TECH NOTE X-10 Communications Protocol and ... - X10PRO.com

TECH
NOTE
X-10Communications Protocol
and
PowerLine Interface
PSC04 &PSC05
REV 2.4

PSC04/PSC05 PowerLine InterfacesIntroduction
The X-10PRO codeformat is the"DeFacto" standard for PowerLineCarrier(P.L.C.)transmission.The
code format was first introducedin 1978for theSearsHomeControl Systemand the RadioShack
Plug 'n PowerSystem.Sincethen,X-10PRO has developed and manufactured O.E.M.* versionsof its
HomeControl Systemformany companiesincludingIBM,Leviton Manufacturing Co.,General
Electric,RCA,Philips,Stanley and Leviton.Wealsodistributethesystem in Canada andhave
manufactured OEM versionsofthesystem forGermany,Holland,France,Switzerland,Japan and
Australia.
Allof thes esystems usetheX-10PRO codeformat,all arecompatibleand virtuallyallP.L.C.Home
Automation Systems currentlyavailablein theUSA useX-10 PRO Modules developed and
manufactured byX-10PRO.It is thereforeadvantageous for any HomeAutomation Systemtobe
compatiblewith theX-10 PRO standard.This enables any O.E.M.to takeadvantageof theverylarge
installed base of X-10PROcustomers as well ashaving access totheextensive arrayof different types
of X-10PROModules available.
TheX-10 PRO code formatis patented
However,in ordertoencourageothers totakeadvantageof thelargeinstalled baseof X-10PRO
Modules and develop theirown systemstocontrol theseModules,thePSC04and PSC05 PowerLine
Interfaces areoffered as cost effective ways of coupling X-10PRO compatible signals onto the AC
powerline.Permission totransmit theX-10PRO codeformat is granted topurchasers of thePSC04
and PSC05Power Line Interfaces.
The PSC04is atransmitterand thePSC05isatransmitter-receiver.Both plug intoregular AC outlets
and connect totheOEM product via amodular RJ11telephonejack.Both interfaces providean
opto-coupled 60Hzsquarewave,synchronized to the zerocrossingpoint of theACline. TheOEM
generates X-10 PRO compatiblecodes synchronized tothis zero crossing point.ThePSC04and
PSC05 then coupletheX-10PRO codes ontotheAC line.Thus all patent related criteria aresatisfied
within theinterfaces.
This alsorelievestheOEMof any U.L.or C.S.A. considerations as all powerlineconnections aretaken
care of by theinterfacesand all connectionsbetween theinterfaces and the OEM productare optocoupled.
Two-Way transmissionavailable
The PSC05is similaris concept and design to the PSC04but provides ameans to transmit and
receive X-10PRO codes.AnyOEM product designed to receiveX-10 PRO codes MU STusethePSC05.
X-10PRO willnot grant permission toreceiveX-10PRO codes byany othermethod.
The PSC05enables an OEM todevelop asystemtocontrolX-10PRO Modules,and receiveX-10PRO
signals from remote sensors(P.I.R.motion detectors for example).
The PSC05lets theOEM transmit a"polling" codetothePAT012-WayTransceiver ApplianceModule.
The PAT01responds by transmitting aspecific codetoindicate its status (on oroff).ThePSC05then
receivesthiscode.When used with the PAT01,thePSC05givestheO.E.M.theability to implement a
full2-Way systemwith collision detectio nand contention resolution. OtherX-10PRObi-directional
Productsinclude:PLM21Two-way Lamp Module,PAM21and PAM22Two-way 15A ApplianceModule
(2pin and 3pin)
X-10PROCodeTransmission (PSC04andPSC05)
To transmit X-10PRO signals the OEMmust supply 1ms "envelopes" totheTX input of theinterface
with respect tocommon.Theseenvelopesmust beas closeas possibletothezerocrossing point of
theAC line(seetiming diagrams).An opto-coupledoutput representingthezerocrossing point of the
powerlineis provided fortheOEM towhich X-10PRO codes aretobesynchronized.
*0.E.M. =0riginal Equipment Manufacturer. 1

X-10 PRO CodeReception(PSC05 only)
ThePSC05 uses acustomproprietary IC to read X-10PROcodesfromthepower line.Thistakes alot of
burden off the microprocessorin theOEM product as theO.E.M.microprocessor doesnothaveto
continuouslymonitor thepowerlineand check all incoming signals (and noise) forvalidity.Any signals
applied totheOEM product areerror-checked, valid X-10PRO codes.Whenavalid X-10PRO codeis
received, it isstored in the custom IC and applied(in envelopeform) to the O.E.M.product.This output is
coincident with thesecond X-10PRO transmission. (X-10PRO codes arealways transmitted in gro ups of
two,except forBright and Dimseenote3, page5).
Data sent to the OEM productis valid X-10PRO data.TheStartCode(1110) can beused to alert the
OEM product that an X-10 PRO codewill follow.A"1" bit from the PSC05appears asanegativegoing
pulse1.1mslong,beginningapproximately 100ms afterzerocrossing.TheOEM should samplethis
data between 500and700ms after zerocrossing.
TheLED on thePSC05gives avisual indication that X-10PRO codes arebeing received.TheLED is
illuminated when AC power is applied tothePSC05, and blinks off when X-10PROcodes arereceived.
ThePSC05 will alsoreceivethecodes ittransmits,thereforetheLED will alsogivean indication of codes
being transmitted.
Theability toread X-10PRO codes fromits own output alsoallows theOEMtoincorporatedata collision
detection.If thecodereceived differsfromthecodetransmitted,thecodecan beassumed tohave
been corrupted by noise(oranothertransmission)on thepowerline.
TheLineMonitor capability of thePSC05allowstheOEMtoensurethat thepower lineis free fromX-10
PRO signals beforestarting atransmission.This means thatin amulti-transmittersystemtheOEM can
minimizeco ntention between transmitters. For example,if afterdetecting thattheline is free,a
transmitterwaits forarandomnumberof powerlinehalf cycles beforetransmitting,the chanceof
collision isreduced.Adifferent prioritycan beassigned to each transmitterbyincludingafixed delay
beforetherandomdelay.Theshorter the fixed delay,the higherthepriority.
Important SafetyNotice
OV Inthis productIsdirectlyconnectedto one side of the ACline.
Therefore, forsafety,an ISOLATINGpowertransformerMUSTbe Usedwhen
attemptinganyInternal measurernents.
Thepowersupplies in the PSC04andPSC05arecapacitively derived from,and directly referencedto,
the120volt AC powerline. Care should be taken when monitoring anyinternalcircuitry with an
oscilloscope,as the0VreferenceinthePSC04 andPSC05 areNOT isolatedfrom 120 volts.
2

Transmission Theory
X-10PRO transmissions aresynchronized tothezerocrossing point of theAC powerline.Thedesign goal
should betotransmit as closetothezerocrossing pointas possiblebut certainly within 200
microseconds of thezero crossing point. ThePSC04and PSC05provide a60Hz.squarewavewith a
max.delay of 100microseconds from the zerocrossingpoint of theAC powerline. Themaximum
delay between signal envelopeinput and120KHz.output bursts is 50micro seconds.Therefore, it should
bearranged that outputs tothePSC04and PSC05bewithin 50 microseconds of this 60Hz. z ero
crossing referencesquare wave.
ABinary 1isrepresented by a1millisecond burst of 120KHz.at thezerocrossing point andaBinary0by
theabsenceof 120KHz.ThePSC04 and PSC05modulatetheir inputs(from the OEM) with 120KHz.,
therefore only the1ms "envelope" need be applied totheir inputs.These1millisecond bursts should
actually betransmitted threetimes to coincidewith thezerocrossing points of allthreephases in athree
phasedistribution system.Figure1shows thetiming relationship of thesebursts relativetozerocrossing.
Figure 1.
1ms
2.778ms
5.556ms
8.333ms
Figure 2.
2.778ms
5.556ms
8.333ms
120khz
60hz
120khz
60hz
Note.-Forclarity,thesignals in figure1areshown as
theywould beseen through ahigh pass filter.The
60Hz.waveformis only shown forreference.In realitythe
signals areactually superimposed on the60 Hz.
waveform and lookmorelikethat shown in figure2.
Acompletecodetransmission encompasses eleven
cycles of thepowerline.Thefirst twocyclesrepresent a
Start Code.Thenext fourcyclesrepresent the House
Code and thelast five cycles represent eitheraNumber
Code (1thru 16)oraFunction Code(On, Off etc.).This
completeblock,(Start Code,House Code,Key Code)
should always be transmittedin groupsof2with 3power
linecy cles between each groupof2codes.Bright and
dimare exceptionstothisruleand should betransmitted
continuously(atleasttwice) with NO gaps between
codes.Seefigure3.
PowerLine Cycles
Codetransmittedwhena Number buttonispressed
CodetransmittedwhenaFunction buttonispressed
Figure 3.
Within each blockof data,each fouror fivebit codeshould betransmittedin trueand complement
formon alternatehalf cycles of thepowerline.i.e.if a1millisecondburst of signalistransmittedon one
half cycle,(binary1)then nosignalshould betransmittedon thenext half cycle,(binary0).SeeFigure4
below.
3

TheTables in figure5.show the Binary Codestobetransmitted for each HouseCodeandKey Code.The
Start Codeisalways 1110 which is auniquecodeand is theonlycode which doesnot followthetrue
complement relationship on alternate half cycles.
Figure 5.
House Code andKeyCode Tables.
Hail Request istransmitted toseeif thereareany other
X-10 PRO transmitters within listening range.This allowsthe
OEM toassign adifferentHousecodeif a"Hail
Acknowledge" is received.
In aPre-Set Dim instruction,theD8bit represents theMost
Significant Bitofthelevel and H1,H2,H4and H8 bits
represent the4Least Significant bits
TheExtended Data codeisfollowed by8bit bytes which
can represent Analog Data (after Ato Dconversion).There
should benogaps between theExtended Data codeand
theactual data, and nogaps between data bytes.The
first8bitbytecan be used tosayhow manybytesofdata
will follow.If gaps areleft between data bytes,these
codes couldbereceivedby X-10PRO Modules causing
erroneous operation.
ExtendedCodeis similartoExtended Data:8Bit bytes
which followExtended Code(with nogaps) can
represent additional codes.This allows thedesignerto
expand beyond the256codescurrently available
IMPORTANTNOTES
NOTE 1.X-10PRO ReceiverModules require a"silence" of
at least3powerline cycles between each pair of 11bit
codetransmissions(nogaps between each pair).The one
exception tothis ruleis bright and dimcodes.These aretransmitted continuouslywith nogaps between
each 11bitdimcodeor 11bit bright code. A3cyclegapis necessarybetween different codes,i.e.,
between bright and dim,or 1and dim,or on andbright,etc.
NOTE 2.The PSC05Two-WayPowerLineInterfacecannot receiveExtended CodeorExtendedData
because thesecodeshavenogaps between them.ThePSC05can onlyreceive standa rd"pairs" of 11
bit X-10PRO codes with3powerline cyclegaps between each pair.
NOTE 3.The PSC05can receivedim and bright codes but theoutput willrepresent thefirst dimor bright
codereceived,followedby everythirdcodereceived.i.e.theoutput fromthePSC05willnot bea
continuous streamof dimorbrightcodeslikethecodeswhich weretransmitted.
Transmission Timing Diagrams.
Asquare waverepresenting zerocrossing detect is providedby thePSC04/PSC05and is within 100ms of
thezero crossing point of theAC powerline.Theoutput signal envelope fromtheOEM should bewithin
50ms of thiszerocrossingdetect.Th esignalenvelopeshould be1ms(-50ms +100ms).SeeFigure6.
4

Opto-Coupled 60 Hz. referenceoutput (fromthePSC04/PSC05)
Zeroxing
detect
Max. allowable
delayfromzero
xingdetect-
50microsec
120VAC 60 Hz.
Max.delay
+100
micro seconds
Figure6.TransmitTimingDiagrams.
From PSC04/PSC05
X-10 envelope
Input From O.E.M.product
1ms-50microsec
+100microsec
120Khz.output
Max.delayfrominput
envelope0-1transitionto
outputreaching90%level
-50microseconds(5Ohmload)
OnACpowerline
Transmissions aretobesynchronizedtothezerocrossing
pointoftheAC powerlineand should be as closetotrue
zerocrossing as possible.ThePSC04 and PSC05are
designed tobeinterfaced toother microprocessor
circuitry which outputs X-10 PRO codes synchronized to
thezerocrossing point of theAC power line.It is therefore
necessary toprovide azerocrossingreferencefor the
OEM microprocessor.
It islikely that this microprocessor will have its own
"isolated" powersupply.It isnecessarytomaintain this
isolation,thereforethe triggercircuitnormallyused in X-10
PROcontroll ers isnotdesirableas this wouldreference the
OEM power supply totheAC power line.It is alsonot
desirabletotakethetrigger fromthesecondarysideof
thepowersupplytransformer as somephaseshift is likely
tooccur.It isthereforenecessary toprovidean
optocoupled 60Hz.reference.
An opto-coupled60Hz.squarewaveisprovided atthe
output of thePSC04and PSC05.X-10 PRO codes
generated bytheOEM product aretobesynchronized
tothis zerocrossing reference.The X-10PRO code
envelopegenerated by theOEM is appliedtothe
PSC04 orPSC05which modulatestheenvelopewith 120
KHz.an dcapacitivelycouples it totheAC power line.
Opto-Coupled Signal Input (tothePSC04/PSC05)
Theinput signal requiredfromtheOEM product is thesignal"envelope" of theX-10PRO codeformat,i.e.
High for 1ms.coincident with zero crossing representsabinary "1" and gatesthe120KHz.oscillator
through totheoutputdrivecircuitthus transmitting 120 KHz.onto the AC powerlinefor 1ms.
Low for 1ms.coincident with thezerocrossing point represents abinary "0" andturns the120KHz.
oscillator/output circuit off fortheduration of the1msinput.
Opto-Coupled Signal Output(fromthe PSC05)
The"X-10PROreceived" output fromthePSC05coincides with the second half of each X-10PRO
tran smission.This output istheenvelopeof theburstsof 120KHz.received. Onlytheenvelope
corresponding to the first burstofeach group of 3bursts is availableattheoutput of thePSC05.See
figures7, 8and 9.
Figure 7. "X-10received"outputfromPSC05 5

Receive TimingDiagrams
Figure8.
Figure9.
PSC05
PSC05
6

PSC04 Block Diagram
Connection between theOEM product is
viaastandard modularphonejack,the
connections forwhich areas follows:
1. BZerocrossingdetect output (with respect
to2).
2.RZerocrossing detect common.
3. GX-10transmit envelopecommon.
4. YX-10transmit envelopeinput (with
respect to 3).
PSC04
OEM
Product
PSC05
1
2
3
4
Opto #1
Opto #2
Opto #3
Optos'
Trigger
Com.
Com.
Signal
-15v
-30v
0v
120kHz.osc.
O/P drive cct
Zeroxing Det.
PowerSupply
Zero Crossing
Detect
-15v
Code DetectIC
Gate
120kHz
Oscillator
-15v
-15v
-30v
PSC05BlockDiagram
Connection between theOEM product is
via astandard modularphonejack,the
connections forwhich areas follows:
1. BZerocrossing detect output (with respect
to2).
2.RCommon.
3. GX-10 received envelopeoutput.
4.YX-10transmit envelopeinput (with
respect to2).
-15v
Amplifier
-30v
Power
Supply
Filter
120V60Hz.in
120Khz.out
1234
Coupling
Transformer
-30v
120VAC
60Hz
Fuse
7

PSC04Electrical Characteristicsat25DegC
ACinput voltage. 100-130VAC60Hz
Max.voltagebetween any +/-50V
terminals(1,2,3 and4)
Storage temperature -40to+70DegC
Operatingtemperature -10to+50DegC
DC characteristics
Serialdatainput
Min. Logic '1' 4Vinput will sink approx. 2.5 mA
Max.Logic'1' 20Vinput willsinkapprox. 18 mA
Max.Logic'0' 0.8Vinput willsinkapprox.0.1 mA
(Voltagesandcurrentswith respectto terminal 3).
Note:Thisoutput isanopen collectortransistor. Therefore,
the logic '1' voltage isquotedasareferencefordefining
the outputleakage current. An output pullupresistoris
requiredtogenerate alogic level. Thep ullupcan be
returnedto anyvoltage upto the+20V withrespect
toterminal2.
ACcharacteristics
RFoutput to 60 mW averageinto a5Ohmload
ACpowerline. (5Vpk-pkinstantaneous).
Carrierfrequency 120Khz. +/-2Khz.
Max.phase delay 100usec.
between zerocrossing
point of AC powerline
andzero crossingdetect
output(eithertransition).
Max.allowable delay 50 usec.
between transitionson
zero crossingdetect
outputandserial data
input '0'-'1' transition.
Max.delay between 50 usec.
serial inputenvelope
'0'-'1' transitionand
carrierburstreaching
90%level.
WidthofX-10 PRO 1ms+100 us -50us
envelop e
Isolation voltage 2500 Vr.m.s. 60
Hzfor 1min.
PSC05ElectricalCharacteristicsat 25DegC
AC inputvoltage. 100-130VAC 60Hz
Max. voltage betweenany
terminals(1,2,3and4) +/-50V
Storage temperature -40 to+70DegC
Operatingtemperature -10 to+50DegC
DCcharacteristics
Serial datainput
Min. Logic'1' 4Vinput willsinkapprox.2.5 mA
Max. Logic '1' 20 Vinputwill sink approx. 18 mA
Max. Logic '0' 0.8Vinputwill sink approx. 0.1mA
(Voltagesandcurrentswithrespecttoterminal2).
Note: Thisoutputisan opencollectortransistor.Therefore,
the logic'1' voltage isquotedasareference fordefining
the output leakagecurrent.Anoutput pullupresistoris
requiredtogeneratealogiclevel.Thep ullupcanbe
returnedtoany voltageuptothe+20Vwith respect
to terminal 2.
AC characteristics
RFoutputto 60 mWaverage intoa5Ohmload
AC powerline. (5Vpk-pk instantaneous).
Carrierfrequency 120Khz. +/- 2Khz.
Max. phasedelay 100 usec.
betweenzerocrossing
pointof AC power line
andzerocrossingdetect
output (eithertransition).
Max. allowabledelay 50 usec.
betweentransitionson
zerocrossingdetect
output andserialdata
input'0' -'1' transition.
Max. delaybetween 50 usec.
serialinput envelope
'0' -'1' transition and
carrierburst reaching
90%level.
Width of X-10PRO 1ms+100 us-50 us
envelop e
Isolationvoltage 2500Vr.m.s. 60
Hz for 1min.
8

PSC04 Complete Schematic Diagram
PSC05 Complete Schematic Diagram
9

TypicalOEMConnectionDiagram
PSC05
PSC04/PSC05
PSC05
PSC04
10