7/27/2019 x10 Protocol

1/2

50hz

120khz

1 ms

3.333ms

6.667ms

10 ms

Figure 1.

Figure 2.

120khz

50hz

3.333ms

6.667ms

10 ms

PowerLine Cycles

Code transmittedwhena Numberbuttonispressed

Code transmittedwhena Functionbuttonispressed

Figure 3.

Transmission Theory

X-10 t ransmissions are synchronized to the zero crossing pointof the AC powerline. The design goalshould be to transmit asclose to the zero crossing pointaspossible butcertainlywithin 200microseconds of the zero crossing point. The PSC04and PSC05provide a 5 0 Hz. square wave with amax. delay of 100 micro seconds from the zero crossing point of the AC powerline. The maximumdelaybetween signal envelope input and 120KHz. outputbursts is50 micro seconds.

A Binary1 isrepresented bya 1 millisecond burst of 120KHz. at the zero crossing point and a Binary0the absence of 120KHz. The XM10 modulate its input(from the OEM) with 120KHz.,therefore only the 1 ms"envelope"need be applied to their inputs. These 1 millisecond bursts shouldactually be transmitted three times to coincide with the zero crossing pointsof all three phases in a thrphase distribution system. Figure 1 showsthe timing relationship of these bursts relative to zero crossing

Note. - Forclarity, the signals in figure 1 are shown astheywould be seen through a high pass filter. The5 0 Hz. waveform isonly shown forreference. In realityt

signalsare actually superimposed on the 50 Hz.waveform and lookmore like that shown in figure 2.

A complete code transmission encompasses elevencycles of the power line. The first two cycles representaStart Code. The next fourcycles represent the HouseCode and the last five cycles representeithera NumbeCode (1 thru 16)or a Function Code (On, Off etc.). Thiscomplete block, (Start Code, House Code, KeyCode)should alwaysbe transmitted ingroupsof 2 with 3 powline cyclesbetween each group of 2 codes. Bright and

dim are exceptionsto thisrule and should be transmittecontinuously(at leasttwice) with NO gapsbetweencodes. See figure 3.

Within each blockof data, each fouror five bitcode should be transmitted in true and complement

form on alternate half cyclesof the powerline. i.e. if a 1 millisecond burst of signal istransmitted on onhalf cycle, (binary1)thenno signal should be transmitted on the next half cycle, (binary0). See Figurebelow.

3

7/27/2019 x10 Protocol

2/2

The Tables in figure 5. show the Binary Codesto be transmitted foreach House Code and KeyCode. TStart Code isalways1110 which isa unique code and is the onlycode which doesnotfollow the truecomplementrelationship on alternate half cycles.

Hail Request istransmitted to see if there are anyotherX-10 PRO transmitterswithin listening range. ThisallowsthOEM to assign a differentHousecode if a "HailAcknowledge"is received.

In a Pre-Set Dim instruction, the D8 bit represents the MSignificantBitof the level and H1, H2, H4 and H8 bitsrepresent the 4 Least Significantbits

The Extended Data code isfollowed by8 bit byteswhican representAnalog Data (afterA to D conversion). Thshould be no gaps between the Extended Data code athe actual data, and no gaps between data bytes. Thefirst 8 bitbyte can be used to say howmanybytesof dawill follow. If gapsare left between data bytes, these

codescould be received by X-10 PRO Modulescausingerroneousoperation.

Extended Code is similar to Extended Data: 8 Bit byteswhich followExtended Code (with no gaps) canrepresentadditional codes. Thisallows the designertoexpand beyond the 256 codescurrently available

Figure 5.House Code and KeyCode Tables.

4