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How to increase the current capacity of an XM17A or similar addressable PS?

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bkenobi:
Although it would be nice to have DC adapters that were directly X10 addressable, I don't personally think modifying one that is speced to low would be the best solution.  I'm not an EE, but it seems to me that it would be easier/safer to just use an appliance module with a relay (as Brian suggested) rather than taking a chance at violating the ratings and having insurance deny your claim for the house you burned down.   :o

HA Man:

--- Quote from: Brian H on June 14, 2016, 10:12:23 AM ---I am not an AHP expert but it maybe able to emulate the mutually-exclusive action. Using Appliance Modules.


--- End quote ---
I know of one way to do it in AHP, but it takes a bit of "programming" to do it, and ties-up the monitored house code "bank"... Of course, if one used multiple interfaces, with one dedicated to the camera control function, then tying-up a monitored house code in the dedicated interface wouldn't necessarily be a problem, overall.

I think the biggest disadvantage might be the timing and conflict issues, due to needing multiple X10 operations from AHP to accomplish the proper switching sequence, as opposed to the hardware-based equivalent action done by the XM adapters themselves - which I believe occurs with only one X10 transmission (not sure).  AHP control also probably would slow down the switch-over somewhat, but a bigger worry might be potential malfunction due to X10 collisions from the multiple controllers (assuming that the camera control interface is in use concurrently in a system with other X10 controllers).  I guess the worst case would be if a camera "off" command got trounced, then the subsequent "on" command for another camera would turn on the second camera while the first one was still on, scrambling the video signal.  And with my luck, that would happen right when something critical needed to be captured on the video!  :-[

HA Man:

--- Quote from: bkenobi on June 14, 2016, 11:04:35 AM ---Although it would be nice to have DC adapters that were directly X10 addressable, I don't personally think modifying one that is speced to low would be the best solution.  I'm not an EE, but it seems to me that it would be easier/safer to just use an appliance module with a relay (as Brian suggested) rather than taking a chance at violating the ratings and having insurance deny your claim for the house you burned down.   :o

--- End quote ---

Well, if we bring potential insurance quibbles into the equation, then we probably would need to avoid a lot of things beyond X10 devices, modified or otherwise...  ::)

But yes, intentionally overloading a device sure is a good way to get into trouble.  I didn't intend to imply doing that.  The requirements of this application demand ~12vdc power capable of delivering several hundred milliAmps, but the highest current rating that I'm aware of for an XM adapter is 200mA, with most XM models rated for only 80mA.  The XMs are also unregulated, so the voltage varies from upwards of 25-30vdc (no load) to about 10-12vdc at their full rated current load, making them a less-than-ideal source of a DC control signal for any devices that are "finicky" about their applied DC voltage - like some relay coils.

I believe that Brian's suggestion was to use an SSR (or relay, implied) on the output of an adequate-capacity conventional DC power adapter, with the XM module's output used as the on/off control signal to that SSR or relay.  That scheme would not involve an Appliance Module at all, and also would need no modifications to the power adapters themselves.  That is a reasonable approach, IMO, but does require custom add-on circuitry, that involves some circuit design and physical construction and packaging of the relay circuitry.  (Even that could give an insurance company some "quibble room"... ::))

As you say, it really is unfortunate that no XM adapters have adequate rated current capacity... and it's also very unfortunate that X10-addressable DC power adapters are not currently in production.  That functionality would be handy for many applications.

The fact that the XM devices (or some equivalent) are not in production also makes it somewhat questionable to design any "system" that relies on them - due to the eventual inability to get replacements, if needed.  That's one reason why I'm fishing for ideas that accomplish the XM functionality using some other (in-production) devices... and one reason why cobbing-up custom circuits also is somewhat risky in terms of maintenance.

Bottom line, it's why I'm sort of "holding out" for a more "off-the-shelf" solution for this application, rather than just diving into some custom add-on circuit or other modification.

bkenobi:
I was just saying messing with the internals of the power supply could be bad if that puts A/C to the outside of the enclosure unintentionally.  I have modified several of my X10 and non X10 devices, but I am wary of modifying the PSU beyond replacing components 1-for-1.  If I were an EE and knew what the components were for, then I'd feel more confident in making such changes.  The insurance bit was really just saying that since I don't know the potential issues I may cause, I don't want to have to try to justify causing a fire hazard with the argument "cause the internets..."  :'

HA Man:

--- Quote from: bkenobi on June 14, 2016, 05:21:07 PM ---I was just saying messing with the internals of the power supply could be bad if that puts A/C to the outside of the enclosure unintentionally.  I have modified several of my X10 and non X10 devices, but I am wary of modifying the PSU beyond replacing components 1-for-1.  If I were an EE and knew what the components were for, then I'd feel more confident in making such changes.  The insurance bit was really just saying that since I don't know the potential issues I may cause, I don't want to have to try to justify causing a fire hazard with the argument "cause the internets..."  :'

--- End quote ---

Doing things that expose people or equipment to hazardous voltages certainly is neither wise nor desirable.  I don't believe that any of the ideas here - other than the one to control a "neutered" Appliance Module via an XM Power Adapter - involved any sort of modification to the innards of any of the power adapters or modules (which is a big plus, from my perspective).

Being unfamiliar with the circuitry of the Appliance Modules, I was surprised to learn that their circuit common is tied to the hot side of the AC line.  In that case, if it was desired to "inject" the DC power output from the XM module into the Appliance Module as an on/off control signal, then probably an opto-isolator would be needed - to protect the XM module... and the user.  Actually, the use of an opto-isolator would have the additional benefit of eliminating the issues caused by the unregulated nature of the XM adapter's output.  Hmmm...

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