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There are so Many !
What's the difference ?

The difference is only skin-deep

One of the first things you discover about the X-10 system is that there are so many different 'brands' and types of lighting controls.

Even if you just look at the most common plug-in lamp module, you will find almost a dozen different brands !

lamp module
This is one example of the common X-10 lamp module.

Other 'brand names' you might see:

X-10 PowerHouse,
Radio Shack Plug N Play,
IBM Home Director,
RCA, Leviton, Stanley,
Safety 1st,
BSR (very old)

"X-10 Inside"

Some of the brands may have slightly different packaging, but basically they will all have the House and Unit code dials, and a two-prong socket on the bottom.

All of these models, regardless of what they look like on the outside, are manufactured by X-10 in one of their two large factories in China. These other companies simply pay X-10 to produce them with different labels and packaging.

Is there any 'real' difference? Although the circuit is always the same, it can be that there are differences in the 'quality' of the components as well as the amount of final testing.

In typical OEM (original equipment manufacturing) agreements, it is common to specify particular levels of intermediate and final testing of the product and its components. Of course the greater degree of testing means greater cost per unit, and a corresponding expectation of lower failure rates. However, in any mass production of such small but complex devices, it is impossible to achieve 'zero defects'.

X-10 has been manufacturing these most common devices for over 20 years, and it is very admirable that considering the numbers, the failure rate is quite low.

Basic Functions

The X-10 plug-in lamp module responds to several different X-10 powerline commands, not all of which are intuitively obvious. Only rarely will you find one that will not correspond to the following behavior:

X-10 ON
Lamp turns on to full brightness.

X-10 OFF (*)
Lamp turns off absolutely.

X-10 BRI (brighten) (*)
Lamp brightens by about 5%.

X-10 DIM (*)
Lamp dims by about 5%.

X-10 ALL Lights ON for Housecode
All lamp modules with the specified House code turn full ON

X-10 ALL Lights OFF for Housecode
Common X-10 lamp modules will not respond to this command.

X-10 ALL Units OFF for Housecode (*)
Common X-10 lamp modules will turn full OFF.

Local Switch Sense

All of these plug-in modules have a nice feature called 'Local On'.

If the lamp is OFF, and you simply twist or toggle the switch on the lamp, the module will sense this and expect that you are wanting to turn on the lamp 'locally', and will immediately turn the lamp ON.

The only thing is that the lamp will turn FULL ON, and there is no signal to the home controller that the change has been made. XTension will still think that the lamp is OFF. (See the next tutorial about smarter dimmers.)

(*) The NOVA Effect

One thing that will irritate you is that IF you turn OFF one of these lamp modules, and then issue a DIM or BRI command, it will first turn full ON, and then attempt to dim. This is commonly nick-named the "Nova Effect", because it almost always happens late night when you least expect it.

There is a good electrical explanation why the modules were designed to do this, but it's best thought of when you consider the fact that most household fans have switches that turn on high before switching to a lower speed.

(*) Avoiding the NOVA Effect

It doesn't matter whether you use XTension or those bed-side manual X-10 controllers. If you ever turn a lamp module OFF, the next time you send it a command of any type, it's going to go full ON first.

The best thing to do is never turn it OFF.

It is impossible to completely avoid this if you have hard switches or the manual X-10 controllers. Someone is going to hit the OFF switch sometime, and of course there is always the chance for a complete power failure which will force the unit OFF.

But, for the most part you can avoid the nova effect by remembering to always simply press the DIM button on the manual controller until the lamp appears to be OFF.

Of course, it's not really OFF. There is still a tiny bit of current going to the lamp, and sometimes those with sensitive hearing can still hear a 'buzz' or whine. Not all units will do this, and it is reported that some light bulbs will cause the unit to buzz more than others. (Phillips brand light bulbs are reported to be those that are the least offensive)

(*)Using XTension to help avoid the NOVA Effect

One of the earliest additions to XTension was the 'simulate preset dim' feature.
This option is set in the 'Edit Unit' dialog, whenever you add or change a 'dimmable' unit.
Whenever you issue a command thru XTension to turn OFF a unit which has been so optioned, XTension will simply issue sufficient number of DIMs so that that unit is DIM'd to zero.

Since this avoids the hard OFF command, the next time you command the lamp to brighten, (even from a manual controller), the lamp module will nicely brighten the lamp up to the desired level without going full ON first !

Another method is to always write your scripts so that they never actually send an OFF command to one of these common lamp modules...such as :

dim "Bed Lamp" to 0

Another little 'gotcha' called the "Black Hole Effect"

On the older X-10 dimmer modules and wall switches, there is an annoying habit of these units, that IF they are not OFF, they will not respond to an ON command.

For example, if the lamp is at 50%, and you send it an X-10 ON command, the lamp will not brighten to 100% like you would think. It does nothing.

But the unit will still respond to Brighten or Dim commands, as is reasonable.

The best way to avoid this condition is to let XTension handle it as a 'simulated preset dim' unit. It will never be sent an OFF, or an ON, and both the NOVA and the Black Hole effects can be avoided. (most of the time)

About the 'simulate preset dim' option

For several years, this 'nova effect' problem has been attacked by different manufacturers, and now there are newer lamp modules that are available which are capable of remembering their last brightness state, and when they are turned OFF, they will nicely brighten up to that last known level.

These newer modules cost between 3 and 10 times as much as the lowly old X-10 lamp module, and are not as readily available. (ie: from your local Radio Shack)

The annoyance of the nova effect is enough to encourage many to buy these modules in spite of the extra cost. For this reason, we thought that it would be a great feature to incorporate into XTension. You simply set the option, and XTension remembers the 'preset' level instead of making each of the modules remember.

You simply write scripts and create scheduled events which just 'turn on' the lamp, and XTension remembers to 'brighten' the unit to the desired level. When you want to turn OFF the lamp, you simply say 'turn off "Bed Lamp", and XTension remembers to just DIM it to zero.

Setting the 'simulated preset' level in XTension.

The nice thing is that you can change the 'preset' level with XTension according to the time of day etc.

In the middle of the night when you stumble into the bath room you don't want the light to come on as brightly as you might at other times.

So you create a Scheduled event that "Presets" the Bathroom Light to your preferred level.

Of course you'll want to have another scheduled event in the morning that 'presets' the Bathroom Light to your preference for the Daytime...

The key is that anytime you explicitly tell XTension to dim or brighten a unit that is specified as a 'simulate preset dim', XTension will remember that value as the new preferred brightness level.

Do see the XTension Manual about the use of the verb "sim preset".

This verb lets you set the preferred preset level without actually commanding the Unit.

sim preset "Bathroom Lights" to 40

Funnies and not-so-funnies

If you dim or brighten the "Bath Light" from a manual controller, the lamp will indeed see the commands on the powerline, and dim or brighten accordingly.

XTension will also see these DIM/BRI commands to that unit and will accordingly set the 'current level' of the unit in the database to that new brightness level.

XTension will also make that new level the 'preset' level. So that the next time you issue a command to 'turn on "Bath Light", XTension will brighten that lamp to the 'remembered' level.

This means that unless you incorporate specific steps into your 'bedtime' or 'good morning' type scripts, that level that was set manually will be the level that is remembered, and the level to which the lamp will be set by XTension. This may not be your intention.

Either you must have specific scripts that set the 'preset' level to the desired level according to the time of day, OR remember never to manually DIM/BRI that unit.

Simple Wall-Mount Dimmers

Along with the plug-in type of X-10 dimmers, come several different models that you can install into the common wall boxes in your home.
wall dimmer
wall dimmer

These units behave very much like the plug-in models, with the exception that they do not have the 'local on' feature.

It has long been a disappointment that the WS467a has a funny button, and isn't as familiar as the old 'toggle' style manual switches. For this reason, several brands (still X-10 inside) of 'Decora' type paddle switches are offered.

These look better, but often have a 'mushy' or odd feel to them. There are different models, and those from Leviton do have a better feel. Still, there is much to be desired in these wall dimmers, so there are always new ones coming out.

I suggest that you not buy a whole house full of these until you make sure that you are happy with their operation and 'feel'.

You might want to check out the new 'SwitchLinc' model that not only has a much better 'feel', but offers some great features like internal 'preset dim'. The tutorial about smarter dimmers talks of this one.

CM11 versus LynX and other X-10 controllers

The X-10 controller (CM11/Activehome etc), is much better at 'tracking' the incoming DIM/BRI commands from a manual controller.

The LynX and other X-10 interfaces which rely on the "TW523" , are limited by the ability of the TW523. They cannot 'see' more than about 1 out of 3 of the incoming DIM/BRI commands.

This means that if you are using one of those interfaces, whenever you issue DIM/BRI commands from a manual controller, then XTension will get 'out of sync' with the actual brightness level of that unit.

Regardless, of which of the supported X-10 interfaces you use, it is always a good idea to have a 'garbage collector' kind of script which periodically goes around and sets your dimmable units to the desired 'preset' level according to the time of day.

Groups of Units

Don't forget that XTension lets you create 'groups' of units so that they can be controlled with a single command. XTension will honor the options of each unit of a commanded group so that you can mix-n-match units which are 'on/off', 'dimmable' and 'simulate preset dim' types.

A script that says: turn off "All Inside Units" will do just the right thing
for each of the units that are in the group:

- non-dimmable units will be 'turned off'
- dimmable units without 'simulate preset dim' will be turned off
- dimmable units with 'simulate preset dim' will be dimmed to zero

Other types of X-10 lighting controls

There are many new products available now. Most are much more expensive than the old X-10 lamp module, but offer spiffy new features that you may want.

( another article about these new lighting modules )
better lights
Better Dimmers

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Last modified: October 17, 2007
Michael Ferguson, webmaster@shed.com