a critical part of the system. Human error is a contributing factor

    in most accidents in high-risk environments. Clear presentation of alarms as well as the ability to report errors, are

    crucial elements in any HMI.

    In addition, emergency stop switches, generally referred to as E-Stops, ensure the safety of persons and machinery

    and provide consistent, predictable, failsafe control response. A wide range of electrical machinery must have these

    specialized switch controls for emergency shutdown to meet workplace safety and established international and

    domestic regulatory requirements.

    International and U.S. Standards for HMI Systems

    Key to the entire HMI System design cycle is a thorough knowledge of federal, industry, ergonomic, safety, and

    design standards. These include Human Engineering standards, such as MILSTD-1472F, which establishes human

    engineering design criteria for military systems, subsystems, equipment, and facilities; federal standards like those

    set by the Americans with Disabilities Act; and industry guidelines such as those from SEMI, the global

    semiconductor industry association, covering HMI for semiconductor manufacturing equipment.

    Additional HMI specifications are furnished by ANSI, IEEE, ISO, and others. The EU provides specifications in its EU

    Machinery Directive for any equipment for domestic, commercial, or industrial applications that have parts actuated

    by a power source other than manual effort. Meeting this directive earns the equipment a CE mark.

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    There are also standards for public access HMI Systems, including security and cryptography standards for systems

    that handle payment cards; specific flammability standards and test procedures for transportation systems, and

    medical device and equipment standards.

    Depending on the ultimate product application, observing appropriate standards assures that a product will meet

    industry criteria. This includes placement of components, legend size and color, emergency stop switch configuration

    and guards, and other ergonomic factors that improve usability, efficiency, and safety.

    For more informat ion on sw itches, check


    How This Tutorial Will Help You

    SCADA monitoring and control can save you a lot of money and increase profitability but

    your SCADA implementation can be a sinkhole of cost overruns, delays and limited


    This Tutorial will explain the essentials of SCADA technology, give you guidelines for

    evaluatingSCADAtechnology and help you decide what kind of SCADA system is best for

    your needs.


    Section I: What Is SCADA, and What Can It Do for You? 4

    Where Is SCADA Used? 4

    What's The Value OfSCADAto You? 5

    Real-Time Monitoring And Control Increases Efficiency and Maximizes Profitability 5

    Section 2: How SCADA Systems Work 6

    The World's Simplest SCADA System 7

    Data Acquisition 7

    Data Communication 8
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    Data Presentation 9

    Control 9

    Section 3: How to Evaluate SCADA Systems and Hardware 10

    The Two Most Important Components of YourSCADASystem 10

    A Brief Note on Sensors and Networks 10

    What to Look for in aSCADA RTU(Remote Telemetry Unit) 11

    What to Look for in a SCADA Master 12

    Section 4:T/Mon NOC- An IntegratedSCADAMonitoring and Control Solution 13

    How Do You Know ThatT/MonNOC Will Work for You? 14

    What Do Real People Who UseT/Mon NOCSay? 14

    Why You Need Help With Your SCADA Implementation 14

    I'm Ready to Take a Serious Look at T/Mon NOC - What Do I Do Next? 15

    My Promise to You 15

    DPS Telecom's Sales Department: Monitoring Consultants Who Put You First 16

    T/Mon NOCProduct Data Sheet 18

    Section 1: What is SCADA, and what can it do for you?

    SCADA is not a specific technology, but a type of application.SCADAstands for SupervisoryControl and Data Acquisition - any application that gets data about a system in order tocontrol that system is a SCADA application.

    A SCADA application has two elements:

    1. The process/system/machinery you want to monitor a control - this can be a power plant,a water system, a network, a system of traffic lights, or anything else.

    2. A network of intelligent devices that interfaces with the first system through sensors and

    control outputs. This network, which is the SCADA system, gives you the ability to measureand control specific elements of the first system.
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    You can build aSCADAsystem using several different kinds of technologies and protocols.

    This white paper will help you evaluate your options and decide what kind of SCADA systemis best for your needs.

    Where is SCADA Used?

    You can use SCADA to manage any kind of equipment. Typically,SCADAsystems are used

    to automate complex industrial processes where human control is impractical - systemswhere there are more control factors, and more fast-moving control factors, than human

    beings can comfortably manage.

    Around the world, SCADA systems control:

    Electric power generation, transmission and distribution: Electric utilities use

    SCADA systems to detect current flow and line voltage, to monitor the operation of circuitbreakers, and to take sections of the power grid online or offline.

    Water and sewage: State and municipal water utilities use SCADA to monitor andregulate water flow, reservoir levels, pipe pressure and other factors.

    Buildings, facilities and environments: Facility managers useSCADAto control

    HVAC, refrigeration units, lighting and entry systems.

    Manufacturing: SCADA systems manage parts inventories for just-in-time

    manufacturing, regulate industrial automation and robots, and monitor process and qualitycontrol.

    Mass transit: Transit authorities use SCADA to regulate electricity to subways, trams

    and trolley buses; to automate traffic signals for rail systems; to track and locate trains andbuses; and to control railroad crossing gates.

    Traffic signals: SCADA regulates traffic lights, controls traffic flow and detects out-of-

    order signals.

    As I'm sure you can imagine, this very short list barely hints at all the potential applications

    forSCADAsystems. SCADA is used in nearly every industry and public infrastructure project- anywhere where automation increases efficiency.

    What's more, these examples don't show how deep and complex SCADA data can be. In

    every industry, managers need to control multiple factors and the interactions betweenthose factors. SCADA systems provide the sensing capabilities and the computational powerto track everything that's relevant to your operations.

    What's the Value ofSCADAto You?

    Maybe you work in one of the fields I listed; maybe you don't. But think about youroperations and all the parameters that affect your bottom-line results:
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    Does your equipment need an uninterrupted power supply and/or a controlled

    temperature and humidity environment?

    Do you need to know - in real time - the status of many different components and

    devices in a large complex system?

    Do you need to measure how changing inputs affect the output of your operations?

    What equipment do you need to control, in real time, from a distance?

    Where are you lacking accurate, real-time data about key processes that affect your


    Real-Time Monitoring and Control Increases Efficiency and MaximizesProfitability

    Ask yourself enough questions like that, and I'm sure you can see where you can apply a

    SCADA system in your operations. But I'm equally sure you're asking "So what?" What youreally want to know is what kind of real-world results can you expect from using SCADA.

    Here are few of the things you can do with the information and control capabilities you getfrom a SCADA system:

    Access quantitative measurements of important processes, both immediately and over


    Detect and correct problems as soon as they begin

    Measure trends over time

    Discover and eliminate bottlenecks and inefficiencies

    Control larger and more complex processes with a smaller, less specialized staff.

    ASCADAsystem gives you the power to fine-tune your knowledge of your systems. Youcan place sensors and controls at every critical point in your managed process (and as

    SCADA technology improves, you can put sensors in more and more places). As you

    monitor more things, you have a more detailed view of your operations - and mostimportant, it's all in real time.
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    So even for very complex manufacturing processes, large electrical plants, etc., you can

    have an eagle-eye view of every event while it's happening - and that means you have a

    knowledge base from which to correct errors and improve efficiency. With SCADA, you cando more, at less cost, providing a direct increase in profitability.

    How SCADA Systems Work

    ASCADAsystem performs four functions:

    1. Data acquisition

    2. Networked data communication

    3. Data presentation

    4. Control

    These functions are performed by four kinds of SCADA components:

    1. Sensors (either digital or analog) and control relays that directly interface with themanaged system.

    2. Remote telemetry units (RTUs). These are small computerized units deployed in the

    field at specific sites and locations. RTUs (Remote Telemetry Units) serve as local collectionpoints for gathering reports from sensors and delivering commands to control relays.

    3. SCADA master units. These are larger computer consoles that serve as the centralprocessor for the SCADA system. Master units provide a human interface to the system andautomatically regulate the managed system in response to sensor inputs.

    4. The communications network that connects theSCADAmaster unit to the RTUs in thefield.

    DPS Telecom Remote Site Survey

    RTU (Remote Telemetry Unit) Capacity and Function

    1. How many remote sites do you need to monitor?

    2. Do you want video surveillance at those sites?

    3. Do you want a building access control system to manage entry to those sites?

    4. How many alarm points do you need to monitor at each site?

    5. How much growth, in sites and alarms at each site, do you anticipate over the next 5years?

    6. Do you need any analog inputs (e.g., voltage, temperature, humidity, signal strength)?
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    7. How many ASCII device (e.g., switches, routers, etc.) will you monitor at your remotesites?


    1. How do you currently connect to your remote sites? (LAN, overhead, digital or analogcircuit, terminal server,microwave?)

    2. Do any of your sites support an alternate path communications link?

    3. What type of power do you have at the master and remote sites? (-48 VDC, 110 VAC,other?)

    4. How do you want to mount your RTUs (Remote Telemetry Units)? (23" rack, 19" rack,wall, tabletop?)

    5. Who will install your RTUs?

    This is just a small sample of the DPS Telecom Remote Site Survey. The full Remote SiteSurvey is a complete 5-page guide to evaluating yournetwork alarm monitoringneeds.For your copy of the Remote Site Survey, call DPS Telecom at 1-800-693-0351.

    The World's Simplest SCADA System

    The simplest possible SCADA system would be a single circuit that notifies you of one event.

    Imagine a fabrication machine that produces widgets. Every time the machine finishes a

    widget, it activates a switch. The switch turns on a light on a panel, which tells a humanoperator that a widget has been completed.

    Obviously, a realSCADAsystem does more than this simple model. But the principle is thesame. A full-scale SCADA system just monitors more stuff over greater distances.

    Let's look at what is added to our simple model to create a full-scale SCADA system:

    Data Acquisition
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    First, the systems you need to monitor are much more complex than just one machine with

    one output. So a real-life SCADA system needs to monitor hundreds or thousands of

    sensors. Some sensors measure inputs into the system (for example, water flowing into areservoir), and some sensors measure outputs (like valve pressure as water is released

    from the reservoir).Some of those sensors measure simple events that can be detected by a straightforward

    on/off switch, called a discrete input (or digital input). For example, in our simple model ofthe widget fabricator, the switch that turns on the light would be a discrete input. In real

    life, discrete inputs are used to measure simple states, like whether equipment is on or off,or tripwire alarms, like a power failure at a critical facility.

    Some sensors measure more complex situations where exact measurement is important.

    These are analog sensors, which can detect continuous changes in a voltage or currentinput. Analog sensors are used to track fluid levels in tanks, voltage levels inbatteries,temperature and other factors that can be measured in a continuous range of input.

    For most analog factors, there is a normal range defined by a bottom and top level. Forexample, you may want the temperature in a server room to stay between 60 and 85

    degrees Fahrenheit. If the temperature goes above or below this range, it will trigger athreshold alarm. In more advanced systems, there are four threshold alarms for analogsensors, defining Major Under, Minor Under, Minor Over and Major Over alarms.

    This RTU (Remote Telemetry Unit) Grows with Your Network

    When you're planning your alarm monitoring, think about the future. You don't want to getlocked into an alarm system that's inadequate for your future needs - but you don't want tospend too much for alarm capacity you won't immediately use, either.

    TheNetGuardian 832Aremote telemetry unit expands its capacity as your needs change.Install a NetGuardian at your remote site now, and get exactly the right coverage for your

    current needs.

    Then, as your remote site grows, you can extend your alarm monitoring capabilities by

    addingNetGuardianDX Expansion units. Each NetGuardian DX adds 48 more alarm points,and you can daisy-chain up to three NetGuardian DXs off each NetGuardian 832A base unit.

    Unit Capacity

    Base NG 832 32

    1 DX 80

    2 DX 128

    3 DX 176
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    Data Communication

    In our simple model of the widget fabricator, the "network" is just the wire leading from the

    switch to the panel light. In real life, you want to be able to monitor multiple systems from

    a central location, so you need a communications network to transport all the data collectedfrom your sensors.

    Early SCADA networks communicated over radio, modem or dedicated serial lines. Today

    the trend is to put SCADA data on Ethernet and IP over SONET. For security reasons,SCADA data should be kept on closed LAN/WANs without exposing sensitive data to theopen Internet.

    RealSCADAsystems don't communicate with just simple electrical signals, either. SCADA

    data is encoded in protocol format. Older SCADA systems depended on closed proprietaryprotocols, but today the trend is to open, standard protocols and protocol mediation.

    Sensors and control relays are very simple electric devices that can't generate or interpretprotocol communication on their own. Therefore the remote telemetry unit (RTU) is neededto provide an interface between the sensors and the SCADA network. The RTU (Remote

    Telemetry Unit) encodes sensor inputs into protocol format and forwards them to

    theSCADAmaster; in turn, the RTU (Remote Telemetry Unit) receives control commandsin protocol format from the master and transmits electrical signals to the appropriate control


    WhatRTU(Remote Telemetry Unit) Features Do You Need?

    How do you find the right RTU (Remote Telemetry Unit)? Here's 5 essential features to look

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    1. Discrete alarms: Monitor device failures, intrusion alarms, beacons, and flood and firedetectors.

    2. Analog alarm inputs: Monitor voltage, temperature, humidity and pressure.

    3. Control relays: Operate remote site equipment directly from your SCADA master.

    4. Redundant backup communication: Backup serial ports and/or internal modems willkeep your monitoring online even during a LAN failure.

    5. Redundant backup power inputs: Dual power inputs and battery backup keepmonitoring online, even during power failures.

    DPS Telecom offers RTUs that meet all these requirements - and offer local visibility via Webbrowser, email and pager notification, and more.

    For more information about DPS RTUs, see us on the Web at

    How to select an RTU that covers all your remote monitoring needs

    Migrate to LAN Without Killing Your Budget

    Installing LAN connections at remote sites is a significant cost - but you can spread if overseveral budget cycles through LAN migration. Here's how:

    Step One: Install a LAN + Dial-Up/Serial RTU (Remote Telemetry Unit)

    First, install anRTU(Remote Telemetry Unit) that supports both LAN and your existing dial-up or serial transport, like the NetGuardian 832A

    Step Two: Install a LAN Connection

    When it fits into your budget, install a LAN connection at the remote site. The

    sameNetGuardianunit can be immediately switched to reporting over LAN with minimalconfiguration - and you don't have to rewire any alarms.

    Gradually migrate different sections of your network to LAN, as your budget and installationmanpower allows.

    Benefits of LAN Migration

    Installation costs are spread over several budget cycles

    Buy just one RTU (Remote Telemetry Unit) for both LAN andlegacytransport
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    Deploy SCADA NOW at all your locations

    More Info Resouces on the Web

    The DPS Telecom White Paper Series offers a complete library of helpful adviceand survival guides for every aspect of system monitoring and control.

    Data Presentation

    The only display element in our model SCADA system is the light that comes on when the

    switch is activated. This obviously won't do on a large scale - you can't track a lightboard of

    a thousand separate lights, and you don't want to pay someone simply to watch alightboard, either.

    A realSCADAsystem reports to human operators over a specialized computer that isvariously called a master station, an HMI (Human-Machine Interface) or an HCI (Human-

    Computer Interface).

    The SCADA master station has several different functions. The master continuously

    monitors all sensors and alerts the operator when there is an "alarm" - that is, when acontrol factor is operating outside what is defined as its normal operation. The masterpresents a comprehensive view of the entire managed system, and presents more detail in

    response to user requests. The master also performs data processing on informationgathered from sensors - it maintains report logs and summarizes historical trends.

    An advanced SCADA master can add a great deal of intelligence and automation to yoursystems management, making your job much easier.


    Unfortunately, our miniature SCADA system monitoring the widget fabricator doesn't include

    any control elements. So let's add one. Let's say the human operator also has a button on

    his control panel. When he presses the button, it activates a switch on the widget fabricatorthat brings more widget parts into the fabricator.

    Now let's add the full computerized control of aSCADAmaster unit that controls the entirefactory. You now have a control system that responds to inputs elsewhere in the system. If

    the machines that make widget parts break down, you can slow down or stop the widget
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    fabricator. If the part fabricators are running efficiently, you can speed up the widgetfabricator.

    If you have a sufficiently sophisticated master unit, these controls can run completely

    automatically, without the need for human intervention. Of course, you can still manuallyoverride the automatic controls from the master station.

    In real life, SCADA systems automatically regulate all kinds of industrial processes. Forexample, if too much pressure is building up in a gas pipeline, the SCADA system canautomatically open a release valve. Electricity production can be adjusted to meet demands

    on the power grid. Even these real-world examples are simplified; a full-scale SCADAsystem can adjust the managed system in response to multiple inputs.

    T/MonNOC Automatically Troubleshoots and Corrects Problems

    The same alarm can instantly go from minor to critical if something else goes wrong. Forexample, a low battery might not be a big deal until AC power and the backup generatorboth fail, and then it's an emergency.

    T/Mon NOC's Derived Alarms feature gives you the power to instantly track these kinds ofchanging alarm conditions. Derived Alarms combine inputs from multiple alarm points into a

    single, software-configured alarm, using simple Boolean logic.

    Let's say your low battery is a minor alarm. Low battery AND an AC power failure OR

    generator failure is a major. Low battery AND AC power failure AND generator failure is acritical alarm.

    Correct Alarms Instantly With No Human Intervention

    T/Mon NOC's Derived Controls are even more useful, correcting problems before any human

    operator even knows something is wrong.

    If critical network equipment fails,T/Mon NOCcan automatically start backup equipment

    and notify a service tech. If a security door is breached after-hours,T/MonNOC canautomatically lock security gates, turn on lights, and page security staff.

    How to EvaluateSCADASystems and Hardware
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    SCADA can do a lot for you - but how do you make sure that you're really getting the full

    benefits of SCADA? Evaluating complex systems can be tricky - especially if you have tolearn a new technology while still doing your everyday job.

    But you've got to be able to make an informed decision, because the stakes are incredibly

    high. A SCADA system is a major, business-to-business purchase that your company will

    live with for maybe as long as 10 to 15 years. When you make a recommendation about apermanent system like that, you're laying your reputation on the line and making a majorcommitment for your company.

    And as much asSCADAcan help you improve your operations, there are also some pitfallsto a hasty, unconsidered SCADA implementation:

    You can spend a fortune on unnecessary cost overruns

    Even after going way over budget, you can STILL end up with a system that doesn't

    really meet all your needs

    Or just as bad, you can end up with an inflexible system that just meets your needs

    today, but can't easily expand as your needs grow

    So let's go over some guidelines for what you should look for in a SCADA system.

    The Two Most Important Components of Your SCADA System

    Although you need sensors, control relays and a communications network to make a

    completeSCADAsystem, it's your choice of a master station and RTUs that really determinethe quality of your SCADA system.

    A Brief Note on Sensors and Networks

    Sensors and control relays are essentially commodity items. Yes, some sensors are better

    than others, but a glance at a spec sheet will tell you everything you need to know tochoose between them.

    An IP LAN/WAN is the easiest kind of network to work with, and if you don't yet have LAN

    capability throughout all your facilities, transitioning to LAN is probably one of your long-term goals. But you don't have to move to LAN immediately or all at once to get thebenefits of SCADA. The right SCADA system will support both your legacy network and LAN,enabling you to make a graceful, gradual transition.

    The Flexible RTU (Remote Telemetry Unit) That Handles All YourTransports
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    With theNetGuardian 832A, multiple transports are no problem.

    TheNetGuardiansupports LAN, dial-up and serial connections simultaneously. So as yournetwork upgrades fromlegacytransports to LAN, you can use the same NetGuardian unitsat all your sites.

    What can theNetGuardiando for you?

    You can use one RTU (Remote Telemetry Unit) at all your remote sites, no matter what

    transport is available.

    You don't have to install new transport to collect alarms.

    As your network changes, you don't have to buy new remotes for new transports.

    You only have to maintain one set of spare units and spare parts for your entire network,

    for great cost savings and convenience.

    What to Look for in aSCADA RTU(Remote Telemetry Unit)

    Your SCADA RTUs need to communicate with all your on-site equipment and survive under

    the harsh conditions of an industrial environment. Here's a checklist of things you shouldexpect from a quality RTU:

    Sufficient capacity to support the equipment at your site but not more capacity

    than you actually will use. At every site, you want an RTU (Remote Telemetry Unit)that can support your expected growth over a reasonable period of time, but it's

    simply wasteful to spend your budget on excess capacity that you won't use.

    Rugged construction and ability to withstand extremes of temperature andhumidity. You know how punishing on equipment your sites can be. Keep in mind

    that your SCADA system needs to be the most reliable element in your facility.

    Secure, redundant power supply. You need yourSCADAsystem up and working24/7, no excuses. YourRTU(Remote Telemetry Unit) should support battery power

    and, ideally, two power inputs.

    Redundant communication ports. Network connectivity is as important to SCADA

    operations as a power supply. A secondary serial port or internal modem will keepyour RTU (Remote Telemetry Unit) online even if the LAN fails. Plus, RTUs with

    multiple communication ports easily support a LAN migration strategy.

    Nonvolatile memory (NVRAM) for storing software and/or firmware. NVRAM

    retains data even when power is lost. New firmware can be easily downloaded to
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    NVRAM storage, often over LAN - so you can keep your RTUs' capabilities up to date

    without excessive site visits.

    Intelligent control. As I noted above, sophisticated SCADA remotes can control

    local systems by themselves according to programmed responses to sensor inputs.This isn't necessary for every application, but it does come in handy for some users.

    Real-time clock for accurate date/time stamping of reports.

    Watchdog timer to ensure that the RTU (Remote Telemetry Unit) restarts after apower failure.

    3 RTUs to Fit Your Spec and Budget

    The NetGuardian RTU (Remote Telemetry Unit) family scales to fit your needs


    32 discretes, 32 pings, 8 analogs and 8 controls

    8 terminal server serial ports

    NEBS Level 3 certified

    Dial-up backup

    Web browser interface

    Pager and email notification

    Dual -48 VDC, -24 VDC or 110 AC

    1 RU for 19" or 23" rack
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    80 discretes, 4 controls

    For SNMP ,TL1 orT/Mon NOC

    Dual -48 VDC

    1 RU for 19" or 23" rack

    EconomicalNetGuardian 216

    16 discretes, 2 analogs, 2 controls

    1 terminal server serial port

    For SNMP , TL1 or T/Mon NOC

    Single or dual -48VDC or 110 VAC

    2 compact form factors for rack or wall mount

    What to Look for in aSCADAMaster

    Your SCADA master should display information in the most useful ways to human operators

    and intelligently regulated your managed systems. Here's a checklist of SCADA mastermust-haves:

    Flexible, programmable response to sensor inputs. Look for a system thatprovides easy tools for programming soft alarms (reports of complex events that

    track combinations of sensor inputs and date/time statements) and soft controls(programmed control responses to sensor inputs).

    24/7, automatic pager and email notification. There's no need to pay personnelto watch a board 24 hours a day. If equipment needs human attention, the SCADA

    master can automatically page or email directly to repair technicians.
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    Detailed information display. You want a system that displays reports in plain

    English, with a complete description of what activity is happening and how you can

    manage it.

    Nuisancealarm filtering. Nuisance alarms desensitize your staff to alarm reports,and they start to believe that all alarms are nonessential alarms. Eventually they

    stop responding even to critical alarms. Look for aSCADAmaster that includes tools

    to filter outnuisancealarms. Expansion capability. A SCADA system is a long-term investment that will last for

    as long as 10 to 15 years. So you need to make sure it will support your future

    growth for up to 15 years.

    Redundant, geodiverse backup. The best SCADA systems support multiplebackup masters, in separate locations.. If the primary SCADA master fails, a second

    master on the network automatically takes over, with no interruption of monitoring

    and control functions.

    Support for multiple protocols and equipment types. EarlySCADAsystemswere built on closed, proprietary protocols. Single-vendor solutions aren't a great

    idea - vendors sometimes drop support for their products or even just go out of

    business. Support for multiple open protocols safeguards your SCADA system against

    unplanned obsolescence.

    For more in-depth look at SCADA

    Alarm Master Choice:T/Mon NOC

    T/MonNOC has many features to make your alarms more meaningful, including:

    1. Detailed, plain English alarm descriptions include severity, location and date/timestamp.

    2. Immediate notification of COS alarms, including new alarms and alarms that havecleared

    3. Standing alarm list is continuously updated.
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    4. Text message windows displaying specific instructions for the appropriate action for analarm.

    5. Nuisance alarm filtering, allowing your staff to focus its attention on serious threats.

    6. Pager and email notifications sent directly to maintenance personnel, even if they're

    away from the NOC.

    7. Derived alarms and controls that combine and correlate data from multiple alarm

    inputs and automatically control remote site equipment to correct complex threats.

    For more information, check out T/Mon on the Web

    Section 4:T/Mon NOC- An Integrated SCADA Monitoring and Control


    My company, DPS Telecom, manufacturesT/MonNOC, a master unit that serves as thecore of an integratedSCADAsystem for all your equipment.

    T/Mon NOCcan meet all the criteria I've listed for a superior SCADA master and can do

    a whole lot more.

    What Can T/MonNOC Do for You?

    T/Mon NOCprovides a single, one-screen view of all your monitored

    equipment.T/MonNOC will tell you 100% for certain whether anything has gone wrongwith any of your monitored equipment, so you can be absolutely sure there are no secretproblems anywhere in your system.

    T/Mon NOCcan monitor up to 1 million alarm points, giving you ample capacity to

    monitor everything in your facilities.
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    T/MonNOC presents information in simple, plain English, including detailed text

    messages telling system operators exactly what to do in case of an emergency.

    T/Mon NOC's Derived Alarms and Derived Controls let you automate every aspect of

    your systems using simple Boolean logic.

    You can filter alarms for the needs of different users. You can select which alarms are

    immediately forwarded to technicians via pager and email, which alarms can be viewed

    locally on theT/MonNOC console, and which alarms are just logged to a history file forrecording and later analysis.

    At every level of your organization, people can see the information they want without

    being bombarded withnuisancealarms.

    Actually, this list just scratches the surface ofT/Mon NOC's capabilities. For moreinformation about what T/MonNOC can do for you, see theT/MonNOC Product Data

    Sheet on page 16.

    5 Ways T/MonNOC Saves You Money

    1. It's a single unit solution.

    Instead of replacing every RTU (Remote Telemetry Unit) in your network, you canimmediately deployT/Mon NOCand start using SCADA monitoring NOW.

    2. Minimal installation costs.

    A DPS installer will set up and configure yourT/MonNOC for you compare that to the

    manpower costs of installing new RTUs at all your remote sites.

    3. Replace RTUs when YOU want.

    WithT/Mon NOC, your legacy RTUs are just fine doing what they're currently doing until

    you decide to replace them. You can keep them until they die or replace them wheneverreplacement will have the smallest impact on your budget.

    4. Keep your data transport.Whether yourlegacyRTUs report over a serial line, a dedicated circuit, an overhead

    channel or microwave, T/MonNOC supports your existing data transport.

    5. No vendor lock-in.

    When you upgrade toT/Mon, you're not trading in one closed system for another you're

    trading up to a true multiprotocol alarm system.

    How Can You Know ThatT/Mon NOCWill Work for You?
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    T/Mon NOC is not a new or untested product.T/Monunits have been in the field for years,

    successfully performing for clients who need stable, bulletproof monitoring and control tosupport their mission-critical operations.

    What Do Real People Who UseT/Mon NOCSay?

    "DPS Telecom gave us a reliable way of accessing a variety of equipment, regardless of the

    brand or provider. We now have a common interface for our existing system."Harold Moses, KMC Telecom

    "DPS told us we didn't have to pay if it didn't work. It works and it's sweet."

    Glenn Lippincott, Southern Company

    "It's hard to find companies with the intelligence and aptitude to meet the customer's exact

    needs, and I believe that is what DPS is all about."Lee Wells, Pathnet

    Why You Need Help With Your SCADA Implementation

    Implementing anSCADAsystem can seem deceptively easy - you just look on the Web,find a few vendors, compare a few features, add some configuration and you're done, right?

    The truth is, developing a SCADA system on your own is one of the riskiest things you can

    do. Here are some of the typical problems you might face if you don't get expert advicewhen you're designing your system:

    1. Implementation time is drawn out: It's going to take longer than you think. Network

    monitoring is a highly technical subject, and you have a lot to learn if you want a successfulimplementation. And anytime you are trying to do something you've never done before, you

    are bound to make mistakes - mistakes that extend your time and your budget beyond theirlimits.

    2. Resources are misused: If you're not fully informed about your options for systems

    integration, you may replace equipment that could have been integrated into your new

    system. Rushing into a systemwide replacement when you could have integrated can costyou hundreds of thousands of dollars.

    3. Opportunities are missed: If you install a new SCADA system today, you'recommitting your company to that system for as long as 10 to 15 years. Many companies

    design what they think is a state-of-the-art SCADA system - and then find that theirtechnology is actually a generation behind.