oscilloscope monitoring

[kevinvinv]

Hi-  I've got strange problems with one of my switches (a relay switch used for a flourescent load) and have so far done all the "typical" things like adding a decent phase coupler and etc.

I really want to check out the signals on my O-Scope.

What is the best way to go about this?

Thanks!!

[roger1818]

Hi-  I've got strange problems with one of my switches (a relay switch used for a fluorescent load) and have so far done all the "typical" things like adding a decent phase coupler and etc.

My first guess would be that the fluorescent light is generating noise on the powerline and drowning out the signal, but you have probably already tried putting a noise filter between the switch and the load.

I really want to check out the signals on my O-Scope.

What is the best way to go about this?

Here is a link on how to build and use an X10 Oscilloscope Adapter.

Good luck!  Let us know how it works.

[kevinvinv]

Yeah- even with no load at all connected...   the switch doesn't operate reliably.

Thanks for the link... I'll likely build that thing.

[Brian H]

Just follow the cautions. 120 VAC can bite. I used an X10Pro phase coupler to look at X10 signals myself. Used one phase for the power input and the other connected to the scope. Note the X10Pro unit has two sets of tuned [the X10 120Khz signal] isolated inputs. Some couplers have just the .1uf AC rated cap between the phase inputs or may add the 18uh tuning choke in series with the cap for phase coupling.

[roger1818]

I had a look at it and I would be very careful using it as it doesn't have any isolation and could present a shock hazard should the hot and neutral wires be reversed.  If I were to design it, I would use a transformer to step down the voltage (instead of a voltage divider) and then use a second capacitor to couple the neutral to the "Ch1, ch2 outer ground."

[kevinvinv]

OK so I built the O-scope adapter and found that sure enough--- signal is very very poor at many places around the house.  In addition-  I purchased the ELK meter and confirmed.

The house is around 3k  sq ft.  I have maybe 14 x10 devices-  none of them 2-way.

I am using a leviton repeater/active phase coupler.

The coupler is installed in the electrical panel.  I probe the signal at the terminals of the coupler (right in the panel) and the ELK reports only 2 or 3 bars of signal.  If I shut off all the circuit breakers but one-  I get full strength from the repeater (full scale).

I tried to see if one particular circuit loaded down the signal more than another and it seems that they all are about equal loaders.

So what do you think?  Shouldn't this Leviton boost the signal more?? 

Is there a SUPER POWER repeater out there?  What do you do if you simply have too much signal obsorption going on?

Thanks so much for any advice!!

[Brian H]

Sure sounds like the repeater is not working correctly.
I get in many rooms of my home 8 or 9 bars [same ESM-1 as you have] with my Smarthome 3 pin dryer repeater/Coupler. I also have the .1uf AC Rated cap across the phases in the electrical box.

[roger1818]

The house is around 3k  sq ft.  I have maybe 14 x10 devices-  none of them 2-way.

I am using a leviton repeater/active phase coupler.

A 3k sq ft house is a good candidate for a coupler/repeater but since you already have one, that should be sufficient.

So what do you think?  Shouldn't this Leviton boost the signal more??

I would have thought it should be doing a better job.  It could be defective like Brian said.

Is there a SUPER POWER repeater out there? 

I believe that the ACT CRs drive at 10V instead of the usual 6V.  I don't know for sure what voltage the Leviton drives at but it might be worth looking into.

What do you do if you simply have too much signal absorption going on?

First I would make sure you using noise filters on the most common signal absorbing devices (UPSes, powerbars, etc). 

Also do you have any Arc Fault Circuit Interrupters (AFCIs) or Ground Fault Circuit Interrupters (GFCIs) in your breaker panel?  They have been known to attenuate the X10 signal and being at the breaker panel, they could be dragging down the whole house.

As a last resort you could try using some signal amplifiers (such as SmartHome's BoosterLinc) on circuits that are particularly problematic.  Just make sure they aren't too close (electrically) to any powerline transmitters since they can actually weaken strong signals.

[roger1818]

I also have the .1uf AC Rated cap across the phases in the electrical box.

You shouldn't use both a passive coupler (including a cap) and a coupler repeater at the same time.  The passive coupler can actually weaken the signal from the coupler/repeater.  Even if it isn't doing that, it isn't doing you any good.

[Brian H]

Maybe but mine is best with both.

[roger1818]

Maybe but mine is best with both.

That is really strange.  As Phil Kingery says in Which One Should I Use - Part III (120/240v Residential Coupling):

I almost never recommend that a passive coupler and a coupler/repeater be used together. In the overwhelming number of instances they will cancel out each other, or at best, reduce their effectiveness. The repeater tries to send signal that it has specifically created for the "A" leg but the passive coupler steals part of it and puts it on the "B" leg where it isnââ,¬â,,¢t needed. Then they get in a big fight and its not a pretty thing to watch. So if you are ever installing a coupler/repeater, remember to take the old passive coupler completely out of the circuit. Donââ,¬â,,¢t think that if one is good, both are better. It doesnââ,¬â,,¢t work like that.

[kevinvinv]

Thanks All,  I will be trying your suggestions.  I do have a UPS that I can unplug and check on its effect.  I also will look into the ACT item... in fact Leviton referred me there this morning when I talked to them about the problem.

If you guys think that this residential repeater should drive a 3k ft**2 house though... I am indeed beginning to wonder if the repeater has gone bad...  I wonder what the chances of that are though...  most likely, I send it in... they send it back saying it is "ok" don't you think?

Thanks again.

[Brian H]

Well Phil has great insight into this. I can again try the passive one out. I don't know if the repeater being a plug in one on a dryer not at the main breaker box effects this. Easy test for me as I can turn off the two breakers it is on. Preliminary short test showed same controll with it out so maybe I can leave it out. With out it in the circuits it did kill my other protocol communications.

Phil also brought out one more point. Not all breakers next to each other on opposite phases. So maybe double checking that the repeater is on both phases maybe a thing to look at.

[steven r]

BTW... Is there any simple way of telling if something is on one phase or the other?

[kevinvinv]

One thing you can do to tell if two outlets are NOT on the same phase is this:

Take a voltmeter,  get some long wires. 
Put it on AC voltage range
Stick the black lead into the hot terminal of outlet A  (This is the small blade terminal)
Stick the red lead into the hot terminal of outleb B (Again, the small slot).

If the two outlets are on the same phase- you wont read much Voltage
If the two outles are on opposite phases,  you'll see 220V on the meter.

Sound ok?