SCADA Final

A major advantage to SCADA is it's simplicity and ease of understanding and implementing.

True
False

False

SCADA can only occur over short distances.

True
False

False

SCADA systems can have both digital and analog signals for control and data collection.

True
False

True

"RTU" is an acronym for Remote Terminal Unit.

True
False

True

The RTU is a device that is used to display data collected.

True
False

False

Key features for SCADA software include user interface, graphic displays and alarming capability.

True
False

True

A Programmable Logic Controller must be used as a RTU in a SCADA application.

True
False

False

Jacob Nielsen's 10 rules of UI Usability for UI design are required for all UI designs in the SCADA market.

True
False

False

It is a better practice to use proprietary SCADA software in a system.

True
False

False

Field level instrumentation and control devices can consist of digital & analog sensors, motor controllers, & VFD's.

True
False

True

One major advantage of SCADA is that system problems can be detected and corrected immediately.

True
False

True

Alarming is not a requirement of SCADA systems.

True
False

False

The Master Station includes nothing more than a single PLC.

True
False

False

The main function of the RTU is collect data, convert it to digital format & __________.

Store it on the RTU
Analyze the data
Transmit data to the master station
Display all data

Transmit data to the master station

"Feedback" refers to which of the following when using a HMI to interface with a control system?

PID loop configuration
Audio signals when something happens in the system
It should be obvious when a control on a screen has been used
None of the above

It should be obvious when a control on a screen has been used

Large SCADA systems may require which item below to gather data from a region or group of RTU's?

Master 2
Submaster
Intermediate RTU
Middle Master

Submaster

When designing any HMI or user interface, visibility is a critical factor in the design. What does visibility mean when designing a HMI?

It should be obvious what the control is used for.
All objects should be correctly colored and labeled.
Objects should be big.
Large text should be used so it is easy to read.

It should be obvious what the control is used for.

A typical SCADA system consists of four main components. Which one below is NOT one of the components?

Field Level Instrumentation
Communication System
Tag Database
Master Station

Tag Database

The term "Affordance" refers to which of the following?

Cost of system within budget
It should be clear and obvious how a particular control is used.
Any HMI object should be identified in the tag database.
Time restraints of development.

It should be clear and obvious how a particular control is used.

The HMI can be used for which of the following?

Motor Controller
Program the PLC
Communicate data to the master
Display data graphically and text based

Display data graphically and text based

A major advantage of using a modern PLC for the RTU is _______________.

Easy to understand
Multiple Communication ports
Expandable
All of the above

All of the above

A major disadvantage when implementing SCADA systems is _________.

Data can be displayed in multiple locations
Many sensors can be used
System can be very complicated
Digital and analog signals

System can be very complicated

Which one below is not a disadvantage of using a RTU instead of a PLC at the RTU?

Proprietary programming
Cost
Not typically used in New England
Industry needs / protocols

Industry needs / protocols

What does RTU stand for?

Random Terminal Unit
Remote Telemetry Unit
Remote Terminal Unit
Radio Termination Unit
Both b & c
None of the above

Both b & c

What does HMI mean and how is it used in a SCADA system?

HMI means human machine interface and it is used in a SCADA system to let a operator of the system control the information they receive.

SCADA telemetry provides a path of communication from master to remote sites.

True
False

True

"DCE" stands for Data Control Ethernet.

True
False

False

A protocol is a language that uses a standard structure for devices to communicate.

True
False

True

DF1 Half Duplex protocol can be used for simultaneous bi-directional communications.

True
False

False

Increasing the gain of an antenna will result in the transmitted radio waves being more spread out and less directional.

True
False

False

The Ethernet OSI Model or "stack" consists of 11 layers.

True
False

False

The DNP3 protocol allows for data timestamping.

True
False

True

Point to Point communication can have more than two devices communicating.

True
False

False

DTE is an acronym for which of the following?

Date Time Equivalent
Data Time Ethernet
Data Terminal Equipment
None of the above

Data Terminal Equipment

Which item below is not a typical link media in a SCADA system?

Public Transmission
Wireless / Atmospheric
Blue Tooth
Dedicated Line

Blue Tooth

What does the "OSI" stand for in Ethernet OSI?

Open Systems Interconnection
Open solution interlock
Only Speed Initialization
On System Input

Open Systems Interconnection

The type of cable or feedline does not matter when designing a radio communication system.

True
False

False

The DF1 Radio Protocol allows for a unique communication advantage. Which item listed below is that advantage?

Bi-Directional Communication
HI-Speed Baud Rates
RTU report by exception
Error Checking

RTU report by exception

Doubling the gain of a radio transmission will result in which dB increase shown below?

2 dB
3dB
1 dB
4 dB

3dB

Feedline attenuation is caused by which two items shown below?

Weather and Temperature
Licensed or Unlicensed
Omni or Directional Antenna
Feedline type and frequency

Feedline type and frequency

Which frequency listed below would not require the user to obtain a license from the FCC?

300 MHz
2.4 GHz
120 Hz
400 MHz

2.4 GHz

A major disadvantage to using the Public Switched Telephone Line is _________________.

Cost effective for short data collection
Half duplex only
High error rates
Client / Server topology

High error rates

Calculate the wavelength in meters of a 250 MHz frequency. Assume the following:
Speed of light = 300,000,000 m/s

1.1991 m
3.222 m
.987 m
32 ft

1.1991 m

Point to point communication could also be referred to as ______________.

Half Duplex
Multipoint
Peer to peer
the Master Station

Peer to peer

It is possible to connect a Siemens PLC and an Allen Bradley PLC together using Ethernet and have successful data transfer with no other requirements or hardware.

True
False

False

Which type of antenna should be used at the master station?

Directional
Horizontal Polarization
Omni Directional
15 db Gain Antenna

Omni Directional

Which signal strength listed below would be considered the best? Assume 0 dB as the reference.

-100 dB
-35 dB
-21 dB
-50 dB

-21 dB

Calculate the size of a 1/2 wave antenna that will be transmitting a 300 MHz signal. Assume the speed of light to 300,000,000 m/s.

3 m
.5 m
1 m
2.3 m

.5 m

Spread Spectrum radios use a technology that can also be referred to as ____________________.

Licensed
Frequency Hopping
UHF or SHF
Line of Sight

Frequency Hopping

VHF operates between what frequencies below?

30 MHz - 300 MHz
15 Hz - 25 Hz
3 GHz - 30 Ghz
300 MHz - 1 GHz

30 MHz - 300 MHz

What is SCADA?

The combination of telemetry and data acquisition. Telemetry or method of communicating can be done in many ways and can short or very long distances. SCADA encompasses the collecting of information, transferring it back to the central site, carrying out the necessary analysis and control and then displaying that information on a number of operator screens or displays.

Advantages of SCADA system?

The computer can store and record large amounts of data
Data can be displayed in multiple ways
Graphically, Text Based
Thousands of sensors over a wide area can be connected to the system
Many data types can be collected from remote sites, digital, analog from very long distances

Disadvantages of SCADA systems?

System can be complicated
Thousands of I/O points
Hundreds of "screens" for the HMI
Different operating skills required, system analyst, programmers
Potentially large amounts of wiring, but we will discuss ways to reduce

What are the main components of a SCADA system?

Field Level Instrumentation and Control Devices
Remote Terminal Units
Communication System
The Master Station

What does Field Level instrumentation and control devices contain?

Analog and Digital sensors, motor starters, VFD

What do RTUs do?

Collect field data and send it back to the master station. Digitize and packetize these signals so they can transmitted over long distances

What does a Communication System do and what are some systems?

Must provide accurate and timely data. Can be done many ways; wire, fiber, radio, telephone line, cellular networks, microwave and satellite.

What does the Master Station do?

Gather data from RTU and provide operator interface for display of information and control of remote sites (RTU)

What does RTU mean?

Remote Terminal Unit or Remote Telemetry Unit

What do analog sensors check?

Flow, Pressure, Level

What do digital sensors check?

Overloads, pressure switches, generator status, level

What are Smart Sensors?

Analog sensor and digital transmitter all in one

What is required at a remote site?

Power
Communications network; wired or wireless, radio
Building / enclosures
Control Devices; pumps, fans, lights, valves etc...
Sensing devices; level, pressure, speed, temp etc....
Operator Interface
Local Alarming

Places where RTUs are used?

○Waste water systems
RTU's are located @ Lift Stations, Remote Pump Stations
○Energy Production
RTU's are located @ remote transformers, switching stations
○Natural Gas delivery
RTU's located throughout locale for pressures etc...
○Buildings / Facilities
RTU's located for HVAC, Refrigeration, Lighting and Security
○Manufacturing
RTU's located for inventory, monitor process
○Mass Transit
RTU's are located for regulation of subways, trains, busses; track and locate
○Traffic Signals / Control
RTU's located throughout city to control traffic and detect failed signals

What is the differences of RTUs and PLCs?(Advantages and Disadvantages)

RTU Advantages:
○Suitable for larger systems
○Multiple communication & protocol options
○Industrial Rating (ex. Temp ratings greater than PLC)
○Firmware designed specifically for task
○Industry Specific choices (Emerson Pump Brochure)

RTU Disadvantages:
Typically Proprietary, programming etc...
Cost
Different hardware from widely used PLC (especially in N.E.)

PLC Advantages:
Simple Ladder programming or IEC 61131-3 programming; SFC, FBD, ST
Newer models of PLC designed for SCADA; ex. MicroLogix 1400 & 1100
Multiple communication ports
Not proprietary
Compact size
Ease of design. Install, troubleshooting Expandable
Reliable
Familiarity of hardware / software

PLC Disadvantages:
Certain models of PLC lacking some features that RTU may offer
○Protocols on communication ports
○Data logging features
○Display options (however, adding a graphic terminal solves problem)

What does the Master Station include?

PCs - Operator Stations, Data Servers
PLCs/RTUs - Local control at main facility
Network(s) - Typically Ethernet, but can be more

What are the Master Station's functions?

Establishment of communications
*Configure each RTU
*Initialize RTU with input/output parameters, set points
*Download control and data acquisition programs to RTU
Operation of Communication Link
*If a master/slave arrangement; poll each RTU for data read and write
*Log alarms and events to hard disk
*Link different RTU data if necessary
Diagnostics
*Provide accurate, timely diagnostic information of RTU failure
*Predict potential problems, like data overloads

What specifics does the Master Station offer?

Operator interface to display RTU status and enable operator control
Data logging from RTU's
Alarming of data from RTU's
Obtain field data periodically from RTU or sub-master(for control of specific regions at main facility
Sub-Master

What are some master station software key features?

User Interface
Graphic Display
Alarms
Trends
RTU Interface
Scalable
Access to Data
Database
Networking
Fault Tolerance & Redundancy
Client/Server Distributed Processing

What are the Master Station's Topologies?

Centralized - Single PC performs all operations
Distributed - Multiple PCs for different processes
Client/Server - Specific servers and clients performing specific tasks (Most used)

What are two things you want in a Master Station's Topology?

Server redundancy options and system expandability

What is point to point topology?

Communication link between two stations only, either station can initiate communication or one station can be master

What is point to multipoint topology?

Communication link among three or more stations with one being master, master station is communication arbitrator and controls when other stations can communicate

What is multipoint to multipoint topology?

Link among three or more stations, no master station, any station can communicate at any time

What are the two transmission modes?

Half Duplex and Full Duplex

What is half duplex?

Information sent in one direction at a time

Which topology uses half duplex?

Point to Multipoint

What is full duplex?

Information sent in both directions at same time

Which topology uses full duplex?

Point to Point

What transmission mode does Multipoint to multipoint use?

Both

What are the 3 types of link media?

Public Transmission
Wireless/Atmospheric
Dedicated Line

Examples of Public Transmissions?

PSTN - Public switched telephone line - Uses standard telephone modem
PLL - Private leased line - Dedicated analog line for permanent connection 24 hrs a day
DDS - Digital Data Services - Special dedicated digital line provided by phone company
ISP - Internet Service Provider - High speed broadband Ethernet connection

Examples of Wireless / Atmospheric?

Microwave radio
VHF/UHF radio
Satellite
Cellular

Examples of Dedicated Line?

Dedicated wire
Power line

If your transmission mode is bidirectional but one direction at a time what type of protocol would you use?

DF1 half-duplex or DNP3

If your transmission mode is simultaneously bidirectional what type of protocol would you use?

DF1 full-duplex or DNP3

If your transmission mode is peer-to-peer what type of protocol would you use?

DF1 radio modem or EtherNet/IP

What is radio propagation?

The behavior of radio waves when they are transmitted, or propagated from one point on the Earth to another

What is VHF?

Very High Frequency 30 to 300MHz

What is UHF?

Ultra High frequency band 300MHz-3GHZ

What is SHF or microwave?

Super High Frequency, 3GHz to 30 GHz

What are some common licensed telemetry frequencies?

72 to 76 MHz
150 to 174 MHz
400 to 420 MHz
450 to 470 MHz
900 MHz

What are some common unlicensed frequencies?

900 MHz spread spectrum
2400 MHz spread spectrum
5000 MHz spread spectrum

What do you measure Antenna Gain in?

Decibels, doubles every 3 dB

What happens as Antenna Gain increases?

The Antenna Pattern becomes more directional

What happens with an Omni-Directional antenna?

Radiates RF energy in all directions from antenna

What happens with a Directional antenna?

Compresses RF energy in one direction

What is used as feedline for antennas?

Cables

What is CIP?

Common Industrial Protocol

Layer 3 is responsible for the switching and routing technologies, creating logical paths for transmitting data from node to node.

True
False

True