Are Little Transformers Energy Pigs?

Surge protectors do not consume electricity when they are always on line (at least, not enough to matter). Devices with light touch power pushbuttons do consume energy but how much depends on the device. They need the electricity to provide power to the power circuitry (I'm using too much "power" here ) to switch on the device when you press the button.

Personally, if the standby current consumption is not specified in the device manual, I'd use a clamp meter to measure the current draw when everything is off. Then, you can calculate the kwh consumption from that.

If you don't have a clamp meter, either borrow one or determine the standby consumption by patiently watching your house's electric meter when nothing's running.

If all those little transformers (xfmrs) are and/or feel warm/hot whether the item they are powering is on or off, it's consuming electrical energy and converting it to heat! So...It will help you heat your home with expensive heat in winter and requires additional cooling to cool your home in the summer. Not unless you have hundreds of xfmr's plugged in, could I see it making a major impact on your electrical consumption. But every little bit helps.

The total input wattage would be listed on the xfmr. This would only be required if the piece of equipment being served requires the the maximum. With the xfmr idling, the loss would probably have to be measured.

Surge protectors don't use electrical energy.

Were's my "That was easy buttom?" Damn that button....it's never around when I need it.

Let's take a guess and say 1 watt per wall wart. Let's say on average every home has two. I'm guessing in the US 100 million homes for 200 megawatts of power doing little to nothing 24/7 or approximately 8,760 mega-watthours per year of pure human convenience.

Sounds like someone should invent a controller, which can switch off the transformer when the device is off, using back-up battery for the remote circuitry.......

It has been done. It is called a switch. Use an AC plug strip with a switch and turn them off when not in use. It has worked well for me for many years.

Switches are fine where you have easy access to the socket, but where these are hidden it becomes a problem.

There is also the situation where you are in the conscientious minority, and development of an automatic system would save energy without the general population knowing.

Have you ever heard of motion detectors or switches activated by sound? I would not be surprised if you could find sound activated switches programed to your voice.

These will consume a small amount of power while they are switched on in order to monitor for the event that they are intended to respond to, so these are another good example of an "energy pig", as in the poster's question.

My intention was to use a small PIC controller, as power consumed in standby mode is measured in microwatts. Connect to a relay (showing my age here!), and program to switch on transformer when "on" signal is received from remote. This can then also shut off power to the transformer when the device is put on standby.

Thus, the user still has the convenience, but uses virtually no power when device is inactive.

Remarkable.

So simple, I'm surprised it's not already out there - or is it?

It is. Here is a link to a company that sells remote controls and the actuator uses a piezoelectric system to generate the energy to transmit to the AC unit. No batteries to replace. I made a passive infrared motion detector that interfaces to the actuator and will run for years off of a lithium coin cell or two AA cells but it will probably never be marketed.

http://www.prestostore.com/cgi-bin/pro17.pl?ref=lightningonlineorder1867&rdf=go

For some things, a switch is fine, and I simply unplug many of the transformers when not in use (my cellphone and other battery chargers for instance), but it is way too much trouble to turn off and then back on in correct sequence my DSL, the wireless router, the computer, etc., so those are on 24/7.

That leads me to your previous post: If you include the TV (Which I haven't turned on in a couple of months, but is still blinking because I haven't set the time since the last power outage) I have at least 5 transformers plugged in within a couple of meters of where I sit. I know that not everone has as many goodies as I, but I have no game devices and I also bet that many of those who have fewer, also don't bother to unplug any of them. I suspect that a more accurate guesstimate would be closer to 6 or 8 per household.

Another device known as "Latching-Relay" which is made by a pulse [not continuous current] & breaks by next pulse. ie a Door-bell push-switch can switch it on by pushing it once & breaks when pushed again

From what I've seen around the web everything that has step-down transformer type power supply consumes power all the time. This would include computer monitors, and CPUs that the actual main power switch is left on (if it even has one, most monitors don't.) This also includes TVs (those with remotes that can turn on and off consume a bunch in stand by mode, I assume the same for just about any remote device that is continuously listening for a signal from the remote.) Wall warts are picked on more often because we can see them and feel the heat they put out when we touch them. Yes all of these things are consuming power; most likely it is less than a dollar a month. Some households with many of them (i.e. several teens each with own cell phone, ipod, etc.) could be more.

Theoretical transformers are modeled with a simple energy balance, i.e. energy in = energy out. If there is nothing drawing power from it (example cell phone unplugged from charger cord, but wall wart still plugged in) in theory there would be no energy going in. Unfortunately no transformer is 100% efficient especially the cheapies that they send out with consumer crap with a life exp. of 2 yrs. So they consume power even with the other end of the cord (low voltage) is unplugged.

http://en.wikipedia.org/wiki/Standby_power

http://en.wikipedia.org/wiki/Power_supply

In response to the comment I'm replying to that calls for an invention that will automatically switch off the transformer when not in use: Just throw that chunk of copper out of the whole design and use a switching power supply.

http://en.wikipedia.org/wiki/Switched-mode_power_supply

These are much smaller and lighter and instead of consuming a max of 1w in standby mode they consume only a few milliwatts. They actually switch from the mains at high speeds (>20KHz, typically in 100KHz range and up) to step down the voltage from 120VAC or 220VAC and also provide rectification at the same time. They control the output voltage by adjusting the "on time" of the switch or controlling the "duty cycle" this is called Pulse Width Modulation (PWM). This concept can nearly remove the need for a step down transformer. Instead inductors may be used to help caps filter the DC output to reduce ripple.

There is more reason for these. The wikipedia page shows AC, half bridge rectified, and full bridge rectified voltage diagrams. What they failed to show is what a filtered full bridge waveform looks like. Instead of seeing the full sine wave, only the front side of the crest as the filtering caps charge and an exponential decay as they discharge through the load. One should recognize from this that the device is only drawing power (allowing electrons to flow) for a very brief period near the crest of the sine wave. Granted, these devices make up a very small amount of the total load on the grid. (Let's not get into freq drives as they do a similar thing and make up a good share of the load) However, since all of the power is sucked off the crests of the sine wave they introduce a very unsmooth current and voltage profile that distorts the AC sine that the power plants try to drive out. This pulse type loading can cause harmonic ringing in power transmission transformers and even all the way back to the windings in the generators. Switched power supplies can pull power off the line at any point along the sine wave as long as the voltage is significantly greater than the desired output. Many devices are running 3.x volts and the rest use 12, either way the line voltage is well above those levels for a vast majority of the time. To go on in theory it is safe to assume that there is no way all of these devices on the grid would be in the ON part of the PWM cycle at the same time, this is because they are clocked by a digital controller instead of grid freq.

---------------------------NOTICE---DISCLAIMER---------------------------------

All of the above information should be considered hoopla as the author most likely has no clue what he is talking about.

One way of determining the energy consumption is to disconnect everything in the house and confirm the watt-hour meter on the incoming supply is stationary. Then, connect and energise the devices one wants to assess. Note the time and the reading, and go out for a few hours. Upon return, note the time and the reading. The energy consumed over the time expended gives an idea of the consumption.

Generally, if it runs warm, and it's not in use, turn it off.

In theory this could work. However, if you want to measure a device that may only be drawing one watt, it could take 1000 hours to move the one's digit (kwh's) by one click.

While undoubtedly true, it may be that such a rate of consumption is a low priority consideration.

And that's why we have so many of them running all the time. As a boy I got in a big fight with my dad (depression era guy) about the VTVM I left on 24/7 to keep it stable. I did the calculation for the electric it used per month at the rate of 15 watts and offered him a quarter to cover the cost and then some. He just went of grumbling.

Quite. On an individual household scale the effect is small. On an aggregated global scale the effect is significant.

You're lucky ... it would cost me $2.16 / month for 15 watts 24/7!

15 watts x 24 hrs/day x 30 days/month x $.20 kWh (yes, 20 cents per kWh).

These things add up because there are so many of them, although they are more typically in the range of 3-10 watts.

If you are attempting to run a house off-grid (although in that case you would probably have far less of these "parasites") these small, but 24/7 loads are a major drain on batteries, especially because people forget to factor them in when sizing back-up battery power capacity.

For a surprise, add up how many electronic devices you have that draw power 24/7 when not being used: Every TV, VCR, DVD player, cordless phone charging cradle, electric garage door opener, rechargeable electric toothbrush, Dustbuster charger, answering machine, any charger of any type you leave plugged in, cable (or DSL) modem, router, etc, and multiply by a very conservative average of 4 watts: I think this is a major "hidden" problem today, in terms of wasted energy and expense.

Greg

Quote:

I think this is a major "hidden" problem today, in terms of wasted energy and expense.

Very true.

Thanks for your comment about off-the-grid folks. One of my freinds lives off the grid with a small bank of 12v batteries. Likes to watch a little TV (they had one from the grid days) so they use a small inverter (probably inefficient on its own) to power it. He found out right away that the TV consumed enough power over nite to run his batteries down before morning. Even if it was "turned off" all day; solar panels can keep up with it during the day, but after the sun goes down so do the batteries. He learned that he had to unplug it otherwise in standby mode, searching for signal from remote, it drawed way more power than he could provide. The inverter seams to consume very little power if it's not supplying any power.

An additional item: anything that plugs in that tells the time. It is pointless in having N devices plugged in that tell the time; if two of them disagree, then which of them is "right" (rhetorical question)? One would be better off disconnecting N-1 of them.

For your amusement....

I had access to a report on Grid Load Statistics in the 1960s from New York State, USA.

The report concluded that 4% of the power consumed was electric clocks. That, if I remember correctly, was based on about 3 to 4 watts motor/clock.

THANKS FOR SEMICONDUCTORS.

Just a mathematical correction to my "conceptual" formula:

15 w x 24 x 30 x $.20/(1000 Wh/kWh) = $2.16

When I did the math, I just "automatically" moved the decimal point .

Sorry for any confusion that may have resulted.

Greg

This is a very rough guesstimate but it will give you some sort of idea how much energy these power packs consume.

Each power pack will have the output given in volts and amps and sometimes watts as well. If they do not have the watt rating multiply the output voltage by the output current.

Transformers are roughly 80% efficient so the loss will be about one quarter of the rated output of the transformers. Therefore

Power_Loss = Power_Rated x 0.25

This figure will give you a rough idea of how much power that a plug pack will consume when connected to the mains but not in use.

Here is an example where we have a 12 V 900 ma plug pack and the cost of electricity is 13 cants per kilowatt hour.

Power_Loss = 12 x 0.900 x 0.25 = 2.7 watts

Cost = 13 x 10.55 ÷ 1000 = 0.0351 cents per hour or roughly $3 per year.

Vulcan, in post #1 stated;

"Surge protectors do not consume electricity when they are always on line (at least, not enough to matter)."

This is true for most protectors but when the items connected to them are drawing power they do. It depends on how the protect and the level of protection they provide, but they can use up to 25% more energy than the device by itself. The cheap filters will consume 2-5% all the way up to a double shielded ferro-resonant transformer at 25%.

Here is an example of the additional cost of using a line filter that pulls 15% more power with a 400 watt load that is used for 4 hours a day with the same cost as above

Coas_Added = Hours_Day x 365.25 x Power_Rated x 15% x Price_Electricity

Coas_Added = 4 x 365.25 x 400 ÷ 1000 x 15% x $0.13

Coas_Added = $11.40 per year

These are pure guesstimates but they will get you in the ball park and give you some sort of idea how much money you are wasting each year.

masu,

I 'm a litle fuzzy on power calculations, but I don't see where you get 10.55 (Cost = 13 x 10.55 ÷ 1000) from. Can you explain?

Thanks,

mycoman

Mycoman gets the gold star and goes to the head of the class for noticing the deliberate (well that's what I am claiming) mistake.

"I 'm a litle fuzzy on power calculations, but I don't see where you get 10.55

(Cost = 13 x 10.55 ÷ 1000) from. Can you explain?"

I must apologize mycoman. I have inserted the wrong number somehow. The 10.55 should be the 2.7 Watts from the previous line. The final result is still the same however so when I did the calculations I had the numbers correct I just transposed them incorrectly.

The line should actually read

Cost = 13 x 2.7 ÷ 1000 = 0.0351 cents per hour or roughly $3 per year.

Sorry about that folks, I have not the slightest idea where I got the 10.55 from. At least I know that one person out there bothers to read and understands my babblings.

I am puzzled....

The questioner asks about his

"surge protection plugs taking power...."

Surely a surge protection plug is a passive device to capture spikes and noise on the mains supply... They shouldn't be taking any power unless a spike needs suppressing... don't they?

Or am I missing some important point here? I mean does he mean surge protection plugs or the usual plug top power transformers you are all talking about?

John.

I think he's talking about that wall warts plugged into the surge suppressors, also known as power strips with surge protection...

But I think the OP is long gone by now, probably never to read the thread that we all poured ourselves out on.

You could always buy one of these;

http://www.sustainabilitysystems.com/products.php?cat=8&gclid=CNzLu6GYjIoCFSLiYAodC0dseg

It will give you a very accurate kWH measurement over what ever amount of time you want to test for. Then you can spend another x$ to buy timers or pic controllers to turn the wall warts off. Of course, if your timer or pic controller is to work, it needs power!

When it's all said and done, you could conceivably save almost as much money as you spend trying to save it!

The main issue is that these things should be more efficient.

For one reason or another, it is simply not practical to disconnect many of them: cordless phones, electric garage door openers, etc

DonnieH:

This in reply to ur query, all transformers and other devices kept idle on line with the load does consume power, this depend on the current rated by the manufacturer on the device in Idle state.

So to stop wastage, u shall require to switch Off all such devices not in use.

regards

p.sengupta India - Hyderabad

Quote: *************

GM1964 Member Join Date: Jan 2007 Location: Edinburgh, Bonnie Scotland Posts: 17

#15 In reply to #14 My intention was to use a small PIC controller, as power consumed in standby mode is measured in microwatts. Connect to a relay (showing my age here!), and program to switch on transformer when "on" signal is received from remote. This can then also shut off power to the transformer when the device is put on standby.

Thus, the user still has the convenience, but uses virtually no power when device is inactive.

Quote Ends : *************

But you forgot that the RELAY will hold the device only by drawing CURRENT as long as the device

remains ON.

There is another Group who is working hard to save Energy to Protect the Forming of Hole in Arctic Space

http://www.localcooling.com/signin/

Haajee,

I believe what GM1964 means is that the PIC is connected directly to the main power line of the house. The PIC controls a relay that, when switched on, will provide power to the transformer of whatever device he wants to switch on. In this configuration, the relay will be OFF until switched on via the remote control. Therefore, only the PIC will be drawing current.

Vulcan, you are correct!(almost)

The PIC would run off a rechargable battery, or a button cell. This could be recharged automatically while the device is on.

The comment behind the reference to a relay was intended to suggest that I also know that more modern electronic switching could be used which uses minimal power, but most people will know what a relay is/does.

Excellent idea! With a PIC, the drain on the battery would be very small then, lasting several months perhaps? 'Wonder if anyone's doing this already. 'Seems like one of those ideas that people ought to have thought about years ago.

PIC ??? Whatit means?

If you use "Self-holding relay" which is held magnetically by a Pulse & released by a pulse, the it is OK

Haajee,

PICs are a class of relatively simple microcontroller chips that are used in many applications and products where a more sophisticated microcontroller is not necessary to handle the level of logic required.

Greg

From the discussions here, I think it is safe to assume that we all agree these pervasive devices can be made far more efficient by factors of hundreds at least so that we would be talking of "off state" power consumption in terms of only tens of milliwatts, instead of watts. There is no need in particular for electronic devices such as TVs, VCRs, DVD players etc, to use their main (large) power supplies to maintain standby features with the tremendous inefficiency this imposes in terms of power actually needed to power consumed.

Greg

There is one point that nobody has discussed and that is that if electronic equipment is going to fail it will almost certainly fail during the power up sequence. There reasons for this are complex but it comes back that when the power is applied there is a high inrush current that stresses the components and reduces their life expectancy.

A classic example of a device that will fail prematurely due to power cycling is a hard disk drive. If you keep them powered up they will last much longer than if they are powered down periodically. There is a different mechanism at work here but it is an example of how cycling the power can damage the equipment.

By continually turning off and on electronic devices you are reducing their life expectancy and the added cost due to premature failure may offset the cost of the few watts of power that is saved by turning the equipment off.

This has nothing to do however with the fact that those plug packs that are left plugged in with no load will waste energy I am just pointing out that with many devices it you can shut down the power side and leave the electronics running you can increase the life expectancy of the device considerably. When you take the extended life expectancy and energy required to manufacture and carry out repairs it may not be worth the few watts of power saved by turning the device off.

Another point to keep in mind is that some devices, for example video recorders, are sensitive to moisture and have in build heating systems that are designed to stop condensation. By removing the power completely, especially in humid environments, you may end up causing damage through condensation.

It just some thoughts but it shows, like everything, when you look at in detail it always turns out far more complex than you would have initially thought.

Hi (again) Masu,

While I agree that some devices suffer on power-up, I respectfully disagree that it adversely affects most higher end devices.

I have always turned off (as in unplugged) monitors and computers, or at the very minimum at times powered down computers (which turns off the hard drives), and never had a problem. In over 25 yrs of computing, at home and at work, on many different machines, usually with multiple hard drives installed, I have only had one catastrophic hard drive failure, one other one that was starting to have sectors go bad, plus one that warned of imminent failure but didn't before I replaced it. Now granted, this is anecdotal evidence, and doesn't prove a thing, but I have never read any study that specifically said it is better to leave things powered up 24/7. If you have any such info I would be very interested, because so many people believe in not even turning off computers and such, just letting them lapse into a standby mode, often with the energy saving power downs of drives disabled.

Having serviced many computers, especially the newer ones, with high airflows, I can attest to the amount of dust that accumulates on fans, and heat sinks. Since I think we can all agree that heat is a major cause of component failure, this has to be factored in also ... the increased dust accumulation caused by leaving a computer on, along with increased potential of harm from power aberrations, including outages and the effects of the utility restoring power.

As to the possible harm from humidity, I agree that can be an issue in certain cases.

The pro's and con's of leaving electronics on or powering them down between uses is a long running debate, and I don't claim to have the answer, speaking as I am from only my own experiences, but any hard facts or comparitive studies anyone can turn up would be appreciated.

Greg

Hi Greg,

"I have always turned off (as in unplugged) monitors and computers, or at the very minimum at times powered down computers (which turns off the hard drives), and never had a problem. In over 25 yrs of computing, at home and at work, on many different machines, usually with multiple hard drives installed"

One of the problem with all modern hard drives is that they do not retract the heads when they spin down. As a result the heads need to land on the disk surface in a special area reserved for this. There is a finite number of times this can be done without the heads suffering to the point that they will no longer fly. The number of times the heads can be landed has been increasing over the years but there is a finite limit.

Another problem is that while the disk drive is spun down the heads are in contact with the disk surface. If left in contact for too long a process called sticktion can take place. This results in a bonding of the heads to the disk surface and when next powered up the heads will be damaged. The period of time that the drives can be spun down and this effect has been improved dramatically but it can still occur.

Any electronic device that has a capacitor in it will have an inrush current. These currents can degrade the junctions of semiconductors and over time the device fails. The more often you start the machine the more the junctions are degraded. This is an accumulative problem like the landing heads in the disk drive.

"Having serviced many computers, especially the newer ones, with high airflows, I can attest to the amount of dust that accumulates on fans, and heat sinks."

This I am in 100% agreement with you. The idea of sucking out the hot air and turning you computer into a vacuum cleaner is one of the crappiest ideas of all time. I build a home automation system based on a 386 back in 1992 if I remember correctly. This machine uses a series of fans that blow filtered and cooled air over the electronics and disk drives. The system has been running 24/7 and still is without ever have a fault. The only time it has been shut down is during power outages and that is less that 10 times in all. Have you ever seen a PC that can claim that sort of UP time?

Another thing that happens and this is something that is getting worse, is overheating after shutdown. When you kill the power all the fans stop immediately so the cooling also stops immediately. The problem is that there is a fair amount of heat left in the system and the maximum temperature that the chips and in particular the micro processor are exposed to is shortly after the system is turned off. Again this is an accumulative problem that slowly degrades the junctions on the transistor.

OK what all this adds up to is a slow step by step degradation of the system and a reduction in the signal to noise ratio. What you will find is that as the machines become older they will start to have problems like disk errors, parity errors and seemingly inexplicable system halts caused by internal buss errors.

Anyway that's a quick summary of my experience of working on the buggers. It really depends on what sort of reliability you want in the long run. I initially came from a control system background so my idea of reliability is 100% with no unexpected failures and this can be achieved with modern computers. Most office applications however will be as happy as a pin in poo with anything better than 95% so all this is academic.

Hi Masu,

I can't disagree with anything you say, but I am not concerned over the possible heat damage at shut down, because I keep my computer reasonably clean, built it with top quality parts, and it has good airflow. At shutdown, I feel the thermal mass of the heat sinks and natural convection will combine to prevent any overheating. As to thermal cycling, you have a point, and I can't disagree, only state that I have never had a problem, and I go for reliability too. Some of the software I use (CAD or high end graphics and/or TV viewing/recording software in particular) can get buggered occasionally (on any machine I have ever used), and I have to shut it down and restart that particular software. Additionally, I will sometimes reboot the system just to start "clean", not because it needs it, but just to satisfy my own preferences. Sometimes, it does need it because AOL which I use at times is a hog of resources, and is not that reliable. XP Pro I have found to be exceedingly stable, but the habit of rebooting on any suspicion, based on experience with older computers and operating systems, dies hard.

I have never had a machine on for more than a week or two: no need, and I retire my machines to only occasional use after a few years because I need more power by then. I used to pass them down to the kids, but with their programs requiring so much power nowadays, that is no longer practical.

I also have a control system background, with PCs, embedded PCs and PLCs.

Your 386 is nothing short of amazing! That's about 130,000 hrs!

Is the HD running or does it power down automatically?

BTW: Did you build the I/O hardware yourself, or use a commercial card or serial device? Also, is it digital only, or 8-12 bit analog also? Do you have any plans or info on what you did?

In any case, like I said I agree with all you say about the hard drives and such, but I am looking for some sort of test results to quantify any shortened lifetimes, not our "in principle" or anecdotal information. Maybe someone can provide that info. Then I could make a better determination on what the trade-offs might be. Right now, I'll stick to my experience because everybody who I know personally who leaves their computer on 24/7 has had problems that I haven't.

This debate has been going on since before the computer, and I don't expect it to stop now, especially since without doubt some devices do last longer if not cycled on and off much.

Greg

OK, I'll have to put in my two sense here. First, from Wikipedia: "In most desktop and server disks, when powering down, the heads are moved to a landing zone, an area of the platter usually near its inner diameter (ID), where no data is stored. This area is called the CSS (Contact Start/Stop) zone. However, especially in old models, sudden power interruptions or a power supply failure can sometimes result in the device shutting down with the heads in the data zone, which increases the risk of data loss. In fact, it used to be procedure to "park" the hard disk before shutting down your computer. Newer disks are designed such that either a spring (at first) or (more recently) rotational inertia in the platters is used to safely park the heads in the case of unexpected power loss." So true it used to be that you had to manually "park" the heads but they figured out that people weren't reliable and that has been fixed. My experience is that even if you get more total run hours by running a drive continually I have had them fail in one year of continuous service where as computers I may only use part of the day have lasted for years.

Hi Greg,

"I also have a control system background, with PCs, embedded PCs and PLCs. "

I got involved with PLCs back in the late 70s when they were just starting to get noticed. I did a lot of work with Struthers-Dunn and was amazed when, a few weeks back, I stumbled across a company that was still selling the Director 4001 series PLCs. Even more amazing was that they were charging roughly the same price for second hand units as we were for new ones back in the 80s. I didn't think there would be any still in existence after a quarter of a century let alone a market.

My personal belief is that PLCs are one of the most underutilized pieces of equipment ever invented. I am not sure but I suspect it has to do with the majority of people not even knowing they exist and those that do not understanding their potential.

Your 386 is nothing short of amazing! That's about 130,000 hrs!

Its been a little ripper, it uses a board which was designed by PR1ME computer and used for controlling UPS for larger computer systems as the primary IO device. It also uses an 8 bit sound blaster and a text to speech program to verbally annunciate numerous things. One of its primary functions was a burglar alarm so it had motion detectors wired to it and could page you if it detected and intruder. This was later upgraded to calling you on a mobile phone and verbally annunciating the fact. Another thing I got it to do was act as an alarm clock. When it was time to get up it would politely announce that it was time to time to arise. Then every 5 minutes with increasing sarcasm it would nag until it detected motion in two separate rooms. There was no way around it, the only way to shut it up was to get out of bed and walk into another room.

Were are about to move house so the system will be dismantled in a couple of months but the next version is going to be considerably more elaborate. The plan is to use a PLC for the real world interface and switching of mains voltages with a PC, probably a carputer, doing the higher level stuff like text to speech and voice recognition.

Is the HD running or does it power down automatically?

The hard disk is kept running at all times and has a separate cooling fan that keeps it considerably cooler than in most PCs. The whole thing is in a purpose built enclosure that is on slide rails in a 19" card rack. The fans that I used to keep it cool are 240 V fans but I have reduced the speed by installing a dimmer switch. This reduces the noise and extends their life considerably. There is a thermostat mounted in the box that can run the fans at full power in the event of it getting too hot.

It's a classic example of over engineering everything to a ridiculous point but as you can see the result is an incredibly reliable system. Being able to talk meant it needed a name, I let you figure out what it was called but it was named after a certain wayward computer from a move about a black monolith.

Hi Masu,

Thanks for the added info. I was picturing an office PC MB, not an industrial embedded version.

"My personal belief is that PLCs are one of the most underutilized pieces of equipment ever invented. I am not sure but I suspect it has to do with the majority of people not even knowing they exist and those that do not understanding their potential."

I couldn't agree more. I came to PLCs much later, in the early 80's, with the GE Series 1. Over the years I have worked with most major brands, and a few obscure ones, but my overall favorites are the Koyo lines. They made models at one time for GE and Siemens, including the GE Series 1 that I started out with. They developed their own distribution under the PLC Direct banner, which, with the addition of many other related hardware and software products is now Automation Direct.

For those readers who may not be familiar with PLCs, (Programmable Logic Controllers) they are generally self contained or modular units that are designed specifically to control things based on inputs and a (your) custom program. The programming software runs on a PC, and the finished program is downloaded to the PLC, where it is stored. At that point, the PLC will execute the program by controlling its outputs based on the inputs and programmed instructions, with no further connection to a PC.

PLCs are robust, small, "inexpensive" devices, ideal for many home automation functions, in addition to their machine/process control functions in industry.

They were originally designed to replace relay logic from the arrays of discrete relays of various kinds that were originally used in "automated" machines. For this reason, they originally were programmed in "relay ladder logic" style, since this was already understood by engineers of the day. Over the years, the programming interfaces (software) included more and more features of higher end programming, but still by and large retain their "relay logic" roots, with built in counters, and drum, time delay, latched, one shot, etc, relay functions.

Some links that describe PLCs:

http://www.plcs.net/chapters/whatis1.htm

http://www.automationdirect.com/static/specs/whatisaplc.pdf

While for most machine applications, I prefer the DirectLogic DL205 line, or a higher, their low end, low cost, DirectLogic 05 line, with 8 inputs and 6 outputs, starts at $99:

http://web2.automationdirect.com/adc/Shopping/Catalog/PLC_Hardware

I too "over engineer" my own personal projects (also to a ridiculous point at times): its fun, and they last "forever". The constraints that apply to commercial products don't apply to our own stuff and we are free to indulge ourselves, not to mention the ability to use some of the "stuff" we may have lying around.

Give my regards to HAL.

Greg

Hi, masu & Greg G

I have started to leave my PC on for longer periods as one HD was making funny noises for the first five minutes after restart. They still wind down (in power saving mode), but reliability of XP does seem to improve the longer there is between updates.

Restarting just after an update is a nuisance, usually needing three attempts. We also have some Macs, and they are shut down daily but have never given any cause for concern.

Its not just computers which can suffer from on/off syndrome. We started using low energy bulbs about 9 years ago. In one location the old bulb (60W - 1000hrs) was switched on & off regularly through the day, and needed replaced every other month. The low energy ones (7W - 8000hrs) take some time to come to full brightness, so have been left on continuously. The current bulb is only the second to be used in that location.

GM1964,

Fluorescent lights in general, but the small electronically driven replacements for incandescents in particular have their lifetimes shortened considerably by being restarted frequently. This is inherent in the starting (arc initiation) methodology used in the bulbs which is a well documented phenomena, and is also related to the quality of the electronics in the energy saving versions.

My own experience with these is similar to yours, especially where higher temperatures are present. My bathroom lights have the shortest lifetime, being turned on and off so often, followed by recessed fixtures in hallways which are turned on and off often, plus are exposed to higher temperatures in the fixtures. The worst application was in an exhaust fan/light unit over the shower and after several replacements, I finally gave up and went back to an incandescent. I suspect that either the slight vibration and/or any electrical spikes from the fan motor were at fault, but I don't know. I discount any factor of humidity, because the bulbs I have installed in outdoor fixtures have no problem.

Greg