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[dhouston]

If these smart meters can shed loads, it would be interesting to learn what technology is used to switch the 100-200 amp load.  Many solid state power devices will generate waveform distortion at zero crossing, right where X10 communicates.  Do the smart meters use solid state devices to load shed?  Do they use IGBTs?  If IGBTs are used and the load shed is reconnected at any time during the cycle other than near zero crossing, the result can be very high di/dt which can be destructive to some types of loads.  I guess I need to setup that chart recorder to get some answers.

If my guesswork is on the right track, I'm not sure it matters what is used to shed the loads because the problems seem to arise where there is no load shedding hardware. One thread on the Smarthome forum alluded to the meters outputting pulses that could be used by third party devices to track power usage, etc. (perhaps to determine when to shed some load?) I think the person mentioning it is with ISY and they are doing some things in this area. The pulses may be enough to explain the random on/off X-10 events and they're the only thing that seems to cover all the reported variations. There's an X-10 FAQ that acknowledges the "spike/brownout" vulnerability.

• http://www.x10.com/support/x10trou.htm#on

I've tried to get the Zigbee Smart Energy specification to see whether the pulses are documented but, so far,  no download link has arrived in my email.

• http://www.zigbee.org/

[JeffVolp]

Here are a couple of snippets from another fellow who experienced a problem after installation of a smart meter:

However (aha!), the power company did put in a "smart meter" about a month ago.  Supposedly this system runs using low power RF on two different bands above 900 MHz.  I have found one sentence in a Duke Energy web note that says something more interesting:

"In most cases, the digital electric meter Duke Energy is installing uses Power Line Carrier technology to send data from the meter to a communications node mounted a short distance away on an outside transformer. This set up uses a very low power radio frequency (RF) signal that actually travels along the power line as opposed to through the air."

Duke Energy has no human beings working for it that I have found.  The meter may be read as often as every 15 minutes or as seldom as once a day, according to another Duke web note.

And more recently:

This morning I was walking in the next township over from ours and happened past a Duke meter reader.  I told him I thought he had been replaced with the smart meters.  He said that things were not working well and Duke was already planning to replace the presently installed units with a different unit in November.

Jeff

[Noam]

I may be way off here, but isn't there some FCC regulation that says that electrical devices can't cause unwanted interference with other electrical devices (I don't know the exact terms of the regulation, but you see it all the time with things like cordless phones, etc)?

Wouldn't that apply to the installation of a SmartMeter, too? If it interferes with the proper operation of a customer's existing X10 system, shouldn't the power company be legally obligated to remove it?

[dhouston]

Methinks we have a smoking gun. From http://en.wikipedia.org/wiki/Electricity_meter

Some meters have an open collector output that gives 32-100 ms pulses for a constant amount of used electrical energy. Usually 1000-10000 pulses per kWh. Output is limited to max 27 V DC and 27 mA DC. The output usually follows the DIN 43864 standard.

Searching on DIN 43864 results in numerous links from meter manufacturers that mention the pulses but none that I read really added any detail to the above quote.

Such pulses might indeed cause the apparently random events being reported. Somehow the pulses get past the transformerless power supply and directly affect the PIC in switches and lamp modules. X-10 designers also have had a tendency to let unused PIC pins float which can lead to problems. Insteon designs use different MCUs and better engineering so are probably immune which explains why there are no similar reports on the Insteon forums. They might, however, wreak havoc on UPB systems - UPB uses similar amplitude pulses for powerline communication.

As for noam's question, the FCC prohibition applies to unlicensed radio devices transmitting over the air. I don't think the FCC even regulates powerline communications (or conducted emissions) unless they radiate energy that interferes. Anyway, the interference referred to is with licensed use of the frequency in question and X-10 is neither licensed for PLC nor RF.

I have a Parallax USB 'scope which, IIRC, can be setup to trigger on a rising/falling edge. If I can dig it up along with a 25VAC transformer, I should be able to get some pictures. BTW, I just realized I had misread the duration of these pulses. 32-100ms can span 3-12 half-cycles - I had expected they were much shorter. Although, I have seen ms frequently misused when the writer meant µS.

[Dan Lawrence]

As I posted before in this thread, my electric meter in inside my house.  If BGE (Baltimore Gas & Electric) is pushing Smart Meters and can't prove it won't disrupt my X10 system, they don't get access, period.   I pay them for my electric service, they don't pay me.

[dhouston]

But the pulses could come from your neighbor's meter, as well. 

[dave w]

I may be way off here, but isn't there some FCC regulation that says that electrical devices can't cause unwanted interference with other electrical devices (I don't know the exact terms of the regulation, but you see it all the time with things like cordless phones, etc)?

Yes, but from an RF or emitted standpoint. I don't think the FCC gives a rip about spurious signals that remain contained in a conductor. If it is energetic enough, frequency wise, power wise, etc.  to start transmitting through open air, then they wake up, otherwise no.
 i.e even through 120kHz is considered in the radio spectrum, X10, Smarthome, etc is not required to get "Type Acceptance" for their plug-in controllers since the 120kHz is carried by wires and not by air.

[Backward Engineering]

A quick update on my random event problem.  I finished assembling the XTBM today and started investigating the problem.  I found a very high noise level on one side of my 120-0-120 volt service.  I traced the noise to a switch mode power supply located in my motorhome.  The power supply is a Todd PC75, 12 VDC 75 Amp unit switching at around 25Khz.  Depending on the duty cycle of the switching transistor,  the supply might be generating a large 120Khz component. The power supply had been is service for years with no X10 interference.  Something has changed in the operation of the power supply.  I'm now troubleshooting the power supply to find out why it is now a noise generator.  Probably failing filter capacitors.  I have had all of my X10 modules re-enabled (slide switch closed) now for several hours with no random events so far.  I now need to reinstall my X10 repeated and then, since I have the XTBM, I should check the signal strength throughout the house.  I would not have guessed that a random noise generator could have produced random X10 events, but it looks like that's what was happening.

Thank you Jeff for this valuable tool.

Don

[Knightrider]

Actually Don, we should be thanking you for taking the time to figure this out.  I'm tired of people just giving up on their X10 investments.  With a little trouble shooting and some "backwards engineering" most X10 problems can be solved.

Yes, Jeff is relentless in his pursuit to find new ways to make x10 compatible with all the newer technologies, but when people fail to read his tutorials, or fail to pick up one of his tools, it's still a lost cause.  Jeff has a new "tuned signal sucker" which might just do the trick on the motor home, but how many people know that?  I'm betting you'll just fix the caps in the camper, but there's more than one way to skin a cat.

Anyhow, have a +1 from me for bothering to report your findings and an eventual happy ending to this saga.

[JeffVolp]

Jeff has a new "tuned signal sucker" which might just do the trick on the motor home, but how many people know that?

Actually I also have an Active Noise Reducer (XTB-ANR) to combat noise.  The beta tests have gone well, and that unit is just going into early production.  That might do the job if it is plugged into a receptacle in the motorhome.

Jeff

[Noam]

Don -
Another +1 from me, too.

So, it looks like the SmartMeter is NOT the culprit here. That's actually good to know. However, something with the new SmartMeter might have caused a change in the noise being put out by the power supply in the motorhome, I suppose.

Is there a way to put an X10 noise filter between the RV and the house?

[JeffreyB]

The smart meter might not be his problem, but it sure as heck is mine...  Recap: 17 years of no problems.  The day my smart meter was installed, random events on various house codes (mainly very early in the morning 3-4am).  I even have a PZZ01 and an XPCR.  Both have not solved the problem.

Jeff

[Backward Engineering]

As of this morning, 18 hours with no random events.

 Thanks for the compliments.  A passive T network filter on the motorhome's 30A shore power plug might solve the problem but the power supply had not caused a problem until recently.  The timing of the power supply noise problem coincided with the installation of the smart meter.  With my background in power electronics engineering, I have no excuse for not addressing the problem methodically.  That means I will repair the power supply and then possibly add a filter .  The last thing I need is a 900 watt power supply located under the bed catching fire.

 I found a retired engineer on the internet that had reverse engineered a schematic of the power supply.  He offered free advice and a copy of the schematic.  The power supply already includes a line filter ahead of the bridge rectifier.  If anyone is interested in my findings and repairs of the power supply, post a request, otherwise I will proceed without comments on the repair.  I think the power supply repair might be getting off topic for this forum.

Alternate methods to solve the noise problem are:

Method 1) Pull the plug on the motorhome, get behind the wheel and hit the road.  Perfect isolation.  After all, I'm supposed to be retired.
Method 2) Finish the installation of solar panels on the motorhome (project #959) to maintain the battery charge and pull the plug.

I hope I didn't get too far off topic.

Don

[Noam]

... A passive T network filter on the motorhome's 30A shore power plug might solve the problem...

I am guessing that the term "shore power" is a holdover from the boating world, but it really shouldn't apply to motorhomes. Unless you are plugging it into to a power source on a boat, ALL power would be "shore power" (including the onboard generator or solar panels).

[Noam]

The smart meter might not be his problem, but it sure as heck is mine...  Recap: 17 years of no problems.  The day my smart meter was installed, random events on various house codes (mainly very early in the morning 3-4am).  I even have a PZZ01 and an XPCR.  Both have not solved the problem.

Jeff

I'm guessing that you don't have a motorhome (like Don), but perhaps there is some device in your home that is reacting "funny" to the new meter, and is putting out random noise that happens to look like commands? I know it is a long shot, but you never know.
Do you have a PC interface (like the CM11 or CM15), through which you can look at the Activity logs? If the "random commands" are only coming in on one or two (or a small number of) house codes, then perhaps you can fix the problem by moving your modules off those codes.