Re: [time-nuts] Power Monitoring
Quoth Dennis Tillman at 2008-04-19 11:41... Don't forget that the cable from the DB-9 connector on the back of the APC UPS to the DB-9 Serial Input on the back of your PC is NOT 1-1. For reasons I have never understood the APC UPS requires a proprietary cable that came with the UPS. Even worse, it looks identical to a plain old DB-9 to DB-9 serial cable except for the label on it. I got round this by buying a pair of DIY DB9 to RJ45 shells - in fact that's how I do all my serial cables now, CAT6 in the middle. Pinouts are on the web. Cheers M -- Matthew Smith Smiffytech - Technology Consulting Web Application Development Business: http://www.smiffytech.com/ Personal: http://www.smiffysplace.com/ LinkedIn: http://www.linkedin.com/in/smiffy ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Power monitoring
Hal Murray wrote: My power went out the other day. That reminded me that I've always been slightly curious about that area. Our telescope suffers from flaky mountain power, so we have to do this sort of thing. The problem is sending a message that the power went out to the university campus from the mountaintop over a network that may not be working because the power went out. Many steps of communication depend on UPSes to hold up for a few minutes to get that email out. We have a big honkin' Liebert 40 KVA UPS to run all the telescope's computer systems between when the power dies and the big generator kicks in. It has the nice byproduct of AC mains voltage and current monitoring over RS-232. I expect you can buy a separate box to do this, but it has to be installed by an electrician to read current draw and probably is not cheap due to the required agency approvals. For monitoring whether there is mains power or not, a 110VAC coil relay plugged into the non-UPS outlet tells a computer that there is no mains power. Dirt-simple and reliable unless someone unplugs it or puts it into the UPS outlet. The relay's power cable has been wrapped in red tape and labeled prominently to help prevent tampering. The computer that does the monitoring is on a UPS behind the Liebert UPS, so it will work for a longer while after a power failure. A battery-operated data acquisition system would be better for long outages. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Power monitoring
Quoting Hal Murray [EMAIL PROTECTED], on Thu 17 Apr 2008 11:10:11 AM PDT: My power went out the other day. That reminded me that I've always been slightly curious about that area. Are there any not-expensive boxes made for this? Or something that shows up on eBay occasionally? Lots of dataloggers out there in the $200 range. Check out things like the HOBO from Onset. you can also get embedded style computer from someone like Tern or Z-world or Vesta that has all the hardware needed, and comes with some basic software that you could use. If I was doing it myself, I'd start with a low power (quiet) PC and a UPS. Battery and single board computer or data logger is much better... such an application doesn't need a video monitor, keyboard, etc. Then I'd have a platform that could monitor other things too, like temperature. Step 0 is just to measure when power is/isn't there. I assume the UPS has a signal for that. Step 1 is to measure the voltage. This takes an A/D. The standard PC audio input might be appropriate. no DC coupling on the audio card. Much better to either get something with the appropriate A/D OR a one-wire style interface. You could transformer down the 60 Hz, digitize as an audio signal, and process it appropriately. I'd probably use an AC wall-wart transformer for isolation and a couple of resistors to get down to a reasonable voltage. Step 2 is to catch dips and spikes. That's just software behind the A/D. (assuming the A/D is fast enough) As long as I'm dreaming... Suppose I wanted to measure the power my whole house is drawing. What's available along the lines of a current transformer on the main lines? My first thought is that nobody does that (for homes) so it's probably horribly expensive. On the other hand there is a lot of interest in energy conservation these days so it might only be somewhat expensive. Lots of these available, in the few hundred dollar range.. http://www.powercostmonitor.com/p3982/power_cost_monitor.php http://www.theenergydetective.com/index.html you can also do something like watch the wheel goaround on the meter with a photocell or put a suitable current transformer ($5 surplus, $50 new) on the mains coming in. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Power monitoring
In message [EMAIL PROTECTED], Jim Lux writ es: As long as I'm dreaming... Suppose I wanted to measure the power my whole house is drawing. What's available along the lines of a current transformer on the main lines? My first thought is that nobody does that (for homes) so it's probably horribly expensive. On the other hand there is a lot of interest in energy conservation these days so it might only be somewhat expensive. Lots of these available, in the few hundred dollar range.. The best and likely cheapest solution is to get the data from your utility meter. Most meters have a S0 output which sends a pulse evern X Wh. If you can't find it, ask your power-company for access. Tell them you want to monitor your energy conservation effort and they'll likely not charge you for it. If that fails, search google for gasdims :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Power monitoring
Poul-Henning Kamp wrote: In message [EMAIL PROTECTED], Jim Lux writ es: As long as I'm dreaming... Suppose I wanted to measure the power my whole house is drawing. What's available along the lines of a current transformer on the main lines? My first thought is that nobody does that (for homes) so it's probably horribly expensive. On the other hand there is a lot of interest in energy conservation these days so it might only be somewhat expensive. Lots of these available, in the few hundred dollar range.. The best and likely cheapest solution is to get the data from your utility meter. Most meters have a S0 output which sends a pulse evern X Wh. If you can't find it, ask your power-company for access. Tell them you want to monitor your energy conservation effort and they'll likely not charge you for it. If that fails, search google for gasdims :-) I like this thing http://www.digital-loggers.com/epcr2.html It has two busses, one can be powered by a UPS and the other directly off the mains. You can measure power and voltage on both busses, it has a reasonable web interface, you can turn the outlets on/off from the network. I think it's a deal for $295, but they also have a cheaper model. jeff ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Power monitoring
Quoth Hal Murray at 2008-04-18 03:40... My power went out the other day. That reminded me that I've always been slightly curious about that area. Are there any not-expensive boxes made for this? Or something that shows up on eBay occasionally? Firstly, I'll second the suggestion to use 1-Wire for the environmental monitoring. Resources: http://www.buoy.com/mailman/listinfo/weather 1-Wire weather list. http://www.weathertoys.net 'Weather Toys' - this excellent book describes how to build a 1-Wire weather station. See also the links page on the author's site. My APC UPS monitors line voltage and always tells me when it blips or goes out of range (and by how much). Serial connection to my (Linux) server running apcuspd: http://www.apcupsd.org/ Cheers M -- Matthew Smith Smiffytech - Technology Consulting Web Application Development Business: http://www.smiffytech.com/ Personal: http://www.smiffysplace.com/ LinkedIn: http://www.linkedin.com/in/smiffy ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Power monitoring
You're in luck! Much of what you want to do can be done for almost nothing. Several years ago when I was interested in knowing more about the power coming to my PCs I had a Uninterruptable Power Supply made by APC (American Power Conversion). Most of their models, except for the very lowest price ones, came with the ability to tell you just about everything you could be interested in about the power line voltage through a DB-9 connector on the rear. These models went by the name 'Smart UPS'. The software, provided by APC, was called 'Power Chute'. Any company that made UPSes for servers had features like this and software to go with it. The status of the power line is important for a computer server and an IS manager to know. So, the UPS would report the line voltage at intervals you selected via its built in A/D, the magnitude and duration of all over voltage transients or drop outs, the line frequency, the status of the batteries, etc. In the event of an imminent loss of power the UPS could tell the server how long the batteries would last. Many of these messages had settable limits so you could specify a 'normal' range for each of these events. In addition, for each condition you could specify an action to be taken (email someone, dial a pager number, shut the server down, etc). Lots of interesting things can be found in the logs kept by the UPS software about the status of the power coming into a server. In addition the server could tell the UPS to test itself periodically to verify and recalibrate the charge on the batteries, etc. The batteries in a UPS wear out in 5 years (just like a car battery). Most people don't know that the bateries are easy to replace. You can buy replacements on-line or through a local alarm company. But because the batteries wear out people think the UPS went bad and usually they throw the UPS out or take the UPS to a local recycling station. You ought to be able to find one with the smart features in it for next to nothing. You don't need to have good batteries in it to be able to use the smart interface to start monitoring your power line voltages. Dennis -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Hal Murray Sent: Thursday, April 17, 2008 11:10 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Power monitoring My power went out the other day. That reminded me that I've always been slightly curious about that area. Are there any not-expensive boxes made for this? Or something that shows up on eBay occasionally? If I was doing it myself, I'd start with a low power (quiet) PC and a UPS. Then I'd have a platform that could monitor other things too, like temperature. Step 0 is just to measure when power is/isn't there. I assume the UPS has a signal for that. Step 1 is to measure the voltage. This takes an A/D. The standard PC audio input might be appropriate. I'd probably use an AC wall-wart transformer for isolation and a couple of resistors to get down to a reasonable voltage. Step 2 is to catch dips and spikes. That's just software behind the A/D. (assuming the A/D is fast enough) As long as I'm dreaming... Suppose I wanted to measure the power my whole house is drawing. What's available along the lines of a current transformer on the main lines? My first thought is that nobody does that (for homes) so it's probably horribly expensive. On the other hand there is a lot of interest in energy conservation these days so it might only be somewhat expensive. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Power monitoring
Our telescope suffers from flaky mountain power, so we have to do this sort of thing. The problem is sending a message that the power went out to the university campus from the mountaintop over a network that may not be working because the power went out. Many steps of communication depend on UPSes to hold up for a few minutes to get that email out. Have you tried turning that around? Do the active monitoring from the campus where you have a solid place to stand. If you can't ping the mountain top there is a problem. For monitoring whether there is mains power or not, a 110VAC coil relay plugged into the non-UPS outlet tells a computer that there is no mains power. I like that level of simplicity. Thanks. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Power Monitoring
Quoth Kit Scally at 2008-04-18 11:37... Ah-ha. Now here's the rub! I've got 2 such APC Smart UPS - but I cannot find, beg, borrow or steal a copy of the PowerChute software from anywhere. Does anyone have a copy lurking unwanted unloved in their 3.5 floppy cabinet ? Try here: http://www.apcc.com/tools/download/ (I just Googled for 'Powerchute download'.) I've got a 1.4kVA APC Smart UPS here - got it with new batteries on eBay for about $300 AUD plus freight and quite delighted. (I don't have Windows software for it as I run Linux on the attached server and use apcupsd.) Cheers M -- Matthew Smith Smiffytech - Technology Consulting Web Application Development Business: http://www.smiffytech.com/ Personal: http://www.smiffysplace.com/ LinkedIn: http://www.linkedin.com/in/smiffy ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
