Specifications


TR16andTZ16fromResidentialControlSystemsInc.(RCS)
TheRCSTR16thermostatconsists oftwoparts,thewalldisplayunitontheleft
andtheHVACcontrolunit.Thewalldisplayunithasasimpleuserinterface
withsetpointup/down,mode,andfanbuttons.TheTR16offersRS‐485c
usingASCIIcommandsthatareverywelldocumented.Thiscontrollogicisv
similartothatofthecustom‐designedthermostatfromlastyear,makingfor
possiblyeasiercomponentintegration.WhiletheTR16doeshavestand‐alone
operation,anyschedulingwouldhavetobedonewiththehomecontrolserve
Inaddition,thethermostatcomeswitha12VDCpowersupply,sowewould
eitherneedadedicatedwalloutlet,orwecouldcustombuildacircuitto
24VACcommonwire.Thiswouldprimarilyinvolvea12Vregulatorandsome
filtercapacitors.Thecostofthethermostatis$234fromwww.smarthome.com.AnRS‐485to
232converterforaPCisinthe$80‐100range.
ontrol
ery

r.
convertthevoltagefrom
DB‐9RS‐
TheTZ16isthesamethermostatwithanadditionalZ‐Waveadapterallowingthethermostatto
communicatewirelesslyoverradiofrequencies.Tointegratethiswiththehomecontrolserver,aZ‐
WaveUSBorRS‐232adapterisnecessary.TheTZ16costs$270andtheUSBadaptercosts$60from
smarthome.com.
Source:http://www.resconsys.com/products/stats/serial.htm
and
http://www.resconsys.com/products/stats/zwave.htm


Aprilaire8870
Themodel8870communicatingthermostatfromAprilaireoffers
communicationaswellasstand‐alonefunctionality.Theunittotheleft
hasincrease/decreasesetpointbuttonsaswellasmode,fan,andmenu
controlbuttonsunderneath theoutercover.Ofthethreecandidate
thermostats,the8870hasthemostcomplicateduserinterface.In
addition,communicationsetupisnotclearlydocumented.Installation
guidesindicatethatseveralothercomponentsareneededforoperation:
anAprilaire8818distributionpaneltoprovidepower,an8811protocol
S‐232,andan882724‐VACtransformer.Whileallthesecomponents
mayaddacertainamountofreliability,itamountstoaquestionablenumberofcomponentsfora
HVACunit.Thethermostatcosts$244,thedistributionpanel is $ 100,theprotocoladapteris$110,and
thetransformeris$20,addinguptothemostexpensivecommercialoption.Inaddition,thesoftw
thatcomeswiththeprotocoladapterrequiresaWindowsOS,sosoftwarewouldneedtobedeveloped
specificallyfortheRS‐232interface.
adaptertoconvertRS‐485toR
single

are
Source:http://www.aprilaire.com/index.php?znfAction=ProductDetails&category=23&sub=
comm&item=8870

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