EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: PetrosA on February 01, 2011, 12:28:19 am
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My new toy arrived today! I haven't had a chance to get photos of it taken apart yet, but they'll be along soon.
First observations
It's nicely packed and comes with basic test leads (interchangeable tips), a K thermocouple lead w/adapter and four AAA GP batteries. It kinda struck me as odd that it doesn't come with a case since it's intended for field use.
I loaded the batteries and turned it on. The display is much bigger and the backlight is much better than on my U1211A clamp meter and the extra digits in the display make an impression right away ;). Having read about the warning flashes and beeps for when you plug into the A or mA/uA range in a non current mode that was one of the first things I tried out. Well... I don't know if it was because the meter was still cool from transport or what, but it locked up in that mode and neither cycling the power or reseating the batteries helped. It was only after I took the meter apart to check for damage or loose bits (none found) that it started working properly again. I'm also not sure what method it uses to detect which terminal has a probe plugged into it. After getting it working again, I started making some test measurements and it's definitely way faster to settle on readings than the U1211A clamp. For AC voltage they differ by ~ 0.2V which I thought was a pretty good result for the clamp.
I haven't been able to get the scale function to work in mA range with a current clamp yet, but I probably am not doing it right. I'll keep fiddling with it.
Speaking of the mA and A range, there doesn't seem to be a setting to make it default to AC for these ranges which strikes me as odd considering who the meter is intended for. What's more, once you reset to AC and try to use another function like max or peak hold, it jumps back to DC while min/max/average simply wouldn't work for me in AC mode. Again, I'll have to fiddle with it some more, but it doesn't seem like it should be that complicated to set up such a basic (for electricians) measurement.
One other test I did was to see if in LowZ mode it would trip a GFI (RCD) outlet while measuring between hot and ground (PE). It did, but it also freaked the meter out again somehow (it didn't quite freeze this time but it wouldn't read voltage) and I had to restart it to get it to measure voltage again.
I suspect that some of the odd behavior I've had may be related to the cheapie batteries since it's already showing two out of three markers on the battery indicator with less than an hour of usage. I'll be playing with it and using it at work over the next few days and I'll write more and get some photos up ASAP.
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(http://www.my8thgen.com/forums/images/smilies/this_thread_is_worthless_without_pics.gif)
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(http://www.my8thgen.com/forums/images/smilies/this_thread_is_worthless_without_pics.gif)
Ok ok. Gimme a minute ;P
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I suspect that some of the odd behavior I've had may be related to the cheapie batteries since it's already showing two out of three markers on the battery indicator with less than an hour of usage.
Can't be the batteries. If the unit is not showing "low batt" or some such then the unit MUST meet it's spec and operate correctly. You'd at least expect that of brand name instrument ;D
Assuming of course it's not faulty.
Dave.
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here is the ad picture for everybody...
(http://www.transcat.com/images/Photos/U1272A.jpg)
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OK, somebody had to ask, and I'm a little surprised I'm the first... how's the continuity test? Fast? Slow? What is the approximate frequency of the tone? Loud enough?
Also, is the backlight ON by default? BTW looks like a beauty! GREAT PICS!
Waiting for the OLED version...
Mark Z.
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OK, somebody had to ask, and I'm a little surprised I'm the first... how's the continuity test? Fast? Slow? What is the approximate frequency of the tone? Loud enough?
Also, is the backlight ON by default? BTW looks like a beauty!
Mark Z.
The continuity seems fast enough to me, but it failed the Amelia test - my 2-1/2 year old taps the leads too fast for it to react ;) There is a choice of 3200 Hz, 3491 Hz, 3840 Hz, 4267 Hz tones and flashing backlight as well as a programmable ohms limit. A similar warning (with on-off beeping and backlight) can also be set up for a "dangerous voltage" point between 1-1000V to warn you. It also will come in handy for remote monitoring of voltage while troubleshooting. No wireless screen needed!
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Photos are superb. Very well made too. More performance tests, please. Thanks for all your good work!
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Nice pictures.
The unit looks well designed and built, BUT with that in mind, I am disappointed to see self adhesive foil screening applied to the case. I am not a fan of self adhesive foil screens and prefer either laminated foil or metal sheet screening attached to the PCB securely and with a low impedance connection (not a helical spring). Self adhesive foil belongs on Blue Peter along with sticky backed plastic (a UK in house joke).
If it does the job I suppose there is no great problem but if the adhesive lets go at any time in the future you can end up with conductive foil floating around inside the case :o
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Someone stated in another thread that they were afraid to take the case apart on their U1272A. Here is how you do it:
You need to remove the four screws in the bottom half of the backside of the case (two at the very bottom, two in the battery compartment). Then lift the case from the bottom up at an angle to the top to release the two plastic tabs (visible at the very top of the back half of the case in SDIM1692.jpg). Once these are free, you can lay the back half down to the left of the front half and release the piezo leads. There are three small black screws on the PCB. Only the one at the bottom (above the input jacks) is holding the board - the other two hold the LCD in place. Once that is out you can start lifting out the PCB starting at the bottom and working the jack sleeves out first, then there are two plastic tabs on the sides on the PCB near the top of the meter that must be pulled away from the board one side at a time to release it from the front part of the case. The rotary switch is locked into the front part of the case so no need to worry about it falling out.
I didn't include photos of the board under the LCD out of laziness (bad boy...). There's an NEC part under it but I don't know what it's for. If enough people would be kind enough to send me a dollar, I might find the motivation to take it all apart again ;)
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Here is continuity test:
BTW where is the micro processor, under the LCD ??
[youtube]6Y6IX2N3F4AAgilent U1272A visual continuity demo[/youtube]
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Re: the request for performance tests...
I would like to ask for testing suggestions since in my world of AC power there are no cut and dry standards to compare and I don't usually think in those terms. I can compare 50 DMMs and still never know which is showing me the most accurate reading of the mains voltage. The same holds true for the typical resistance measurements I make. Today I installed floor heat and had to verify that the cable and temperature sensor met specs. The cable is supposed to read ~37.5 Ohms while the sensor can read from 8k to 12k Ohms at 20-30 degrees celsius and of course the ambient temp was 18.6 and my reading was outside the published values ;)
So any suggestions would be welcome!
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Regarding the video showing the continuity function. There is no sound on this clip. The continuity certainly looks good on the bar graph, but I wish I knew if I could really hear the thing. Even if one has decent hearing (which I don't) a wimpy continuity tone can get lost in a noisy environment, even in a shop, much less in an industrial setting.
Mark Z.
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There is no sound on this clip.
I did an comment about it ( no sound ) on youtube ,and another one too, and he disabled the comments function.
Some people never do anything with the right way .
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PetrosA , what about replacement fuses , does the manual has any info about them.
Or pointing an source about getting some ?
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If you have an old DMM to compare it too, you can do some basic tests, but if you don't have one, your readings won't have any reference point, whether the reference is better or worse. Using both DMM alternately compare:
Measure a DC battery to the maximum number of digits
With usual care, Measure the AC main voltage, maximum number of digits
Measure its frequency
Measure any resistor, already at room temperature
Measure the current through the resistor, using the DC battery you have above. Is there any difference between what is measured and what should be using ohms law?
If possible and being extra careful, measure the AC current
If you have a function generator measure sine waves up to the rated frequency, what is the frequency response. Compare both DMMs to test the TRMS functions. If you have an oscilloscope, compare the RMS reading against the Vpp appearance. If you have a scope, compare the readings against a square wave and note the TRMS reading against Vpp.
If you have any capacitors at hand, measure those.
These are at least, some of the essential basic electrical measurements. Without knowing who has better and realiable specs, the least you'll know is one meter is different from the other. If the Agilent comes with a calibration certificate, then we know its the better meter, and so now it tests how different your other DMM is compared to a NIST traceable one.
Re: the request for performance tests...
I would like to ask for testing suggestions since in my world of AC power there are no cut and dry standards to compare and I don't usually think in those terms. I can compare 50 DMMs and still never know which is showing me the most accurate reading of the mains voltage. The same holds true for the typical resistance measurements I make. Today I installed floor heat and had to verify that the cable and temperature sensor met specs. The cable is supposed to read ~37.5 Ohms while the sensor can read from 8k to 12k Ohms at 20-30 degrees celsius and of course the ambient temp was 18.6 and my reading was outside the published values ;)
So any suggestions would be welcome!
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Regarding the video showing the continuity function. There is no sound on this clip. The continuity certainly looks good on the bar graph, but I wish I knew if I could really hear the thing. Even if one has decent hearing (which I don't) a wimpy continuity tone can get lost in a noisy environment, even in a shop, much less in an industrial setting.
Mark Z.
Have revisited the U1272A and recorded with sound.
[youtube]GtfZ3rerWE4[/youtube]
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The beeper is indeed quite loud. And for those who wonder, the meter does come with a full calibration report showing the deviation and the equipment used for the calibration.
I compared this meter with my 2000 count manual ranging 50 Euro piece of crap, and on the DC ranges it matches up quite well. On AC the Trms bandwidth goes to 100Khz and the frequency measurement makes it to 1Mhz (outside spec) but at 1Mhz the voltage reading loses it's touch with reality :P. The measured values match up with my analog scope (taking in to account the inaccuracy of the scope).
Basically I performed al the mentioned tests and the values seem to be right to me, I will not post up a table with values compared because A) I'm very busy at the moment and B) the equipment used to compare the meter to are very likely to be less accurate than the Agilent.
I assume the Agilent is more accurate then my 50 Euro cheapie, and the cal report supports that assumption.
So if anyone has got another accurate meter maybe the could compare them, that would make for a better comparison.
@PetrosA, thanks for making clear how the meter should be opened!
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I also think the beeper is quite loud, but without any way to measure, that remains a very subjective observation. I can say that it's loud enough that when I took the photos for this thread at night, in the basement, I turned off the voltage alarm because I was afraid that it might wake someone up on the second floor.
I will try and set up some experiments to compare readings of at least three meters and if I can borrow something else I'll up that number. I don't have a function generator or scope, so that range of testing is out of my league.
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Kiriakos-GR - I removed commenting due to a whole parade of dickheads whining, complaining and insulting me. That clip was made in a hurry for someone who wanted to see the continuity function at work.
Yea , any way the parade of dickheads was correct about whining & complaining .
Because you had not set the video as not-public , and with out an name that will attract anyone.
And so if you care to correct things , rename it from Agilent bla bla to "Video response to my friend John" .
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That pretty much summarizes it, there little more to do other than ergonomics.
The beeper is indeed quite loud. And for those who wonder, the meter does come with a full calibration report showing the deviation and the equipment used for the calibration.
I compared this meter with my 2000 count manual ranging 50 Euro piece of crap, and on the DC ranges it matches up quite well. On AC the Trms bandwidth goes to 100Khz and the frequency measurement makes it to 1Mhz (outside spec) but at 1Mhz the voltage reading loses it's touch with reality :P. The measured values match up with my analog scope (taking in to account the inaccuracy of the scope).
Basically I performed al the mentioned tests and the values seem to be right to me, I will not post up a table with values compared because A) I'm very busy at the moment and B) the equipment used to compare the meter to are very likely to be less accurate than the Agilent.
I assume the Agilent is more accurate then my 50 Euro cheapie, and the cal report supports that assumption.
So if anyone has got another accurate meter maybe the could compare them, that would make for a better comparison.
@PetrosA, thanks for making clear how the meter should be opened!
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I calibrated my monitor tonight and saw how pink the pics were so I redid them :)
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and the rest...
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Great pics and run down on the meter PetrosA.
I noticed somebody mentioned fuses for it. They look like the same fuses (and rating) that are fitted to my Agilent DMM (U1252B.) So just in case your interested, you can get them from Agilent direct. I got two spare sets for my DMM and IIRC they only cost me about £14 total for two of each.
orb
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Great pics and run down on the meter PetrosA.
I noticed somebody mentioned fuses for it. They look like the same fuses (and rating) that are fitted to my Agilent DMM (U1252B.) So just in case your interested, you can get them from Agilent direct. I got two spare sets for my DMM and IIRC they only cost me about £14 total for two of each.
orb
Thanks orb, that price sounds pretty reasonable. Hopefully with the obvious warning the U1272A gives off when the leads are in the current terminals, I won't be blowing any fuses any time soon... Plus I probably wouldn't use the probes but a clamp.
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Great pics and run down on the meter PetrosA.
I noticed somebody mentioned fuses for it. They look like the same fuses (and rating) that are fitted to my Agilent DMM (U1252B.) So just in case your interested, you can get them from Agilent direct. I got two spare sets for my DMM and IIRC they only cost me about £14 total for two of each.
orb
Thanks orb, that price sounds pretty reasonable. Hopefully with the obvious warning the U1272A gives off when the leads are in the current terminals, I won't be blowing any fuses any time soon... Plus I probably wouldn't use the probes but a clamp.
No probs mate ;)
Just one thing to note PetrosA. As I am a hobbyist and didn't have an Agilent account (although I suppose I do now after my order :) ) When I ordered the fuses there was a delay. So I rang Agilent after about 10 days. It seemed they had to ask me a couple of questions in relation to my order, this was so that the info could be put on a form which had to be filled in (by them.) The form was apparently some sort of agreement confirming I wouldn't be using my new DMM fuses for any sort of terrorist activity etc :o. Perhaps the fuses had to come from the US or something, although they were supoosed to be in stock ::)
The Agilent guys were very helpful though so there's nothing to be concerned over, I guess it's just some crazy security thing they have to check on. A week or so later though the fuses turned up :)
Regards
orb
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The form was apparently some sort of agreement confirming I wouldn't be using my new DMM fuses for any sort of terrorist activity etc :o.
The way things are going around here, soon we'll have to fill out one of those every time we go buy a bottle of plant food. :(
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Here is continuity test:
BTW where is the micro processor, under the LCD ??
Replacement clip:
[youtube]GtfZ3rerWE4[/youtube]
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I took a fresh good read of this thread . :)
Lots of info so to verify them as soon my own U1272A arrives.
PetrosA is there any information as model revision on it , or on the software, like firmware version ?
The one that I will get, comes directly from the factory in Malaysia , so I bet that it would be fresh baked like a cookie.
Oh my , just remembered that also the 28II came direct from the factory of Fluke , also as fresh baked cookie :D
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Kiriakos, the only revision number I saw was 004 (board marked as U1271-26500). I haven't tried to look for a firmware number in the menu anywhere, but that doesn't mean it's not in there someplace...
I also got the IR cable so I'll be testing that out for datalogging and hopefully sometime soon will get around to posting a user experience review of the meter and accessories. One thing I will say about the datalogging is that the software is a mishmash of USB to RS232 virtual port which slows things down and forces you to choose a port each time you start the software and connect the meter (at least on my Asus EeePC netbook...). The little bit of time I spent with the software so far was not very impressive and a new, more powerful version would be very welcome.
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I will ask the question no matter what ( if sounds as silly ) ... :) did you download the latest version ( 2011) from their web site ?
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I have version 1.2.1.0 downloaded a few weeks ago. As far as I can tell, it's the latest version.
I had a free day today plus a power outage from lightning, so I had some time to play with the software a little bit. Here are some observations:
- Getting the meter connected is finnicky and doesn't always work the first time around. This is because of the virtual COM port.
- I can't get the software to see both readouts. This may be some configuration problem, but I would think the software should automatically display whatever secondary reading I have set in the DMM.
- The minimum sample interval is one second - much slower than the DMM can read. Booooo.
- You can present the data either as a list or as a graph. The list format is ok, but I don't use it. The graph format is easier to read for customers but has one major problem i.e. the timestamp for the graph format is only given in seconds since sampling starts (0-...), not as hh:mm:ss. This is not useful for me at all, since many times what I need to record is voltage output with a timestamp to show someone from the power company what problems a customer has on site. No one is interested that I sampled for 600 seconds - they want to know what time it was.
- The graph can only be exported as a .bmp file which means that it can only be as large as I can get it on my netbook screen. It would be way nicer if the software could create a .pdf with the graph in vector format so that it contains all the points in the log, as well as being scalable with full resolution. The second best option would be to have a standard, large size for outputting the graph in bitmap form, but I'd seriously prefer the .pdf option.
Here's a sample of the graph output from my meter, as large as I could get it on my netbook. It would look pretty crappy at this resolution if I tried to print it out in landscape on A4 or letter sized paper...
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The list format is ok, but I don't use it.
I think their lies your problem. Export the list data and post-process it, e.g. with Excel, gnuplot, Scidavis, gaw, or whatever floats your boat into a nice graph.
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... Export the list data and post-process it, e.g. with Excel, gnuplot, Scidavis, gaw, or whatever floats your boat into a nice graph.
Well... I've heard of some of those programs ;) The only software I'd know how to use to make a graph would be a vector illustration program, and that wouldn't be automated. If there were an easy way to do this with a script or something, I'd be happy to try it - otherwise, it's beyond my realm of abilities :(
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PetrosA, is it possible to upload an saved data logging event from the DMM to the computer ?
And see if the recorded sample rate was any faster ?
For your information, I just found that Chauvin-Arnoux has also an similar DMM with the same communication system (DMM PC),
I have the feeling that all of them, are using the same software .. (compatible)
Unfortunately the Chauvin-Arnoux software , is not available for download , so to test with it, the Agilent . ;)
Look the attachment .
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On a second note , it looks that the Agilent software called as Basic edition.
This gives room so to speculate, of the existence of the Advanced edition too.
( Call your friends about it, and find out the truth)
Here is an picture of the interface .
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(http://img220.imageshack.us/img220/6326/interfaceoj.jpg)
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On a third note :D
I think that I have good news, just installed the software, and found on the settings,
that other that 1S minimum timing , you can set it also to 0 (zero) if you enter the value manually with your keyboard.
The software accepts the setting and saves it , but I have no DMM to test what happens .. ;)
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oh well it looks that I was very optimist .
Agilent should had an sticker over the range switch with the message:
READ FIRST the 168 pages in the manual BEFORE USE
Like the F16 planes , with the yellow Key tag : Remove before Fly
On topic :
1) The Data logging it is limited to 1 Second intervals ..
2) The collected data format, does not help with Date time descriptions
( check the image at the bottom )
Section Retrieving saved log
3) There is an work around, so to find the Time of when an specific value occurred.
Only by the use of Data logging recorded with PC connection.
(The idea about to manually inspect 10000 records , on the DMM screen it is a joke, even to think about it.)
And so :
You write down in a paper the time that you started the data logging .
Example 10:31:00 am .
And you ADD to this number the additional seconds from the entry that you are looking !!
Example :
The Log entry A00010 was recorded at 10:31:10 am
The same work around works also for the graphical presentation,
like the picture that you had posted above.
Ok I admit it , the Data logging is not practical to use,
with this device + software combo ,
but you have an way to log something. :)
My final word could be , that the Data logger is not the strong point of the U1272A .
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Sounds like Fluke has the better solution for data logging, at least with the 180 series (I expect the 280 series to be better), which was the original target of the U1270 series. It does store time stamps with each data point, and will only log a new point if the value changes. This is especially useful for rare phenomena (eg. once per day the mains voltage drops due to a large load switching on). I think it also registers the min/max/avg at each point. Unfortunately you have to buy a $$$ Fluke 280 series meter to get that these days.
Agilent's solution sounds very simplistic to me, like how it was done thirty years ago, or how a student would implement it.
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On a third note :D
I think that I have good news, just installed the software, and found on the settings,
that other that 1S minimum timing , you can set it also to 0 (zero) if you enter the value manually with your keyboard.
The software accepts the setting and saves it , but I have no DMM to test what happens .. ;)
The logging software is indeed lacking.
If I manually specify a zero in the "seconds" field the software will poll at a faster rate. On my machine I would get about 5-6 samples per second using that setting (Quad core @ 2.8 w/ baud rate of 19200).
PetrosA: FYI, To get it to log the secondary display values, click the "Secondary" button on the "Data Logging Table" tab. Note that this will reduce the number of samples per second that you get when you are using the "0" seconds setting. Also, it will log to file. You might just import that into Excel/OpenOffice and build your own charts with the X-axis showing the date/time.
It's strange when you use the secondary display via their software; when I want mV on primary and frequency on secondary, it forces a reversal and has the unit display frequency on the primary and mV on the secondary. Not sure why this is.
A simple COM port loop in software at 19200 seems to show the value updating at 100 millisecond intervals (image Datalog2: timestamp in milliseconds+reading).
You could use the following commands and roll your own datalogger if you feel the urge:
*IDN? = Unit Identification. Returns Model/Serial/FW version (e.g. Agilent Technologies,U1253A,MY11110011,V1.20)
CONF? = Setting for primary function (e.g. "VOLT:AC +5.00000000E+00,+1.00000000E-04")
CONF? @2 = Setting for secondary function (e.g. "FREQ +1.00000000E+02,+1.00000000E-03"). Returns error (*E) if secondary not enabled.
FETC? = Return value for primary function (e.g. +7.15881000E-03 )
FETC? @2 = Return value for secondary function
Note these configuration commands are examples and you can't override the actual selector switch on the unit (i.e. You can't set it to TEMP when it's on AC)
CONF:VOLT:AC = Configure Voltage for AC
CONF:PULS:PDUT = Configure PW/Duty cycle
There are more of these, I just haven't recorded all of them.
LOG:AUTO xx = Read internal auto-log postion xx value
LOG:HAND xx = Read internal manually logged position xx value
SYST:BATT? = Battery status (e.g. +3.51933000E+01 not sure what units this is in)
Note that I have the U1253A so I don't know if all the commands are valid on the U1271A, though I'd imagine they are the same except maybe the valid range for the LOG commands.
Take care,
John
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Hello John , thanks for posting your findings ..
With your findings , my speculation looks that it does work,
and this is a great find . :D
Well yesterday , I did an very in-depth reading of all the manual.
( so to find every detail about the U1272 and compare it with what I own )
I did check your graph (No1), and it looks that you got there as Max, three sample rates per second.
At this point I like to say, that I do Not see things like to be a race or something.
The data logging are a similar process with the Min/Max/Average function.
And found lots of details mostly from Fluke users manual about it .
It looks that Fluke and Agilent agree , that in the given time of 250uS ( between of any taken sample),
the result are reliable.
In faster sample rates , the possibility of an error grows by some percentage .
Fluke are very clear that at Min/Max/Average there is an 100mS rate, and 250uS at Peak/Min/Max/Average,
(I just found how to get in there yesterday )
:)
And now I know that I must use Peak , when I need maximum reliability .
Unfortunately Agilent has no details at all about the Min/Max/Average sample rate ,
All that it says is that at their own Peak function, the sample rate are also 250uS.
There is no need to say , that your findings about the Com port speed,
its an great info .. 100mS .. that's great , and so the connection speed gets out ,
from the equation of the negative factors. ( Does not slowdown things ) ;)
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People I need a favor , some one to send me by email ,
few files measurements by the data logger.
So to load them on my software and play with it ..
(examine the potentials of the software )
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I have my secondary set to measure temp in Celsius but I can't seem to find any way to get that info in the software (temp doesn't show up as an option in the list). I don't really need secondary to show up in either the list or graph forms, so it's no big loss and since graph resolution is dependent on how large the graph is displayed on screen, I have all the other windows/displays/graphs closed anyway. The only things I'd really like to see are a timestamp on the graph and a vector based graph output. I use a netbook at work which is weak at best, let alone if I need to have multiple programs opened to deal with data files just to create graphs. With the save function they use now I could just as well do a screen save and crop it to email a customer or print out. Seems pretty lame for a 97 MB download ;)
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I had watch before few hours an Agilent Video about bench top multimeters,
they throw the data to Excel ... and from it you can do miracles ( about graphs ) 2D 3D what ever.
That's why I need test files , so to explore all the potentials.
By the way from the images posted from John , there is time stamp and date ..
Is there a problem about time stamp only in the temperature logging ?
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I have my secondary set to measure temp in Celsius but I can't seem to find any way to get that info in the software (temp doesn't show up as an option in the list). I don't really need secondary to show up in either the list or graph forms, so it's no big loss and since graph resolution is dependent on how large the graph is displayed on screen, I have all the other windows/displays/graphs closed anyway. The only things I'd really like to see are a timestamp on the graph and a vector based graph output. I use a netbook at work which is weak at best, let alone if I need to have multiple programs opened to deal with data files just to create graphs. With the save function they use now I could just as well do a screen save and crop it to email a customer or print out. Seems pretty lame for a 97 MB download ;)
Note that the normal "temperature" display on the meter by default is not actually the secondary display of the unit. It's just a convenience display of the ambient temperature at the time and is not available for logging (that I know of). If you want to log temperature, you have to set the unit in temperature mode via the mode switch.
I really thing the best bet for your purposes is to log to a file and then produce a graph with some other program. The log file can be considered your "vector" file and can be scaled & labelled however you see fit.
Take care,
John
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John thanks allot for the files .. You are my hero :D
Here is the temperature of your coffee cup , plotted to Excel..
Now I need a good sleep . ;D
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I've not read the whole thread yet, saving that for tonight!
But with the Uni-T DMMs (I'm looking at a slightly lesser 61E/C) can I set it up to log for 12 or 24hours solid?
Ideally I'd like to log some appliances in my house over that period to work out there consumption. Water cooler, pc, TV etc.
I think I can set it to not turn off automatically after 15 minutes so should be safe, but can it hold that much data? Will the battery last that constant use?
Thanks!
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Ideally I'd like to log some appliances in my house over that period to work out there consumption. Water cooler, pc, TV etc.
That is not a good idea. You will miss the phase by just measuring current, and these cheap meters can't do more than that. Maybe more important, often these cheap meters have measurement duration restrictions in the current range, like measure for no longer than five seconds and then let the meter cool down for a minute. You know, cheap meter manufacturers usually don't care about safety. If they put a warning like this in the manual they really mean it.
If you just need the sum or average over time then get some of these electricity usage monitor. Even the one with that stupid name (What was it? Kill-a-fart? Something like that ...) should serve you better in this case. The simple ones are affordable consumer products. I have seen one or two such electricity usage meters with data logging capacity, too. But these were expensive. Maybe the price has come down in the meantime.
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Awww yeah, forgot about that :( thanks for the reminder!
http://www.reichelt.de/bilder/web/xxl/D100/UT61C.jpg (http://www.reichelt.de/bilder/web/xxl/D100/UT61C.jpg) looking at a nice high-res pic there it's the first time I've seen it state '15minutes between use' as well!
I'll do it with a series of point measurements instead, maybe one of those wall meters is worth a look. I'd love to log the whole house power here, but old has has too much hidden wiring!
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DMMs are great for spot checking current draw, but not long term monitoring of amp-range currents. As BAW says, the cheap ones may have safety issues. Even the higher end stuff typically has a required cool-off period. Hopefully in the expensive meters the issue is not safety, but the accuracy of the shunt resistor over temperature and the fuse lifetime but I wouldn't count on it.
For more serious AC power monitoring a current clamp meter is the way to measure current draw. For power, you want a kill-a-watt meter or similar which will give RMS voltage and current with real and apparent power, plus the integrated energy/average power draw. Higher priced units will also give you things like crest factor, harmonic content, and phase difference.
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Just got one of these from ebay (open box), everything work perfect except ZLOW, with no test leads it shows 6.5V AC, DC is 0V...
???
They should install display with better contrast (its to dark) and make that switch have better feel (like old Triplett meters :))
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Z-Low defaults at the range 1000V AC .... in this range there an indication of 4.7V in my unit.
The True RMS IC controller cause a minimum leak.
Some manufacturers compensate this minimum leak with software tricks, some others do not.
The Fluke 28II reads 2V ( 1000 ACV range) and by it self it zero out this reading in 5-8 seconds.
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Mine shows 7.5-8.5V in ZLow mode. Like Kiriakos said, it's because it uses the 1000V scale and doesn't do correction. Once you connect it to a voltage source, it will read correctly. Nulling mine seems to introduce offset error.