X10 and zero crossings

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gar

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151226-0026 EST

X10 data is not transmitted during voltage zero crossings. Rather transmission of a group of bits starts on a voltage zero crossing. During a command transmission each group of bits starts on a new voltage zero crossing.

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gar said:
151226-0026 EST

X10 data is not transmitted during voltage zero crossings. Rather transmission of a group of bits starts on a voltage zero crossing. During a command transmission each group of bits starts on a new voltage zero crossing.

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Click to expand...

Was there a question here?
 
151226-0824 EST

Sierrasparky:

Not a question, but it is an information statement.


iwire:

Yes it may help you do your job. Either in determining whether a certain product should be used, or in troubleshooting a problem. Previously in a prior discussion we had a small interaction on X10 reliability. Since then I have had an X10 relay plugged into a circuit with a TED-1000 system. With very low probability the TED-1000 signal has turned on the X10 relay. Is this a major problem? I don't know for the general public. For me it would be, and there seems to be a number of TED users that also have X10 units that have expressed concerns about these interactions at the TED Forum.

An understanding of how products work that you install or service can help you troubleshoot problems.

A while back one forum member had installed IR light controls for a driveway. The operation of the IR control was the problem. I can not find this thread at the present, but the problem boiled down to having an understanding of how the particular IR units worked. The original installed IR units had a solid-state relay/dimmer (at times) that caused the problem. Using IR units with an electro-mechanical relay output solved the problem.

In my search this thread came up --- http://forums.mikeholt.com/showthread.php?t=161381&page=4 . Again a knowledge of how the system works would help troubleshooting.

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151226-0915 EST

A little more on the X10 system. It can probably be described as an asynchronous data system using a clocked demodulation of data bits just following the 60 Hz power line +/- zero crossings.

There are actually three time slots each single phase half cycle spaced at 0, 120, and 240 degrees. This is to allow operation on three phase systems.

An X10 receiver will constantly look for a carrier pulse just following a zero crossing. The first carrier pulse is the async start bit. Following the start bit the next 9 periods just following a zero crossing are tested for a 0 (no pulse) or 1 (a pulse).

Interference from a TED signal is more likely to cause the failure of an X10 receiver to receive a command, than it is to turn on or off an X10 receiver.

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