Uni-T UT805A 5.5 digit bench multimeter - pre review questions

[willd1971]

Hi guys,

I'm selling various Uni-T (Uni Trend) equipment on my website www.labtronix.co.uk.  I'm planning to do a review of the UT805A, their absolute top of the range bench multimeter for you to look at (and then maybe crave ).  But before I set to it please let me know what kind of things you want to see and see measured and tested.  Key features I can see are functions, data logging, PC software interface, what's included, and what's inside.  Looking forward to hearing from you!

William
www.labtronix.co.uk

[Bored@Work]

Because this is a bench multimeter that wants to play with the big boys

- Accuracy, especially how serious they are about their claimed  +/- (0.006% + 2) DC accuracy *cough* *cough*

- Quality of the parts (electrical and mechanical)

- Quality of the build

- Safety of the instrument

- What A/D Chip(s) and voltage reference?

- Does min/max work? There was a batch where this wasn't the case.

- Is the meter really remote controllable (accepts config commands from the PC), or is only readout of measurement values supported?

- Especially because it is a Uni-T 80x, does it double as a lunch box, like its smaller brothers 803, 804?

And of course the usual stuff, PC software (how rubbish is it?), interface protocol spec. available, calibration procedure spec. available, probe quality, display quality, ease of use, quality of the manual, ...

What not? Please no unboxing or endless "what is in the box". A three second action shot is enough. Watching paint dry is more interesting than unboxing.  We all know how a cardboard box, a kettle lead, a CD, etc. look like.

For bonus points, how similar is the enclosure form factor to that of typical Agilent meters? I.e. is it properly stackable together with other instruments of the same form factor from other vendors.

[mjlorton]

Certainly all the points that BoredAtWork has noted and:

* Display update speed
* Continuity speed
* PC software data update speed from the UT805A to the PC
* Can the PC software log data on the PC real time...are there any limits on duration and intervals? Can it be exported i.e. CSV?

Cheers,
Martin.

[willd1971]

BoredAtWork Your first point is the tough one, I think this would be my disclaimer at the top of a review, I have no equipment suitable to verify the claimed accuracy - but I might be able to do something with incremental resolution and stability.  Any suggestions are welcome.

All your other points will be no problem, I hope...

William
www.labtronix.co.uk

[BravoV]

Definitely lots of close up photos on the components on the complete teardown, and take as many angle shots as you can.

Imo, people here are quite demanding.

[vk6hdx]

Looking forward to seeing this review William, and like B@W also wondering if there is enough room to put my sandwiches and morning snack in there like the others in the series. 

[alm]

BaW: where did you find the 60ppm spec? The information I found indicates 0.015%, which is somewhat mediocre for 5.5 digits.

Some additional points:
- How's the viewing angle and contrast of the display? This meter uses an LCD while most competitors use a VFD. Try to compare to a well-known reference, like a Fluke 87V.
- How convenient and intuitive is the UI (controls, menus)? I know this is a subjective issue.

The protocol appears to be documented in the user manual, that's a pro.

[Bored@Work]

BoredAtWork Your first point is the tough one,

I know, but these figures are what people really pay for, except, of course they just want to have something for posing. Unfortunately UNI-T is not a brand people can trust blindly when it comes to specs. 

BaW: where did you find the 60ppm spec? The information I found indicates 0.015%, which is somewhat mediocre for 5.5 digits.

Edit:
I have seen that meter specified with the mentioned +/- (0.006% + 2) DC accuracy (http://www.uni-trend.com/UT805.html), but also with +/- (0.015% + 4), i.e. two times worse.

Oh, shit, the A version indeed seems to have half the accuracy of the original 805. On really can't trust UNI-T even with their model numbering ... And it looks as if the A version has an LCD now, no longer a VFD.

And yes, should the later be true, then +/- (0.015% + 4) is questionable for a 5.5 digit meter. Already the percentage-of-reading accuracy indicates that the last digit is mostly pants. And that is assuming UNI-T keeps its word. And it is unlikely that the thing is still good as a transfer voltmeter, because UNI-T doesn't specify short-term accuracy at all.

[alm]

Really? They downgraded the specs when going from the UT805 to UT805A? That's horrible. Maybe the original spec was wildly optimistic and they changed the specs to be more realistic after getting complaints? Although that doesn't explain why the would replace VFD by LCD, that would be just a cost-cutting measure.

I'm also impressed by their web presence. There is no English Uni-T website about this product, only some vendors selling it and a manual on some third-party website. The manual is the usual Engrish job with gems like 'Under the short-circuited REL status'.

The input impedance spec is also strange. Some sites, like Labtronix, quote > 1 Gohm up to 2 V DC, but the manual claims > 500 Mohm. Some seller on Alibaba even claims 10 Gohm. Was the original spec 1 Gohm but did they figure out their assembler was unable to meet their leakage specs?

From the figure 17 on page 40 of the manual, there definitely appears to be space for at least a snack, though maybe not your whole lunch .

[Bored@Work]

Really? They downgraded the specs when going from the UT805 to UT805A?

It looks like they did that. The 805 web page specifies +/- (0.006% + 2), and the 805A manuals says +/- (0.015% + 4).

That's horrible.

Yup. It is not what honorable men do.

Maybe the original spec was wildly optimistic and they changed the specs to be more realistic after getting complaints?

Could be, they downgraded the specs from wildly optimistic to optimistic  .

What I don't know is if they also adjusted the price. I vaguely remember that the non-A 805 was rather expensive. While the 805A is in the 450 Euro range.

Although that doesn't explain why the would replace VFD by LCD, that would be just a cost-cutting measure.

Cost is one possible issue. Another one could be if they changed the chipset to one with a (cheaper) LCD-only driver. That could also be a reason for the downgraded specs.

I'm also impressed by their web presence. There is no English Uni-T website about this product, only some vendors selling it and a manual on some third-party website.

Many Asian companies don't get this or just don't care about anything outside Asia or China, respectively. E.g. Owon recently released a programmable power supply. Last time I checked there was no information about it on their English site. I could just find some fragments on eBay. Rigol also doesn't have complete information on their English website. 

The input impedance spec is also strange. Some sites, like Labtronix, quote > 1 Gohm up to 2 V DC, but the manual claims > 500 Mohm. Some seller on Alibaba even claims 10 Gohm. Was the original spec 1 Gohm but did they figure out their assembler was unable to meet their leakage specs?

The original, non-A spec was 1 GOhm for the 200 mV and 2 V DCV range, and 10 GOhm for the other DCV ranges.  I think just throwing the dice for the 805A gives better results than trusting any paper.

From the figure 17 on page 40 of the manual, there definitely appears to be space for at least a snack, though maybe not your whole lunch .

Oh dear, then a Mars bar has to do

[willd1971]

Hi guys,

I'm quite daunted by the discussion that I've sparked up.  Not just for the UT805A that's naked on my bench right now (oh yes, I've already seen what's in the lunch box!!!), but can I possibly live up to your expectations and give you what you want?

Regarding the spec information on my website (Labtronix), that's just a cut and paste from the Uni-T website so there may well be some errors to be worked out.  This process will try to get to the real beast.

It may be a few days before I'm ready to report back.

William
www.labtronix.co.uk

[Hydrawerk]

Any opinions or reviews on UT805A?
I am afraid that the LCD display with crap blue backlight might not be well readable. Most manufacturers put a VFD there.

[tszaboo]

I was crying during that video. Thanks for sharing. Does anyone know, why did they put time and date on that horrible screen?

[Hydrawerk]

Does anyone know, why did they put time and date on that horrible screen?

Because they want more features and it looks modern,  LOL.

[Wytnucls]

The Min Max values and the 100 data points are recorded and recalled with a time/date stamp. This information is displayed in the screen 'time and date' location. Most users will want an accurate time and date to start with, hence the constant display.

Calibration is fairly easy, but needs an external accurate reference for all ranges.

[Shock]

Review spoiler alert

[Richard Crowley]

There IS actually space for your lunch in that "lunch box"!  So essentially all the functionality is in the volume of a typical hand-held meter.
DSO makers have progressed beyond the old CRO form-factor. But I guess you need some amount of "volume" in order to stack test equipment on the shelf.

[CrashO]

Any opinions or reviews on UT805A?

You can get a Rigol DM3058E for about the same price (about 60 bucks more). Easy decision for me   

[MartyD]

Man, that looks really nasty inside! And they seriously want to charge €400 for this... thing!

[mcinque]

Review spoiler alert

That THING is priced €400?  Absolutely ridiculous!

[Yago]

Time lord technology doesn't come cheap!
Cost much of the asking price to make the insides larger than the outside!

[PChi]

Having just blown a couple of hours probing high impedance signals with a cheap mulitimeter and getting spurious readings probably due to mains hum pick up I vote for checking the Common Mode and Differential Mains Hum rejection at 50 and 60 Hz. It's really important. Fluke specify it for the 87V in the Detailed Specifications for example.

[nidlaX]

Review spoiler alert

Necroing this thread: did anyone here ever get this unit for a full teardown? I don't know if Shock was trying to make a joke, but that's obviously not the meter in question...

From the same Polish forum post:

[Alfons]

Thera are two different Versions: UT805 and UT805A. The "empty-box"-one is the UT805A.

[nidlaX]

Thera are two different Versions: UT805 and UT805A. The "empty-box"-one is the UT805A.

The "'empty-box'-one" is the UT804 series or less, which are basic "handheld multimeter in a benchtop case" multimeters that have nothing to do with the UT805 series. The UT805 has a VFD while the UT805A has a graphical LCD. Both are 5.5 digits.