1. PLC Building Automation
and Control Systems
SSET 295 Internship Project
Tags: Automation,BAS, BuildingAutomationSystems,Control,
Control Panels,Critical Infrastructure,EnergyEfficiency,Fire
Safety,LadderLogic,LightingSystems,PLCs,PLCLogix,Power
Management,Programmable LogicControllers,SecuritySystems,
Smart Buildings,Sustainability.
Chad Ryan Weiss
6/17/2016

2. 1
Abstract:
Imagine abuildingthatcan respondto emergency situations. Eventslike Chernobyl,Fukushimaand
Three-Mile Islandmaynothave beensocostlyif automatedprocessesandcontrol systemshadbeen
properlyimplemented. Furthermore,imagine abuildingthatcanincrease itsoverall energyefficiency
usingpredictive analyticswithautomation andcontrol systems;humancivilizationwouldbe takingone
stepcloserto achievingsustainability thuspromotinglongevityforourplanetandall of itsinhabitants.
Thisdocumentprovidesaside-by-sidecomparison of critical infrastructure bothlackingandcontaining
automationandcontrol systems. Finally,thisreportconcludes byprovidingan implementation example
of a PLC (programmable logiccontroller) forvarioussubsystems. Usingladderlogicwiththe PLCLogix
software, the case studyseeks toaddressthe sustainability andemergencyresponseissues plaguing
critical infrastructure whichlacks bothbuildingautomation andPLCcontrol systems.

3. 2
Table of Contents
I. Introduction 4
A. Smart Buildings 4
B. Critical Infrastructure 4
C. SubsystemOverview 4
1. Accessand Security 5
2. CommunicationSystems 5
3. ElevatorsandEscalators 5
4. Fire Safety 5
5. HVAC 6
6. Lighting 6
7. PowerandEnergy 6
8. ManufacturingEquipment 6
9. Water andPlumbing 6
II.Programmable LogicControllers 7
A. LightingSubsystem 7
B. HVACSubsystem 11
C. Accessand SecuritySubsystems 17
D. CommunicationsSubsystem 19
E. Water,PlumbingandFire SafetySubsystems 20
III.Conclusion 23
IV.References 25

4. 3
List of Tables and Figures
Table 1: LightingSubsystemI/OMapping
Table 2: HVACSubsystemI/OMapping
Table 3: AccessControl SubsystemI/OMapping
Table 4: CommunicationSubsystemI/OMapping
Table 5: Fire Safety,WaterandPlumbingI/OMapping
Figure 1: PLCLogix I/Orack
Figure 2: Initial Conditions –Master SwitchON
Figure 3: Manual Override Illustration
Figure 4: Fault DetectionIllustration
Figure 5: Gas PoweredHeatingUnit
Figure 6: CondensingCoolingUnit
Figure 7: HVAC PLCI/O Interface - Initial Conditions
Figure 8: HVAC PLCI/O Interface – Furnace ON
Figure 9: HVAC PLCI/O Interface – CondensingUnitON
Figure 10: Heaterand CoolerON
Figure 11: HeatingInspection
Figure 12: CoolingInspection
Figure 13: HeatingandCoolingInspection
Figure 14: ElectronicKeypadLock
Figure 15: AccessControl Subsystem- Initial Conditions
Figure 16: AccessControl Subsystem - Unlocked
Figure 17: CommunicationSubsystemI/ORack - FSO
Figure 18: CommunicationSubsystemI/ORack - RF
Figure 19: Water DispensingNozzle
Figure 20: IonizingFire Detector
Figure 21: Fire SafetySubsystemI/Orack
Figure 22: Fire SafetySimulation - Fire Detected

5. 4
I. Introduction
A. Smart Buildings
Everysmart buildinghasacontrol room, especiallybuildingslike airports,hospitals,prisonsandpower
plants. These control roomsallowoperatorstomonitorandmanage subsystems remotelyand
sometimesautomatically. Subsystemslike energy,water, plumbing,HVAC,lighting,fire safety,access
and security,elevators,communication,robotsandpower equipmentall requirespecialattention,
because failure in anyone of these subsystemscouldspell disasterunderthe wrongsetof
circumstances. Althougheachsubsystemhasvariable importance,failureisintolerable because
somethingassimple as waterunexpectedly shuttingoff inabuildingcanhave consequencesranging
fromminordiscomforttonuclearmeltdown. The importance of eachsubsystemisentirelydependent
on the type of critical infrastructure that isbeingsupporting.
B. Critical Infrastructure
Critical infrastructurereferstothe infrastructure whoseassets,systemsandnetworks are consideredso
importantto the UnitedStates thattheirdysfunction would bringforthdire consequences fornational
economicsecurity aswell as national publicsafetyorhealth concerns[1]. Accordingtothe United
StatesDepartmentof HomelandSecurity,there are 16 differentcritical infrastructuresincludingthe
following:
Nearlyall of the sectorslistedhere,aside fromtransportationsystems,relymostlyonbuildingsor
superstructuresforshelter. Hence,the subsystems comprisingnearly100% of all critical infrastructures
inthe UnitedStatesare subsystemsrelatedtocommercial andindustrial buildings. Formore oncritical
infrastructures,referto[1].
C. SubsystemOverview
Withoutthe implementationof automationandcontrol systemssome of the subsystemstalkedabout
previously are prone tocatastrophicfailure. The followingsection providesinsighttohow each
subsystemcanbe improvedbyimplementingautomationandcontrols. Furthermore,some sections
provide acomparisonbetweensystemshavingautomationandcontrols tosystemslackingautomation
and controls. Here isa listof the subsystems previousmentioned:
 Dams
 Defense industrial bases
 Emergencyservicessector
 Energysector
 Informationtechnologysectors
 Nuclearreactors,materialsandwaste
 Transportationsystems sectors
 Water andwastewatersystems
 Financial servicessector
 Foodand agriculture
 Governmentfacilities sector
 Healthcare andpublichealthsectors
 Chemical sector
 Commercial facilitiessector
 Communicationssector
 Critical manufacturingsector

6. 5
1. Access and Security
Since the year2013, there have beenover180 school shootings inthe UnitedStates;hence,accessand
securityisa top concernwhenitcomesto establishingsubsystemswithincritical infrastructure. A good
securitysystemhasbothactive andpassive sensorsusedforremote sensing. Furthermore,automated
alarmingsystems aswell asphysical barriershelpcontribute tothe overall effectivenessof the security
systeminplay. Whenhumansencounterdanger,ourfirstresponse isautomatic,i.e.eitherfightor
flight. Witha properautomationandcontrol system, accessand securitysubsystemsinbuildings may
be able to assistindeterringfuture school shootings,bankrobberies, terroristattacks orsimilaractsof
crime and terror.
2. CommunicationSystems
Aside fromaccessand security,abuilding’scommunication systemisatop subsystemconsideration
because communicationishalf of whatmakes abuildingsmart,the otherhalf beingautomationand
control. Integratingautomationandcontrol techniquesin communicationsystemswithinbuildings may
allowformore robustinternal andexternal formsof communication. Forexample,manual orautomatic
control of the methodsof communicationusedcouldincrease buildingenergyefficiencywhileenabling
a widerrange of possibilitieswhenitcomestointernal orexternal buildingcommunications.
Furthermore,implementingautomationandcontrolsin communicationsystems couldhelp technicians
or buildingoccupantstroubleshootthe systemsduringtimesof unexpectedfailure. Thistopicis
discussedinfurtherdetail inthe PLCsolutioncase study. See Ref [2] or the ZigBee Alliance/BACnet.
3. Elevators and Escalators
Althoughthissubsystemhasnorelevance in singlestorybuildings,itisalmostalwaysreasonforconcern
inbuildingsof twoormore stories. Hospitals,schools,banks,mallsandlibrariesall have elevators or
escalators toaccommodate those who are handicappedorthose whohave beendisabledinsome way
shape or form. Elevatorsor escalatorswithoutautomationorcontrol systemsare notonlydangerous
but alsowasteful inregardstopower andenergy consumption. Inthe case that one or more floors
withinabuildingare onfire,allowingthese systemstoremainoperational isnotonlystupidbutit could
leadto unnecessary lossof life. Furthermore, leavingescalatorsoncontinuously isaproblemdue tothe
fact that cost will goup, energyefficiency will godownand emergency responseorroutine maintenance
will become negligible.
4. Fire Safety
Anotherimportantsubsystem,thatwhichprotectsthe building’sinhabitants,isthe fire safetysystem.
Withoutautomationandcontrol,response toanemergencysituationsuchasa fire wouldbe much
slowerthanif there were sensorsandautomaticproceduresinvolved. Peoplewouldhave torunaround
tryingto findthe fire extinguisherthenrunall the wayback to the fire,whichhasspreaduncontrollably
by that point. Implementingautomationandcontrol featurestoalreadyexistingfire safetysystems
couldnot onlyreactinstantlytofire;moreover,manual operationsof the fire safetysystemcomponents
like the waterlinescouldpreventwastedwaterincasesof false alarm.

7. 6
5. HVAC
HVACor heating,ventilationandairconditioning systems constitute one of the mostimportant
subsystemsabuildingcould have formanydifferenttypesof critical infrastructure. Chemical and
nuclearfacilitiesuse themtoexhauststeamandtoxicchemicals; furthermore, heating, ventilation and
coolingextendsnotonlytobuildingsbutalsotothe humanbodyand motorizedvehicles. The human
bodyneedstoventall of the carbon dioxide thatbuildsupovertime otherwise hypercapnia,a.k.a.CO2
poisoningcouldhappen. Mostcritical infrastructure HVACsystemsplayahuge role inmaintaining
essential processes. Forexample,HVACsystems keepdatawarehouseequipment cool enough to
ensure thatprocessorsdon’toverheatwhichwouldcompromisefunctionality. Heating,ventilationand
air conditioningwithoutautomation orcontrol wouldmake itimpossibletoholdcertaininternal
buildingconditionssuchastemperature,pressure orhumidity.
6. Lighting
Lightingwithoutautomationorcontrol systemsmake foraveryinefficientsystem. Implementingan
automationsettingcouldreduce the amountof energyusedwhennoone isina roomthus reducing
wastedenergy. Also,addingacontrol systemtolightingandloadsmayenable buildingoperatorsto
detectunexpected burn-outs,shorts,open-circuitsorfaults.
7. Power and Energy
Thissubsystemreferstothe powergenerationandpowerdistributionsubsystems. Powerandenergy,
beingthe backbone of the entire superstructure,requiresimmense automationandcontrol techniques
to ensure nothingcanthwarttheirabilitytoproduce andsupplypowertothe buildingandall of its
critical features. Inthe case of a lightningstrike,hurricaneorsome othernatural disaster,power
systemscouldbecome compromisedthuscompromisinganentire buildingorso. Eventslike the New
York Blackouta couple of yearsago leftthousandsof people freezinginthe wintercoldweatherfor
days. With properimplementationof automationandcontrol systems,troubleshootingmaynothave
takenso longto fix thussavingmanyfromneedlesssuffering.
8. Manufacturing Equipment
For industrial plantsormanufacturingfacilities,industrial powerequipmentcanbe verydemandingon
energyandalsohazardousto the inhabitantsof thatbuilding. If automationandcontrol systemsare
obsolete withinthesesystemsrobotscouldspinout of control or breakdown. Not toolongago, a robot
tooka man’slife ata VolkswagenfacilityinGermany forunexplainedreasons. These typesof incidents
can be reducedtoa minimumwithoutcompromisingproductivitybyaddingsimple automationand
control featurestothe alreadyexistingsystems. Furthermore,one mightevenbe able tosave money
by implementingautomationandcontrol techniques.
9. Water and Plumbing
Water andplumbingmightseemtrivialbutthere are manythingsrelyingonthese subsystems.
Hydraulics,HVACsystemsandhumansare some of the few persons,placesorthingsthatrelyon this

8. 7
absolutelycritical subsystem,whichiswhyitisimportantto know all the detailsasto how flow is
currentlybeingcontrolled. Furthermore,itisnecessarytoenactprecisionprocedural protocol
executioninresponse toemergencysituations. Eventslike TMI,FukushimaandChernobyl couldhave
possibly been avoidedif everysubsystem, includingwaterandplumbing,hadbeenworkingproperly.
II. PLC Programs
A. Lighting Subsystem
A buildinghasfourroomswithfourlightsperroom.
Table 1: Lighting Subsystem I/O Mapping
Slot 1 Slot 2 Slot 3 Slot 4
Master Switch R1L1_POWER MO_R1L1 R1L1_FAULT
R1L2_POWER MO_R1L2 R1L2_FAULT
R1L3_POWER MO_R1L3 R1L3_FAULT
R1L4_POWER MO_R1L4 R1L4_FAULT
R2L1_POWER MO_R2L1 R2L1_FAULT
R2L2_POWER MO_R2L2 R2L2_FAULT
R2L3_POWER MO_R2L3 R2L3_FAULT
R2L4_POWER MO_R2L4 R2L4_FAULT
R3L1_POWER MO_R3L1 R3L1_FAULT
R3L2_POWER MO_R3L2 R3L2_FAULT
R3L3_POWER MO_R3L3 R3L3_FAULT
R3L4_POWER MO_R3L4 R3L4_FAULT
R4L1_POWER MO_R4L1 R4L1_FAULT
R4L2_POWER MO_R4L2 R4L2_FAULT
R4L3_POWER MO_R4L3 R4L3_FAULT
R4L4_POWER MO_R4L4 R4L4_FAULT
Input Output Input Output
Input1 isthe Master Switch;it has twoconditions:
𝑀𝑎𝑠𝑡𝑒𝑟 𝑆𝑤𝑖𝑡𝑐ℎ = {
1 𝐸𝑛𝑎𝑏𝑙𝑒 𝐶𝑜𝑛𝑡𝑟𝑜𝑙 𝑃𝑎𝑛𝑒𝑙
0 𝐾𝑖𝑙𝑙 𝑆𝑤𝑖𝑡𝑐ℎ
The 1 signifiesthatthe Master Switchhasbeenturned“ON”whereasthe 0 representsthe Master
Switchwhenitisturned“OFF”. Whenthe Master Switch has a bitvalue of 1, the program will execute
rung zeroof the mainroutine thusjumpingtothe lightingsubroutine. Onthe contrary, whenthe
Master Switchhas a bitvalue of 0, the programwill execute rungone;hence,disablingall system
input/outputfunctionality. Furthermore,the systemcan be resetuponexecutionof the Kill-Switch
operation. Thisisto make troubleshootingeasierandresponse toemergencysituationsfaster.
UtilizingPLCLogix andthe I/Ointerface,the PLCcontrol panel supportsupto16 lights. Inthisscenario,
a buildinghasfourroomsor floorswithfourlightsperfloor/room. The lightingsubsystemMaster

9. 8
Switchhas the abilitytocut all powertothe building’slightingsubsystems. Furthermore,the PLC
control panel wasdesignedtoallowuserstomanuallycontrol eachlightspecificallyaccordingtothe I/O
mappingof the PLC program and control panel. See Table 1above.
The I/O mappingseeninTable 1 correspondsto the PLCLogix I/Orack or interface. Fig.1 shownbelow
presentsthe layoutof PLCLogix I/Orack.
Figure 1: PLCLogix I/O Rack
ReferringtoFig.1, the discrete I/Ointerface allows forsupervisedandunsupervisedcontrol of the
building’slightingsubsystem. Slot1,input00 is reservedforthe MasterSwitch. The usercan enable or
disable the control panel/buildinglightingsubsystembyopeningorclosingthe MasterSwitchcircuit.
Initially,whenthe MasterSwitchisturnedON,the building’slightsall turnoninthe orderspecifiedby
the PLC ladderlogic. Whenthe Master SwitchisOFF andhence,the control panel andbuildinglighting
subsystemsare deactivated,users nolongerhave anycontrol overanypart of this particularsubsystem
and control panel.
Table 1 slot2, correspondingtoslot2 data entries fromthe discrete I/Ointerface showninFig.1 reads,
R1L1_POWER. This standsfor roomone (R1) lightone (L1) powerindicator. The nextentryreads
R1L2_POWER whichstandsfor room one (R1) lighttwo(L2) powerindicator,etc... Forthisscenario,the
buildinghasfourroomswithfourlightsperroom. In otherscenarios,abuildingmayhave fourfloors
withfouroverheadlightsperfloor. All canbe changedaccordingly,dependingonthe situation, from

10. 9
withinthe PLCprogram. Fromthe PLCLogix discrete I/Ointerface,all of the dataentrieslocatedinslot2
are reserved forthe statusof each individual lightingfixture regardingpower. Inotherwords, this
columnindicateswhetherthe lightisON orOFF. Thisisshownrather clearlyfromthe I/Orack. When
an entrylightsup,thismeansthe lightisON,whenthe entryisnot litup,thismeansthe lightisOFF.
Fig.2 showsthe I/Orack whenall lightsinthe buildingare turnedonrightafteractivatingthe Master
Switch. See Fig.2 below.
The Master Switchoccupyingslot1 data entry00 has the powertoenable ordisable the entire
building’slightingsubsystemandcontrol panel. Sometimes however, itisnecessarytokeepall other
lightsonwhile troubleshootingorrewiringanotherlight. Hence,slot3entries00 through15 are
dedicated tomanual override switchesfor eachlightrespectively. Togglingtheseswitchesturnsthe
lightsOFFand ON. See Fig.3 belowfor anillustration.
Figure 3: Manual Override IllustrationFigure 2: Initial Conditions - Master Switch ON

11. 10
The fourthand final columnof the I/Orack isusedas a faultdetectionindicator. These outputswillonly
activate if the system,foranyreason,shouldfail undernormal operatingcircumstances. Inreal world
situations,PLCcontrollerscontainI/Omodulesthatcansupportcountless variationsof digital and
analogsensingequipmentthusallowingforsophisticatedfaultdetectiontechniques. However,forthe
purposesof thisproject,asimulationwasmade toillustrate how the PLCprogramrespondsto detected
faults.
For the lightingsubsystem,thissimulationusesaseriesof timersandcountersandmultipliersto
effectivelycreate afaultinthe system. Everyso often,the lightoccupyingdataentries 03,goesinto
arrest andunexpectedlyshutsoff. Althoughthe source of errorisunknown,operatorsare able to
detectthat thislighthas “effectivelyfailed”due tothe faultindicatoroutput statusinslot4 on the
discrete I/Ointerface (i.e.slot4). See Fig.4 below foranillustrationof faultdetection.
Figure 4: Fault Detection Illustration
If undernormal operatingcircumstancesa
lightshouldfail,the faultdetection
indicatorwill appearinslot4.
Then,if the lightwasnormallyON before
the fault,operatorscan manuallyoverride
the systembyactivatingthe corresponding
‘flipswitch’locatedinslot3thus cutting
powerto the lighttobe examined.
(All flipswitcheshave beenplacedinseries
withtheircorrespondinglightingfixturesas
to create a convenientergonomicdesign
for simplicity’ssake).
Note:
ReferringtoTable 1, Slot3 hasdata entries
entitled‘MO_R1L1,MO_R1L2…’. MO
simplystandsfor“manual override”and
the meaningof R1L1, R1L2, etc… have
alreadybeendiscussed. Furthermore,Slot
4 has data entriesentitled‘R1L1_FAULT
and R1L2_FAULT’, etc… Thiswasmeantto
be self-explanatoryyetmerelyresembles
the indicationstatusof whetherafaulthas
or has not beendetectedforagiven
lightingfixture withinthe building.

12. 11
The PLC program is ladderlogicbasedandconsistsof two routines,i.e.the mainroutine(whichcontrols
the control panel) andthe building’slightingsubroutine. Originally,the building’slightingsubsystem
was remotelyuncontrollableandabsolutelyunsupervised. This PLCprogram fixesbothof those
problems. Itisdone by providingremote control capabilities tothe building’ssubsystem aswell asfault
detection techniquesincase of an unexpectedlightingfailure. See AppendixA forthe PLC Program.
B. HVAC Subsystem
A typical HVACsystemconsistsof afurnace,heatexchanger,evaporatorcoil,condensingunit,
refrigerantlines, thermostat,ductsandvents. Fromthese 8 basiccomponents,the furnace,heat
exchanger,evaporatorcoil,condensingunitandrefrigerantlinesare able tobe automatedorremotely
controlledfromthe PLCcontrol panel.
StudiesshowthatimplementingPLCdevicesinbuildingHVACsystemscanleaddirectlytomore stable
environmentsaswell ashigherenergy-efficientprocesses. Thisisusuallyaccomplishedwiththe use of
PID controllerswhichcanbe implementedwithinPLCprograms. Standingforproportional integral
derivative the PIDcontrollercanhelp withthe overall rise times,settling times,andpercentovershoot
withinasystem. For HVAC,thiswouldcorrespondtothe temperature of aroom. Less energycanbe
usedif the heatingandcoolingsystemswere able tohitthe markwithoutmuch oscillationaboutthe
desiredsteadystate value. Inotherwords,the fastera systemisable toconverge uponthe final steady
state value,the more efficientitwill become.
The PLC solutionforthissubsystemwill include processcontrol switchesthatcontrol the temperature of
a room. Furthermore,the PLCprogramwill utilizeadigital heaterwhichcaneitherbe ON orOFF. This
heaterwill nothave anyanalogsignal drivingthe controlstherefore itissubjectonlytomanual
operationaswell ascertainconditionsthatenable automaticresponses.
Table 2: HVAC Subsystem I/O Mapping
Slot 1 Slot 2 Slot 3 Slot 4
Furnace Motor_1 Switch_1 Temp_Stable
Condensing_Unit Motor_2 Switch_2 Temp_Increasing
Valve_1 Switch_3 Temp_Decreasing
Motor_3 Switch_4
Motor_4 Switch_5 Heating_Inspection
Valve_2 Switch_6 Cooling_Inspection
Valve_3 Switch_7
Input Output Input Output
Table 2 above showsthe I/Omappingof the HVACsubsystem. There are twoinitial inputs,i.e.the
Furnace and the Condensing_Unitswitcheslocatedinslot1. These twoinputsare responsible forthe
heatingandcoolingof the building. WhenFurnace is closed,the heatingcomponentsof the HVAC
systemare enabled,i.e.Motor_1,Motor_2 andValve_1. Motor_1 is responsible fordrawingairfrom
the returnair duct and blowingitthroughthe furnace combustionchamberandintothe airducts.

13. 12
Motor_2 is the exhaustfanmotor,solelyresponsibleforventingthe fumesaccumulatedinthe
combustionchamber. Valve_1isthe gasvalve andis responsible forsupplyingthe furnace burnerswith
fuel forcombustion. See Fig.5belowfora visual representationof a typical heatingunit.
Figure 5: Gas Powered Heating Unit Ref. [2]

14. 13
The secondinitial input,i.e.the condensingunit,isresponsibleforcoolingthe building. When
Condensing_Unitisclosed,the coolingcomponentsactivate,i.e.Motor_3,Motor_4, Valve_2and
Valve_3. Motor_3 isresponsibleforthe condensingunitfanmotor,Motor_4 isthe compressorpump
motor,Valve_3and Valve_4are the suctionline andliquidline valves. Valves3and 4 are essentiallythe
twovalvesassociatedwiththe coolantlines. See Fig.6below forthe anatomyof a condensingunit.
Slots1 and2 correspondtothe heatingandcoolingunitsandtheirconstituentcomponents
respectively. Slot3 isusedfor controllingeachof the individual componentswithinthe heatingor
coolingunits. Switches1through7 can be manuallytriggeredtocutoff orrestore powertoone of the
componentsinsuch casesas the motor. For valves,these switcheswill eitheropenorclose a valve with
directinstruction.
Slot4 isdedicatedtothe systemstatusindicators,i.e.the temperature rising,temperaturefallingand
temperature stable statuses. Eachstatus isdiscernedbya lightturningon. Furthermore,there isthe
heatinginspectionstatuswhichmeansone of the heatingunitswitcheshave beenflippedandthere is
the coolinginspectionstatuswhichindicatesthata coolingunitswitchhasbeenflipped, mostlikelyfor
inspectionpurposes. See Table 2above forthe complete I/Omap.
Figure 6: Condensing Cooling Unit Ref. [3]

15. 14
The simulationusedforthissubsystemincludesatemperature readingof aroom. Data fromthe
simulationisstoredinthe analogtemperatureinputorslot7 data entry03 withinPLCLogix;the output
isdisplayedinslot8 data entry03 onthe I/Ointerface.
Under initial conditions,the temperature of aroomis setto 70 degreesFahrenheit. Whenthe heating
unit(i.e.the furnace) isturnedon,the temperature will begintorise andthe temperature increasing
indicatorlightwill turnon. Onthe otherhand,whenthe coolingunit,orthe condensingunit,isturned
on the temperature of the roomwill begintofall andthe temperature decreasingstatuslightwill turn
on.
It can reach temperaturesof upto120 degreesFahrenheit.
Figure 7: HVAC PLC I/O Interface - Initial Conditions
Figure 8: HVAC PLC I/O Interface - Furnace ON
Fig.7 showsthe initial conditionsof
the program. Both the furnace and
condenserare off,the temperature
stable lightisonand the temperature
readout is displaying70 degrees
Fahrenheit.
Fig.8 showsthe I/Ointerface when
the heatingunitisactivated.
Immediatelyafteractivatingthe
furnace switch,the heating
componentslightupandthe
temperature increasing statuslight
activates. Afterone secondof
activationthe temperature will start
to rise as seeninslot8 data entry03.

16. 15
It can reach temperaturesaslowas20 degreesFahrenheit.
Figure 9: HVAC PLC I/O Interface - Condensing Unit ON
Fig.9 showsthe I/Ointerface when
the coolingunitis ON. Whenthe
condensingunitisturnedon,the
coolingunitcomponentsactivated
immediatelyalongwiththe
temperature decreasingstatus
indicatorlight. Furthermore,the
temperature canbe seentobe
droppinginslot8 data entry03.
Figure 10: Heater and Cooler ON
In thisPLC program, whenboththe condensingunit
and furnace are turnedon, the temperature will
stabilize around70degrees,inactualityitfluctuates
between69and 71 degreesFahrenheit. Hence,all
three statusindicatorlights,i.e.temp_stable,
temp_increasingandtemp_decreasingare all onat
thispoint.
If for some reasonan operatordecidestoshutoff
one of the heatingunitcomponentssuchasthe gas
valve orvalve_1,the systemwill registerthe furnace
as beingshutoff and the temp_increasingstatus
lightwill turnoff automatically. Furthermore,the
heating_inspectionlightwill turnonalso. See Fig.
11 below foran illustrationof this.
Temp_Decreasing
Heating_Inspection
Figure 11: Heating Inspection

17. 16
On the contrary,if an operatordecidestoshutoff one of the coolingunitcomponents,thenthe system
will registerthe condensing_unittobe effectivelyshutoff andthe temp_decreasing statusindicatorwill
turn off and the cooling_inspectionstatusindicatorwill turnon. See Fig.12 for an illustrationof this.
If componentsfromboththe heatingandcoolingunitsare turnedoff,thenthe systemwill registerthat
bothunitsare turnedoff;therefore,the temp_stablestatusindicatorlightwillappearaswell asthe
heatingandcoolinginspectionlights. See Fig.13 foran illustrationof this.
In conclusion,the HVACPLCprogramis a digital heatingandcoolingsystem. Itisladderlogicbasedwith
onlyone mainroutine forsimplicity. All inputsandoutputsare digital. The simulationproducesone
analogoutput,i.e. the effective roomtemperature. Producedsolelybysimulation,the effective room
temperature isaportrayal of the possibilitiesof thisprogram. Inactuality,thisPLCprogramwould
utilize I/Omodulesandsensorstogive actual data. See AppendixBforthe PLCladderlogicprogram.
Figure 12: Cooling Inspection
Temp_Increasing
Cooling_Inspection
Figure 13: Heating and Cooling Inspection
Temp_Stable
Heating_Inspection
Cooling_Inspection
Here,the furnace and
condensingunitare onbut
the compressorpumpmotor
has beenshutoff for
inspection. Hence,the
coolingunitiseffectivelyshut
off and the furnace heating
unitwill dominate. The temp
increasinglightandcooling
inspectionlightappearas
showninFig.12.
Here,the furnace and
condensingunitare onbut
the compressorpumpmotor
and the exhaustfanmotor
has beenshutoff for
inspection. Hence,boththe
heatingandcoolingunitsare
effectivelyshutoff.
Therefore,the temperature
stable statusindicatoraswell
as the cooling/heating
inspectionstatuslight
indicatorshappenstobe on
as showninFig.13.

18. 17
C. Access and SecuritySubsystems
There are twodifferenttypesof securitytechniques,i.e.perimetercontrol andinternal breach.
Perimetercontrol isamethodusedtokeepintruders/perpetratorsoutof the safetyarea,whereas
internal breachsecurityisusedwhenthe intruder/perpetratorhasbreachedthe premises.
Differenttypesof critical infrastructure require differentlevelsof security. Forexample,anairport
requiresmore securitythaneducationalfacilitiesbecause theyare subjecttomore damagesif
perpetrated. Eventhoughitisdifficulttoharborthe truth that casinoshave greatersecuritycounter
measuresthanlocal highschoolsorelementary schools;realityis,statisticssaythatpremiseslike banks,
casinos,airports,prisons,powerplants,etcetera;all require higherstandards andoftentimes harbor
incrediblyexpensive securitysystems toprotecttheirassets;soexpensive that mosteducational
facilitiesare unable toaffordsuchcountermeasures.
Althoughschoolsare unlikelytoaffordgreatbigsecuritysystems,theycanaffordsome of the basicsas
to preventperimeterbreachesduringafterhours. All securitysystemsbigorsmall runonsome type of
PLC or microcontrolleralongwith24hour supervision. Thissystemwill preventperpetratorsfrom
obtainingaccesstothe safetyareathrougha PLC access control programusingPLCLogix.
The simulationcreatedusingthe PLCLogix software emulatesanelectronickeypaddoorlock. This
device isusedtokeepunwantedsuspectslackingauthorityornecessarycredentialsoutof a designated
area. For example,agunmantryingto gainaccess to a school wouldbe deniedthe opportunity to
wreakhavoc due to the perimeter“accesscontrol”systeminplace. Thatiswhat thisprogramseeksto
do.
Figure 14: Electronic Keypad Lock Ref. [4]

19. 18
Table 3: Access Control Subsystem I/O Mapping
Slot 1 Slot 2 Slot 3 Slot 4
Lock_1 Locked
One Lock_2 Unlocked
Two Lock_3
Three Lock_4
Four Lock_5
Five
Input Output Input Output
Table 3 showsthe I/Omap of the AccessControl PLCprogram. The inputsinslot1, i.e.One,Two,Three,
Four and Five representthe keypadnumbersusedtounlockthe device. Outputslocatedinslot2shows
whethereachstage hasbeenbypassed. Forthisparticularsystem, five unlockingstagesmustbe
activatedinorderto unlockthe systementirely. There are no inputsassociatedwiththisprogram
regardingslot3 and slot4 isusedto indicate whetherthe systemislockedorunlocked.
Figure 15: Access Control Subsystem - Initial Conditions
Upon initial startupthe systemislockedas
indicatedbydataentry00, slot4 seeninFig. 14.
In orderto unlockthe system, the right
combinationorsequence of numbersmustbe
pressedusingthe inputsinslot1.
Once the right combinationhasbeenpressed
withinthe giventime frames,the unlockedstatus
indicatorlightwill appearondataentry01 in slot
4. See Fig. 15 foran illustration.
Afterthe systemisunlockeditwill remain
unlockedforfive secondsbefore returntoa
lockedstate whichgivesthe userenoughtime to
turn the door handle before havingtore-enter
the necessarycredentials.
If the wrongcredentialsare entered,the system
will enteralockdownsituationforfiveseconds
before resettingthe systemautomatically.
RefertoAppendix Ctosee the PLC program
ladderlogicandto discernthe rightcombination
neededtounlockthe system.
Figure 16: Access Control Subsystem - unlocked

20. 19
Accesscontrol is a huge part of infrastructure securityandPLCsallow for promisingsecuritysystems.
One couldutilize the inputsinslot3to manuallycontrol the perimeteraccesscontrol device andwith
furtherequipment,suchasremote sensors,one couldbuildaprettysophisticatedaccesscontrol and
internal breach securitysystembyutilizingPLCs.
D. CommunicationsSubsystem
A buildinghastwomethodsof communication,i.e.byfree space optical (FSO) orradiofrequency(RF).
Table 4: Communication Subsystem I/O Mapping
Slot1 Slot2 Slot3 Slot4
Master Switch N/A FSO_Switch FSO_Communication
N/A RF_Switch RF_Communication
INPUT OUTPUT INPUT OUTPUT
Free space optical communicationismore efficient andsecure thanotherformsof communication,such
as radiofrequency andthe Internet. Hence,more buildingsare turningtoFSOtechnologiesasaprimary
methodforcommunicatingbetween one pointandanother. The onlyproblemfacingthistype of
communicationisthe atmosphericchannel throughwhichitpropagates. Intimesof heavyfog,rainor
snow,the optical source isattenuatedinthe atmosphere byatmosphericturbulence,scatteringand
absorption. For thisreason,it isnecessarytohave backupin the formof RF communicationduring
timesof inclementweather. ThisPLCprogram seekstoaddressthatissue bycreatinga hybridRF/FSO
communicationsystem.
ReferringtoTable 2, Slot1 data entry00 isreservedforthe Master Switch,whichcontrolsthe platform.
The data entrieslocatedinslot3 are reservedforthe manual override switches,thustheyare
consideredinputs. Finally,the outputstatusof the overall systemisstoredinthe dataentrieslocatedin
slot4. Furthermore,the programsimulatesbadweatherasa resultof temperaturesdropping. When
the temperature reachesacertainthresholdaround30 degrees,the systemwill automaticallyswitch
fromone form of communicationtoanother,i.e.FSOtoRF.
Figure 17: Communication Subsystem I/O Rack - FSO

21. 20
Whenthe simulatedtemperature isabove 30degreesFahrenheit,the FSOcommunicationlightswitch
will be turnedon. On the otherhand,whenthe temperature is30 degreesFahrenheitorless,the RF
lightswitchwill be on. RefertoFig.17 below foran illustrationof this.
As showninFig.16 and 17, automaticprocessescan be usedto switchmethodsof communicationto
ensure continuity.Furthermore,withmanual overrideswitchesone couldcontrol the methodof
communicationdirectly. Thismaybe useful underaspecificsetof circumstances.
E. Water,Plumbingand Fire Safety Subsystems
Everysmart buildinghasafire safetysysteminstalled. The bestwaytodetectfireswithoutdirect
supervisionisbyusingsmoke detectors. Ionizationsmoke detectorsare apopularchoice fordetecting
smoke because of theirsensitivitytoit. Theyuse a radioactive substance thatgeneratescurrentinside
the detector. If there issmoke presentinthe detector,the currentwill cease toflow andthe alarmwill
be triggered. Underthiscondition,alongwithseveral others,fire mitigationdevicessuchaswater
dispersionsystemstendtoturnonautomatically.
For thisreason,itis incrediblyimportanttohave functionalwaterandplumbingsystemsincase of fire
or otherrelatedcatastrophes. Thismayinclude core meltdownsinnuclearpowerplants. Automation
and control systemsforwater,plumbingandfire safetysubsystemscansave livesandprevent
emergenciesfromescalating. ThisPLCprogramwill create a watermanagementsystemaswell asafire
safetysystemthatutilizesautomationandcontrol practicestoensure sustainabilityandsafety.
Figure 18: Communication Subsystem I/O rack - RF

22. 21
Table 5: Fire Safety, Water and Plumbing I/O Mapping
Slot 1 Slot 2 Slot 3 Slot 4
Simulator F1R1V1 MO_SWITCH_1 F1R1V2
FLOOR_1_SWITCH F1R2V1 MO_SWITCH_2 F1R2V2
FLOOR_2_SWITCH F1R3V1 MO_SWITCH_3 F1R3V2
FLOOR_3_SWITCH F1R4V1 MO_SWITCH_4 F1R4V2
FLOOR_4_SWITCH F2R1V1 MO_SWITCH_5 F2R1V2
ALL_ON F2R2V1 MO_SWITCH_6 F2R2V2
ALL_OFF F2R3V1 MO_SWITCH_7 F2R3V2
F2R4V1 MO_SWITCH_8 F2R4V2
F3R1V1 MO_SWITCH_9 F3R1V2
F3R2V1 MO_SWITCH_10 F3R2V2
F3R3V1 MO_SWITCH_11 F3R3V2
F3R4V1 MO_SWITCH_12 F3R4V2
F4R1V1 MO_SWITCH_13 F4R1V2
F4R2V1 MO_SWITCH_14 F4R2V2
F4R3V1 MO_SWITCH_15 F4R3V2
F4R4V1 MO_SWITCH_16 F4R4V2
Input Output Input Output
Table 5 isan input/outputmapof the fire safety,waterandplumbingsubsystems. Slot1controlsthe
built-insimulationaswell asthe variouswaterdistributionsystemsforeachfloor. The outputsare
locatedinslots2 and4. Theyare simplystatus indicatorlightsthatshow whetheradevice hasbeen
turnedon;in thiscase,the devicesbeingturnedoff andonare water line valvescomingbefore and
afterthe sprinklernozzle(s).
Legend:
 F – Floor
 R – Room
 V – Valve
 MO – Manual Override
Thisbuilding,the programwasbuiltfor,consistsof fourfloorswithfourroomsperfloor. Slot3 isa
control panel usedtocontrol the waterdispersingsystems. Forexample,MO_SWITCH_1controlsthe
valveslocatedoverroomone floorone (F1R1V1and F1R1V2).
The inputslocatedinslot1 are furthercontrols. Floorcontrolsactivate anddisable the valveslocated
on floorone,two,three andfourrespectively. Slot1 alsocontainsan ‘all on’and ‘all off’switch. Lastly,
there isthe simulatorswitchwhichcontrolsthe built-insimulation,i.e.anionizingfire detector
detectingsmoke bynoticingasignificantdropof electrical currentinthe device.

23. 22
Figures19 and 20 showthe twomaindevicesusedinfire safetysystemswithinbuildings. Fig.19 shows
the waterdispensingnozzle whichisresponsibleforthwartingactive firesandFig.20 showsan ionizing
fire detectorwhichisusedindetectingthe signsof anactive fire. These twodevicesworkinharmonyto
ensure buildingsafetyagainstthreatregardingfire safety. The PLCprogram forthisbuildingsubsystem
shouldallowfora more efficient approachtohandlingbuildingfires. Byallowingformore precise
control of the water,plumbingandfire safetysystem, the situationislesslikelytoresultinloss,i.e.loss
of water,resourcesandlife.
The simulationbuiltintothisprogramruns ona 60 secondtimerthat alternatesbetweentwoscenarios,
1) an ionizingfire detectordetectssmoke and2) an ionizingfiredetectordoesnotdetectsmoke. When
no smoke isdetected,the I/OmaplooksasshowninFig.21 below.
Figure 19: Water Dispersing Nozzle Ref. [5] Figure 10: Ionizing Fire Detector Ref. [6]
Figure 11: Fire Safety Subsystem I/O Rack

24. 23
In Fig.21 slot8 data entry01, 5.0 mA of currentindicatesthatnosmoke isdisruptingthe alphaparticle
emission –stimulatedcurrentof the ionizingsmoke detector. Conversely,whenthe display reads1.0
mA whichmeansthe ionizingbeamof alphaparticleshasbeendisruptedbysmoke,thusreducingthe
currentwithinthe device. See Fig.22.
The 1.0 mA of current showninFig.22 slot8 data entry01 indicatesthatthe fire detectorhasdetected
smoke. Asshowninslots2 and4, all lightshave beenlituptoindicate the valvesleadingtothe water
distributionnozzles have beenopened. Hence waterisflowingandextinguishingthe fire inthe building.
On topof thisautomaticprocess,the PLC programutilizesdigital switchestoissue variouscontrol
responses. Suchresponsesinclude:activating/deactivatingnozzlesindividually,byfloororaltogether.
Thisis to ensure thatwaterisnot wastedinan eventsuchas a false alarmbut alsoto ensure that
actionscan be takenintothe handsof a humanintervenerwhenthe time isright. Combiningboth
automaticprocesseswithcontrol methodsissuedbydirectsupervisionwill allow forasmarterand safer
environment. See Appendix Eforthe PLC program.
Conclusion
Everysmart buildinghasautomatedprocessesinadditiontovariouscontrol systems. Inthisreportwe
introducedthe conceptof a smart buildingandhow itmightextendtovarioustypesof critical
infrastructure acrossthe UnitedStates. Upondoingso, we identifiednine majorsubsystemswithin
Figure 12: Fire Safety Simulation - Fire Detected

25. 24
smart buildings. Outof these nine,we addressedfivebycreatingPLCprogramsto enhance subsystems
lackingautomationandcontrol processes,i.e.Lighting,HVAC,AccessandSecurity,Communicationsand
Fire Safety.
While introducingthe lightingsubsystem, we were abletodistinguishwhatcontrolsmayhelpincrease
sustainabilityandemergencyresponse times. Thiswasachievedbycreatingacontrol panel thatwould
allowforfaultdetectionandmanual overridecapabilities. Bybeingable tocontrol the lightingsystem
withinabuildingremotelycreates notonly aconvenience topeoplebuta practical applicationaswell.
For the HVACsubsystem,we analyzedHVACsystemcomponentsinordertofindareasthatmay allow
for controlsimplementation. Upondoingsowe discoveredthatthe heatingandcondensing(cooling)
unitseachhave fans (motors) andvalvesthatare critical to the functionalityof the units. Therefore,
controlswere implementedtoeachof these components. Furthermore,the PLCprogramthat was built
simulatesadigital heater/coolerwitharange from20 degreesFahrenheitto 120 degreesFahrenheit. It
alsohas a temperature stabilizationsettingwhichhoversaround70 degreesFahrenheit.
The third smartbuildingsubsystemwasthe accessandsecuritysubsystem. Forthissubsystemwe built
an electronicperimeteraccesscontrol securitylock. Usingonlytimersand conditions,the lockonly
openstothose whoknowthe correct sequence andforthose whocanexecute thissequence withina
giventimeframe.
Followingthe accessandsecuritysubsystemwasthe communicationssubsystem. The PLCprogram
constructedforthissubsystemwasnotfor internal buildingcommunicationbutforexternal building
communication. Essentially,the PLCprogramsimulatesanautomaticswitchinghybridRF/FSO
communicationsystemgiventhe atmosphericconditionsasaninput.
Lastlywas the fire safetywaterandplumbingsubsystems;here we constructedasimulationthatranon
a 60 secondtimeralternatingbetweentimesof fire andtimeswithout. The PLCprogram wasbuiltto
respondtothe built-insimulationbyissuingcommandsautomatically. Furthermore,the systemwas
builttoresponddirectlytouserinputmeaningthat,underdirectsupervision,the systemcouldbe
controlledatwill.
By creatingPLC programsfor eachindividual buildingsubsystem,we create smarterbuildings. The
conceptof a safer,smarterbuildingwasthe drivingforce behindtheseprojects. Furthermore, utilizing
PLCs wasa greatway to gaininsightintothe worldof programmable logiccontrollersandhow effective
they can be in makingourworlda saferandsmarter place tolive in.

26. 25
References
[1] Critical Infrastructure Sectors
https://www.dhs.gov/critical-infrastructure-sectors
[2] Coolingunit
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=isch&sa=X&ved=0ahUKEwj-kd65j_vMAhWly4MKHW_fD4UQ_AUIBygB#imgrc=pl-hCZdwfG7tSM%3A
[3] Heatingunit
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KEwjvxJv9maDNAhVS72MKHa_kD8gQjRwIBw&url=http%3A%2F%2Findore.all.biz%2Fwater-sprinkler-
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KEwjNke7Dm6DNAhVT1GMKHcDOCtsQjRwIBw&url=http%3A%2F%2Fwww.cableorganizer.com%2Fsmo
ke-detectors%2F&psig=AFQjCNFxjfliyPZSHFSaVHlxI1gWNKWavQ&ust=1465742780592482