Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[dbm]

Here is an interesting puzzle:

I have a system that includes a Leviton Wall Mounted Controller (#16450 + #16400 - basically three on/off addresses and a dimmer) and a Leviton Dimming Fixture Module (#6376).  The controller is on one circuit, the dimmer on another.

I recently installed a Japanese toilet seat (one of those with heater and jets) on the same circuit as the controller above.  All of a sudden, the light doesn't work anymore (the controller's LEDs go on and off, but the light fixture controlled by the dimmer doesn't go on and off).  If I move the controller to another circuit than the toilet seat, everything is fine.  Any idea what's going on?

Here is a hint and a guess.  When I unplug the toilet seat, the LEDs on the seat's controller stay on for a few good seconds.  Could the seat have a large capacitor which acts as a high-frequency filter, thus filtering the X10 commands also?  Is there another explanation?  Has anybody experienced something similar with other products/appliances?

Thanks!
Doug

[Puck]

If I move the controller to another circuit than the toilet seat, everything is fine.  Any idea what's going on?

The seat is either a noise souce or a signal sucker to the X10 signal.

...Could the seat have a large capacitor which acts as a high-frequency filter, thus filtering the X10 commands also?

Your seat very well could have a frontend capacitor that will look like a short to ground for the X10 signal (I.E. Signal Sucker).

The larger the capacitor, the less impedance it has as frequency goes up. So there is possibly a smaller capacitor as well on the frontend of the seat's power supply... this allows it to pass a Conducted Emissions test required for sale in certain markets; and it's usually this capacitor that degrades X10 signals.

[Dan Lawrence]

Is the seat a real Japanese product or a UL apporoved unit?  If it's Japanese, it may no be approved for US use.

[Brian H]

Sounds like you may need an X10 Powerline filter on the AC Power cord or a wired in filter if it is hare wired into an electrical box.

[dbm]

Is the seat a real Japanese product or a UL apporoved unit?  If it's Japanese, it may no be approved for US use.

It's a real Japanese product, so not UL approved and probably not approved for use in the US. 

I'll try the AC powerline filter, as suggested, although if the capacitor is the issue (thanks for agreeing, Puck), I doubt that will fix the problem.

[Charles Sullivan]

I'll try the AC powerline filter, as suggested, although if the capacitor is the issue (thanks for agreeing, Puck), I doubt that will fix the problem.

A power line filter designed for X10 will do the job.  Connect it between the offending appliance (the toilet) and  wall receptacle.  It will present a high impedance to the X10 signals on the power line as well as blocking any noise from the appliance.

[Brian H]

If the filter is between the AC feed and the seats power supply. It will prevent the seats cap from absorbing any X10 signals. That is if it is a X10 one that is tuned to the 120 KHz. Powerline signals frequency.

[dbm]

A power line filter designed for X10 will do the job.  Connect it between the offending appliance (the toilet) and  wall receptacle.  It will present a high impedance to the X10 signals on the power line as well as blocking any noise from the appliance.

Indeed, that did it.  Thank you very much for the suggestions.  Now I can have a warm butt and control the light.

[dbm]

To continue my saga, here is another question.

If I plug in the toilet seat directly (no filter), the wired-in controller does not work (we established that).  However, if I plug in an X10 RF received (one of those plug-in remote control receivers) and I don't filter the toilet seat, I CAN control the light.  Therefore, the signal from the remote control receiver is somehow "stronger" than the wired-in module.  Is there a wired-in module that is capable of generating a stronger signal just like the RF receiver?  The reason I'm asking is that I get the same problem not only with the toilet seat but also with the laptop power supply so I would hate to install filters on every single electronic device I plug in that circuit.

To summarize:

Circuit 1:
Wired-in Leviton light controller receiver module with dimmer

Circuit 2:
Toilet seat and/or laptop power supply
Wired-in Leviton controller transmitter (three on/off, one dimmer)
Plug-in X10 RF remote control receiver (two on/off with dimmer)

Light can be controlled with the X10 remote control receiver under all circumstances
Light can be controlled with the Leviton wired-in controller only if the toilet seat and laptop power supply are filtered

Thanks for all your help!

[Brian H]

The outlet you are using for the transceiver maybe on the same phase as the toilet seat controls. The Leviton maybe on the other phase or a more noisy branch circuit.
I have seen powerline output tests, but none have included the Levitons. So I don't have a reference point.
Computer and laptop power supplies are known for noise and or signal sucking.

[gil shultz]

Good Evening,

The problem you mention is common and a very complex one.  Assuming all the equipment is operating properly we know by definition that the signal is modulated on the power line at 120 kHz at the zero crossing point.  This allows a usable signal of a few volts to be impressed on a line that has over 150V peak voltage.  These signals are filtered with tuned circuits hence there is the possibility of alignment problems but they get a much stronger signal in the pass band.  Good filters etc will give good results; poor filters will give marginal results.  Remember that these units are low priced and at best have marginal filtering abilities.

The unit putting the voltage on the power line (transmitter) can only put out a few volts.  The receiving unit (module) has a minimum sensitivity level for a valid signal.  If the signal level is below the minimum erratic or no function occurs.  Conversely if the signal is above the minimum the unit should operate properly.

Noise will swamp the front end of the receiving unit decreasing or eliminating its ability to receive and disseminate a valid signal. Noise is typically generated by an outside source.

The carrying media (power wiring) was never intended to handle low frequency RF (Radio Frequency) signals not was it designed to block them. The solution is to get enough good signal to the module so it can perform properly.  Solving this gets complicated.

Attenuation of the signal is the proper way of saying the signal level is reduced.  There will always be some attenuation of the signal in any normal system.  The trick is to minimize the attenuation or at least keep it low enough so a good signal can get through. 

There are three primary things capacitance, inductance and resistance that will attenuate the signal to a non usable level.  Expect a combination of two or three of these working in conjunction to be causing the problem.

House wiring is a source of capacitance; the effect is definitely there at 120 KHz hence line length will have an effect.  The resistance in typical power wiring will have no effect.  The inductance can depend how the wire is routed and against what. 

Power transformers are designed to operate at 50 or 60 Hz; consequently they have a high inductance which will stop the 120 KHz signal.  You see this in a typical home and add a bridge between the phases to cause the 120 KHz to go around the transformer. The advantage of this is that your signals do not pass through to other systems.

AC (Alternating Current) loads such as heaters, lights etc consume AC and do not normally interfere with 120 KHz signals.  Motors may or may not depending on there design.   On the other hand electronic equipment most by design attenuates the 120 KHz signals.  This is because the FCC (Federal Communications Commission) has placed restrictions on both conducted and radiated emissions allowed on commercial and residential equipment.  Radiated emissions go through the air while conducted emissions go through the wiring.  We are concerned with conducted emissions when working with X10.

Look at the cord that connects the video from your monitor to your computer.  There is a swelling of some type near one or both of the plugs.  This normally contains ferrite which attenuates high frequency signals.

Electronics needs DC (Direct Current) to operate internally.  This comes from a power supply of some type.  In bygone years most power supplies were built with a 60 HZ input transformer which isolated the unit from the power line (120 KHz as well). Depending on the transformer design many of these were not a problem.

Then came transformer less electronics such as TVs, these use higher frequencies which have to be isolated from the power line.  The easiest way was to attenuate them.  The attenuators were cheep but efficient and would kill a broad range of frequencies including 120 KHz signals.  These do not pay any attention to the source of the signal they just attenuated them; this is consistent across just about all power supplies.

The cost of energy has kept increasing to the point energy conservation is important.  The best way to save energy is to use less.  The original power supplies at best could get an efficiency of 50%.  The transformer less designs was approaching the 70% efficiency range. This is not good enough today so the switch mode power supplies have become popular.  These are typically better then 95% efficient.  These use high frequency designs and power MOSFETs (Metal Oxide Semiconductor Field Effects Transistor).  The MOSFETs can switch in the Megahertz range, and generate lots of high frequency noise.  Consequently the line attenuators are much better and also attenuate the 120 KHz even more.
 
This is a short and simple explanation of what may be causing the problem; it is not an explanation of how to solve it, that is your job. The problems can and sometimes do get much more complicated then what I have covered her.

Good Luck
Gil Shultz