Review of Agilent U1272A

Table of contents

RoadTest: Agilent U1272A

Author: tronixstuff

Creation date:

Evaluation Type: Independent Products

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: Agilent claims that the U1272A is a replacement for the Fluke 87V

What were the biggest problems encountered?: See detailed review

Detailed Review:

[Updated 31/01/11, 20/02/11, 24/03/11, 01/04/11, 14/06/11, 20/06/11, 24/10/11, 23/3/2015]
2015 update - I needed to get new battery contacts fitted as some Duracell AAAs leaked, and Agilent/Keysight won't take my money to pay to get this fixed. An AU$460 DMM is a "throw away" after the warranty has expired. So will drill out the rear and fit my own 6V power supply to it.
Hello element-14 members

A few days ago I happily received an Agilent U1272A all the way from the USA for my testing pleasure. At this point I would like to thank Alistair from element14, Premier Farnell and of course Agilent Technologies. Thank you.

 

The purpose of this article is to initially examine the Agilent Technologies U1272A water and dust resistant digital multimeter. This is an extremely well specifed instrument, and according to the Agilent
promotional material a better alternative to the venerable Fluke 87V. So let's dive in and take a look.

Initial impression

The retail box as always is impressive and well decorated. Opening it up reveals a range of items:

contentsss.jpg


including the meter itself, a calibration certificate and calibration results sheet, probe set, thermocouple, quick start guide and four AAA cells. A carrying case is not included, however it is available from element-14; search for Agilent part number U1174A. For those interested, a full range  of documentation is available here:  http://bit.ly/ewASUg. The meter measures 207 x 92 x 59 mm (hwd) and is quite solid, not too heavy and surrounded by a good orange non-slip rubber layer.  It is refreshing to see that the keypad is laid out in an organised way, much better than the random-looking layout on the U1250 series.

meterss.jpg


The meter

Installing or changing the the battery (four AAA cells) is easily accomplished, and thankfully the fuses are also in the same compartment. The included AAA cells are the
cheaper "GP brand", and should do for the first few months. The dust and moisture protection is evident as shown by the o-ring seal around the perimeter of the compartment:

batteryfusecompartmentss.jpg


As mentioned earlier, the U1272a is water and dust resistant to IP54 specifications - 54 meaning "protected against dust limited ingress"/"protection against water sprayed from all directions - limited ingress permitted.".It is possible to turn the function selector with one hand whether you have the meter standing up or laying on your desk. The included test leads are just over 1200mm in length and are rated at Cat III 1000V, 15A. Two pairs of probes are included, with 4mm and 19mm tips:

 

leadsprobesss.jpg

 


Unfortunatly alligator-clip adaptors nor probes are included - these are very useful especially to those who are colourblind and need to sort resistors or measure tiny through-hole capacitors. Furthermore, a K-tyle thermocouple and non-compensation transfer adaptor are also included:

thermocoupless.jpg


The thermocouple's temperature range is -20~200 degrees Celsius, however with an optional thermocouple the maximum temperature can be increased to 1200 degrees C. AS for the other
measurement ranges, they are:

  • DC Voltage - 300 mV ~ 1000V at 0.05%
  • AC Voltage - 300 mV ~ 1000V at 0.07%
  • DC Current - 300 uA ~ 10A at 0.2%
  • AC Current - 300 uA ~ 10A at 0.6% within a bandwidth of 45 ~ 2 kHz
  • Resistance - 30 ~ 300 M Ohm at 0.2%
  • Capacitance - 10 nF ~ 10 mF at 1%
  • Temperature with K-type thermocouple - -200 ~ 200 (1372 with optional thermocouple) degrees Celsius at 1%

Furthermore there is a diode test  function, and a continuity beeper. The backlight also flashes when using the continuity function which would be very convenient
for those working in a noise environment.

In use

Although readers would not have any problem using the meter without reading the manual, doing so will illustrate the particular features of the U1272A as well as operation of the menu system that allow various settings to be changed. These can include: beep frequency (!), backlight duration, data communication parameters, default temperature units, scale conversion values, and activating the low-pass filter available when measuring DC voltage and current. At the risk of shortening the battery life, I extended the backlight duration immediately to thirty seconds; and set temperature units to degrees Celsius. When taking measurements that only require the main numeric display, the ambient temperature is shown in the secondary numeric display. I must admit to discovering another feature by accident, if the leads are in the current and COM terminals and you select a non-current measurement function - the meter will beep like crazy, blink the backlight and show an error message. This is useful when you're tired and probably should be doing something else...

Measuring AC voltage provides various data upon request. Apart from the RMS voltage value, you can also turn on a low-pass filter which blocks unwanted voltage above 1 kHz.

The frequency measurement function allows the display the frequency, duty cycle and pulse-width when measuring AC or DC current or voltage. Furthermore, you can display both voltage/current and also display the frequency, pulse-width and duty cycle at the same time, for example:

freqvoltss.jpg


Measuring DC voltage is straightforward, and there is also the option to measure both AC and DC components and display them combined or separately, for example:

 

acvoltdcoffsetss.jpg


You can also display voltage as a decibel value relative to 1 mW (dBm) or a reference value of 1V (dBv). And the dB reference impedance can also be set to fall between 1 and 9999 ohms. Another interesting voltage measurement function is "Zlow". Using this function, the meter changes to a very low input impedance, and can remove "ghost" voltages from the measurement by dissipating the coupling voltage. This function can also be used to test if a battery is still usable, if the voltage of the battery under test decreases slowly, it doesn't have the capacity to deliver the required voltage. However I wouldn't put a battery under this test method for too long due to the meter acting close to a short circuit.

 

Measuring resistance is simply done with the U1272A, and for more precise measurements one can short the probes to measure their resistance then set a null point so your measurements will not be affected by probe resistance. There is also an Agilent feature called SmartOhm which can be used to remove unexpected DC voltages that can add errors to resistance measurements. You can also use SmartOhm to measure leakage current or reverse current for junction diodes. I look forward to spending more time examining SmartOhm. Furthermore, one can also measure conductance (the reciprocal of resistance) which is measured in Siemens. According to the manual one can measure extremely high resistance values up to 100 gigaohms. Interesting. The continuity tester is rather well-specified, you can detect for whether there is a short or open circuit.

Diode measurement works as expected, the standard setting displays the voltage drop across the diode. However by pressing Shift on the meter, you can use the "Auto-diode" function which forward and reverse bias simultaneously using both numeric displays. For example, measuring a 1N4004 diode produces the following display, the forward voltage and the Good/Not good result:

autodiodess.jpg


Measuring capacitance is also quite simple, and the manual recommends setting a null value while the probes are open to compensate for residual capacitance. Interestingly the LCD shows when it is charging and discharging the capacitor under test, using the following segments:

 

 

capsegss.jpg

Temperature measurement is possible with the included thermocouple and adaptor. Note that the included K-type thermocouple is only rated for up to 200 degrees Celsius, however with an optional unit the meter can measure up to 1372 degrees C. The display can show Fahrenheit as well as Celsius. The meter also shows ambient temperature using the secondary numeric display when it is not in use with other measurement display functions.

 

Measuring AC or DC current is completed as expected, and as noted earlier when switching to another non-current function, the meter will remind you to change the positive lead.

 

At this point I will finish, as it was written after having the U1272A for six days. In the next few weeks I will update this road test article with more information once more experience has been gained with using the meter in more day to day situations. For those wishing to purchase an U1272A, just click "store" at the top left of the page and search for U1272A.

 

So thanks for reading, and please leave any comments or your questions below.

 

- John Boxall, tronixstuff.com
[Updated 31/01/11]
A question has been left below asking about the speed of the continuity function. Here is a short video clip of it in action -  http://www.youtube.com/watch?v=GtfZ3rerWE4

 

[Updated 20/02/11]

 

Well almost a month has elapsed. A few good things - the battery is holding out nicely, considering I always use the backlight this is unexpected. One very annoying thing however is the autoranging. For example, turn the meter on by selecting ohms, and the display goes all over the place - OL to numbers in the meg-ohms, and all over the place. Shorting the probes doesn't do anything, so you have to turn the meter off and on again. Not happy about that, by the time you get it going it can take 30 seconds just to measure a resistor. Furthermore, the frequency measurement can take three or four seconds to get a reading, which seems rather slow. For example in this video from when I was experimenting with a CMOS 4047, the meter took four seconds to get a frequency - slower than my Fluke 233 or 20 year old Tek CFC-250.
Otherwise it is working well with the other ranges, so time will tell. Stay tuned for next month's update!
[Updated 24/03/11]
Just a followup to the previous notes. The key to using this meter is to have a little patience with the autoranging. Otherwise it has been working without any issues - and still on the orginal battery. Unless anyone has any more questions or the meter does something interesting, this will be the last update. Thanks for reading
[Update 14/06/11]
Agilent have acknowledged errors in early U1272 firmware, and will send a free USB cable out so you can update the firmware yourself. Instructions can be found in this .pdf file.
[Update 20/06/11]
The USB>DMM cable has arrived and the firmware updated to v2.0. Kudos for Agilent for taking ownership of the problem and sorting it out so rapidly.
[Update 24/10/11]
My U1272A had a few issues, however the Agilent Test and Measurement Service and Support team in Melbourne, Australia received the DMM and had it repaired under warranty and returned in a jiffy. Sometimes things do go wrong, but it reassuring to know Agilent will be there to help you out.
Anonymous