Author Topic: U1272A - Yay!  (Read 23808 times)

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Offline PetrosA

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U1272A - Yay!
« on: February 01, 2011, 12:28:19 am »
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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Offline TopherTheME

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Re: U1272A - Yay!
« Reply #1 on: February 01, 2011, 03:42:54 am »
Don't blame me. I'm the mechanical engineer.
 

Offline PetrosA

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Re: U1272A - Yay!
« Reply #2 on: February 01, 2011, 03:51:35 am »
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Offline EEVblog

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Re: U1272A - Yay!
« Reply #3 on: February 01, 2011, 04:23:48 am »
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.
 

Online Mechatrommer

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Re: U1272A - Yay!
« Reply #4 on: February 01, 2011, 04:24:17 am »
here is the ad picture for everybody...

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Offline mzacharias

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Re: U1272A - Yay!
« Reply #5 on: February 01, 2011, 11:03:06 am »
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.
« Last Edit: February 01, 2011, 01:26:55 pm by mzacharias »
 

Offline PetrosA

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Re: U1272A - Yay!
« Reply #6 on: February 01, 2011, 12:19:21 pm »
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!
« Last Edit: February 01, 2011, 12:59:47 pm by PetrosA »
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Offline saturation

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Re: U1272A - Yay!
« Reply #7 on: February 01, 2011, 10:40:57 pm »
Photos are superb. Very well made too.  More performance tests, please.  Thanks for all your good work!
Best Wishes,

 Saturation
 

Online Fraser

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Re: U1272A - Yay!
« Reply #8 on: February 01, 2011, 10:54:55 pm »
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
 

Offline PetrosA

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Re: U1272A - Yay!
« Reply #9 on: February 02, 2011, 02:53:11 am »
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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Offline zaoka

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Re: U1272A - Yay!
« Reply #10 on: February 02, 2011, 03:02:54 am »
Here is continuity test:

BTW where is the micro processor, under the LCD ??

 [youtube]6Y6IX2N3F4AAgilent U1272A visual continuity demo[/youtube]
 

Offline PetrosA

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Re: U1272A - Yay!
« Reply #11 on: February 02, 2011, 03:18:44 am »
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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Offline mzacharias

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Re: U1272A - Yay!
« Reply #12 on: February 03, 2011, 11:05:09 am »
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.
 

Offline Kiriakos-GR

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Re: U1272A - Yay!
« Reply #13 on: February 03, 2011, 11:37:31 am »
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 .


 

Offline Kiriakos-GR

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Re: U1272A - Yay!
« Reply #14 on: February 03, 2011, 11:44:05 am »
PetrosA , what about replacement fuses , does the manual has any info about them.
Or pointing an source about getting some ?
 

Offline saturation

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Re: U1272A - Yay!
« Reply #15 on: February 03, 2011, 11:52:49 am »
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!
Best Wishes,

 Saturation
 

Offline johnboxall

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Re: U1272A - Yay!
« Reply #16 on: February 03, 2011, 12:01:39 pm »
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]
« Last Edit: April 01, 2011, 07:05:34 am by tronixstuff »
 

Offline Floyo

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Re: U1272A - Yay!
« Reply #17 on: February 03, 2011, 04:42:15 pm »
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!
 

Offline PetrosA

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Re: U1272A - Yay!
« Reply #18 on: February 03, 2011, 07:55:48 pm »
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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Offline Kiriakos-GR

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Re: U1272A - Yay!
« Reply #19 on: February 03, 2011, 10:59:25 pm »

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" .

 
 

Offline saturation

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Re: U1272A - Yay!
« Reply #20 on: February 04, 2011, 11:44:19 am »
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!
Best Wishes,

 Saturation
 

Offline PetrosA

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Re: U1272A - Yay!
« Reply #21 on: February 07, 2011, 07:12:40 am »
I calibrated my monitor tonight and saw how pink the pics were so I redid them :)

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Offline PetrosA

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Re: U1272A - Yay!
« Reply #22 on: February 07, 2011, 07:21:07 am »
and the rest...
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Offline orbiter

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Re: U1272A - Yay!
« Reply #23 on: February 07, 2011, 12:16:07 pm »
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

Offline PetrosA

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Re: U1272A - Yay!
« Reply #24 on: February 07, 2011, 01:59:15 pm »
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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