Handheld meter robustness testing

[joeqsmith]

Howardlong took the time to put a video together for me showing how the cover is removed.  He struggled at the same point at Dave but then shows the two internal latches.  This is going to be a big help in another week.

[joeqsmith]

Looking at the continuity feature and how to interface with the Gossen using it's built in Bluetooth interface.  I also attempt to compare the temperature drift of Gossen with my most temperature stable meter, the UNI-T UT181A.  Yes, that's right.  UNI-T nailed it on this.

[Wytnucls]

Comparing a top of the range 300,000 count meter to a 40,000 count middle of the road Chinese DMM. 
Wait till you get hold of a 1,200,000 count Gossen 30M, for something really juicy! (16hr battery life, sipping 100mA on idle)
Bluetooth here is meant to be used for short periods, to observe readings at a distance (Android app), not 24hr logging.
The meter has a 300,000 data point internal memory for that task and external power connector, if required.
The final log can then be quickly uploaded to the computer via BT, USB or USB BT.

Influence of temperature on readings outside of the usual 21~25C band is documented:
Was the meter within specs?

[joeqsmith]

The 30M was discontinued so I doubt I would ever do anything with one.  The Ultra is what they list for its successor.

It is interesting how temperature effects the Ultra compared with the Chinese made UT181A.  I think the 181A had about half the battery life after running it for 18 hours.  One thing I did not mention in the video that may not have been clear.  I was sampling both meters every 2 seconds.  Checking the CEM DD-9939, it sends data once a second by default. 

This thread is a meter review and as such, looks at all the features of the UT71D. What I use the meter for is irrelevant.

Good point. I am not suggesting how anyone use the meter.  This Gossen may make a good meter for someone who never needs to use the relative mode or never needs to be near it. Or at least be aware of I've shown in the video at least 12mV of error.  I guess you could run it remote from the Bluetooth interface if it only needs to run for a short time.  But again, to your point that's all irrelevant.  I am just showing the data I collect.   

I am not sure if the meter meets spec of not.  If Gossen ever decides to respond, maybe they could enlighten us.  Holding the temperature within a couple of degrees, 12mV of error on the 300mV range is not real great no matter the excuse.  I won't disagree that the meters I use for a comparison may very well be considered middle of the road, they are certainly more stable when it comes to getting near the meter or running a sweep on them. 

For the few of you who are not interested is seeing the Gossen get ran, the best thing to do is just don't watch.  I'm certainly not on a witch hunt.  For those of you who voted to see a Gossen ran, I hope you are enjoying it.

There's more to come.  I have a few more non-destructive tests I want to do, then we will have a look at the inside and maybe do a little reverse engineering.   As always, if you have a test you would like to see ran, feel free to ask.  Often people will ask a question about a meter I looked at not realizing that very few meters survive or are repairable. 

[joeqsmith]

Part 4

[jordanp123]

I've gotta say I'm surprised at the Gossen so far (Not that I'd heard of them before EEVBlog), they are held in high esteem but it seems like from these tests its nothing special.

[Wytnucls]

Read the manual. None of the Gossens have a Peak mode, except for the Gossen Energy. Testing a feature that doesn't exist. 
Why don't you test the Auto Hold mode of the Brymen?
Not on a witch hunt? When the pigs fly.

No meter does everything. That's why it is important to read the spec sheet and have a range of meters to cover all bases, or at least cater for your limited needs.
I think a Peak mode is useful, if only to work out the crest factor, but for some reason, Gossen thinks differently.

[P90]

I've gotta say I'm surprised at the Gossen so far (Not that I'd heard of them before EEVBlog), they are held in high esteem but it seems like from these tests its nothing special.

these "tests" are purely for entertainment... I wouldn't base any decisions on them whatsoever...

[exe]

these "tests" are purely for entertainment... I wouldn't base any decisions on them whatsoever...

I disagree. Anyway, feel free to propose your tests.

[rsjsouza]

these "tests" are purely for entertainment... I wouldn't base any decisions on them whatsoever...

I disagree. Anyway, feel free to propose your tests.

Same here. When you see the meters failing at somewhat midrange through the voltages, the interpretation one can make of Joe's tests leave a lot of wiggle room in terms of comparison. However, when one fails at the edges it gives you much more to think - especially when a random unit fails with a simple spark.

[jpb]

Read the manual. None of the Gossens have a Peak mode, except for the Gossen Energy. Testing a feature that doesn't exist. 
I think a Peak mode is useful, if only to work out the crest factor, but for some reason, Gossen thinks differently.

The Gossen does have a Rapid Momentary Value Acquisition mode with data store so can capture (close to) peaks I guess but not a simple peak mode.

[Wytnucls]

That would be a feature worth testing. Seems unique to the Ultra and the Energy. Not a proper Peak mode, but may be useful in some circumstances. The Energy DMM has both features. It even calculates the crest factor.

[3db]

I find Joe's tests very informative.
The tests are applied fairly to each product and give a reasonable view of each meter tested.
I think he should be applauded for the time,effort and MONEY he puts into this project.

THANK YOU JOE 
3DB
 

[joeqsmith]

Part 5 of the review for the Metrahit Ultra.   

[TheAmmoniacal]

So what's next? The Gossen is more susceptible to ionizing radiation? More inaccurate in low-gravity environments? Unstable readings while being accelerated?

Joe don't like the Gossen 

Lots of fun.

[Paul Moir]

Would it kill them to pulse the relay at power on?

[ProBang2]

Sorry, the DMM works correct.

It is set to "Auto Power off" after 10 Minutes.
For logging it can be deactivated in this menu.
Or set to a different time.



Aside of that:
Clearly it has big problems with shielding and a lack of customer service...   

[mmagin]

So thats why nobody else uses relays in handheld meters
It's certainly conceivable that in industrial use similar magnetic fields sould be experienced.

Really enjoying the extensive review.

[Fungus]

So thats why nobody else uses relays in handheld meters
It's certainly conceivable that in industrial use similar magnetic fields sould be experienced.

That would be dangerous in a lot more situations, eg. if you threw it in the back of a pickup then drove across the farm*.

A couple of tests:
1: Does the reading flip if you connect it up to the mains AC then slap it around a bit.
2: Does it combust if you connect it to mains AC then use the tape eraser on it?

(*) Germans would only ever throw it in the back of an S-class Mercedes so I can see how they'd miss that one during the design phase.

[2N3055]

I wonder if you can flip the relay into the 'wrong' state by bashing the meter.

That is exactly why bistable relays are a no go in certain high vibration equipment.
If you find the right force vector direction, even a not so strong tap on relay will do..

All mechanical relay are sensitive, but regular ones at least auto reset to right position after the influence is removed.
But if you put that tape eraser nearby any smaller signal relay, it will go crazy..
Reed relay would have real fun ....That is why they many of them are magnetically shielded.

[Wytnucls]

Scaremongering again.
The meter passed all electromagnetic requirements for multimeters.
Just don't take it with you for your next MRI scan and mind those tooth fillings too... 
 
Electromagnetic Compatibility (EMC)
Interference emission EN 610326-1:2006, class B
Interference immunity EN 610326-1:2006 EN 610326-2-1:2006

Americans can't make well engineered meters either. The Fluke 185 and 867B, just to name a few, also have relays.

[P90]

Scaremongering again.
The meter passed all electromagnetic requirements for multimeters.
Just don't take it with you for your next MRI scan and mind those tooth fillings too... 
 
 
Electromagnetic Compatibility (EMC)
Interference emission EN 610326-1:2006, class B
Interference immunity EN 610326-1:2006 EN 610326-2-1:2006

Americans can't make meters either, the Fluke 185 and 867B, just to name a few, also have relays.

:-D

[Fungus]

Scaremongering again.
The meter passed all electromagnetic requirements for multimeters.
Just don't take it with you for your next MRI scan and mind those tooth fillings too... 

It would have to be a hell of a magnetic field to flip the relay from more than foot or so, yes.

Americans can't make well engineered meters either. The Fluke 185 and 867B, just to name a few, also have relays.

But ... does Fluke pulse the relay at power-on to make sure it's in the correct state?

If so, that's a huge difference. Arriving at a site and not knowing if the reading will be correct because you hit a pothole on the way over is slightly worrying.  If I owned one of those and worked on remote sides I'd be switching to Ohms mode every single time from now on. Either that or switch to the industry standard Fluke 87 or 28 (actually more likely than switching to Ohms mode every time).

We need joe bash the meter to find out how easy it is to flip the relay manually.

One problem: He likes to quantify things and "slapping" is unscientific. I can't wait to see the machine he invents for this. 

[3db]

Scaremongering again.
The meter passed all electromagnetic requirements for multimeters.
Just don't take it with you for your next MRI scan and mind those tooth fillings too... 
 
Electromagnetic Compatibility (EMC)
Interference emission EN 610326-1:2006, class B
Interference immunity EN 610326-1:2006 EN 610326-2-1:2006

Americans can't make well engineered meters either. The Fluke 185 and 867B, just to name a few, also have relays.

WTF does Germans /Americans have to do with it ?   

[Wytnucls]

No pulsing on the Flukes.

NAIS relay:
g force:
50g functional   100g destructive
Vibrations:
10-55Hz 3.3mmx2 amplitude functional
10-55Hz 5.0mmx2 amplitude destructive

Pothole won't do it. Empire State building maybe.