[Edit] Later in this post I am lamenting about the output format not being fixed. That of course is not true, I just cannot count, that's all. See a later post.
[Edit]I also have been mentioning, that the VA mode does not work with the 10A range. This seems to have been fixed as well. Also more in a later post
@HJK:
There was a slight misunderstanding. I have not been primarily referring to you doing this implementation, but more to your statement that the Energy would play with linux. At least with with testcontroller.
But on the other hand, if someone else is supposed to implement it, it would mean that you pass on the documentation. If that does not violate any terms of agreement with Gossen, that's perfectly fine.
I still have a Metrahit Extra, but without that IR adapter, and now that I own the 1908, it eventually will have to go. But if against all odds there is still something I could help out with, just let me know.
I already have a template for my power supply, however, it took me some time to find the part where you can specify more serial parameters. Still lots to learn, but we'll get there.
But thanks for guidance!
@bd139:
In fact it is actually a great little meter. In short, it is the successor to the venerable Fluke 45. The similarities are striking. On paper it may not have the most flashy specs, but to me it excells in usability. YMMV, of course.
The display is top notch. A real gem. And so is the continuity test. Usability is straight forward and the possibility to run of battery is a welcome addition as well. And it is made in UK. Not, that chips with vinegar really go well along with human rights either, but...
In addition I very much like the fact, that it can measure and display volts and amps in one go (limits apply) or alternatively can read AC+DC values and have the pure AC or DC values displayed in the 2nd display. Latter is something some handheld multimeters can do as well, first however is not so common any more and probably has been one of the main selling points for me. With the lack of AC peak measurements being the main point of hesitation.
It does have however have it's fair share of limitations and I can see, why, for it's retail price vs. its features, it does not get any more love. All of those are however very clearly stated in the manual, so you know beforehand.
Accuracy wise it is actually not that bad. For small values it beats the HMC8012 (on paper at least), but it also does lacks a uA or 10mV range. Generally, for sub mA or sub 10mV AC measurements this is not your device - it does not feature a jack for shielding either. Further, it is only specified up to a crest factor of 3. That is rather on the low side.
The 10A range can only be selected manually, which in turn limits the VA function up to 1.2 Amps. This is really an unnecessary annoyance and probably could easily be fixed in software, but I would not hold my breath for this ever to happen. Not an issue with PC reading, you do the calculation there.
As VA is just calculated, no real power measurement. But, contrary to the HMC8012, also works for AC. Since those measurements are done alternatingly, it does not take phase into consideration. Probably the reason Hameg did not implement this at all.
Again, that those measurements are not two independend, parallel measurements, but alternating ones, is clearly stated in the manual. For AC volts and -current in normal/slow mode that comes down to a 12sec coffee break before a reliable/stable reading. All other combinations are fine.
Half the time in fast mode with losing one digit.
It is still faster than my prema with up to 20sec and I am an old bloke, I have time. Given, that this an bonus feature anyway, I have no problems with this at all. You can always measure both units independendly as with all other meters, if you are in a hurry.
Thank to the directly accessible buttons that is way faster and more convenient than having to turn a dial. And having to make sure, the meter does not tip over while doing so. Also, you can leave both cables (current and voltage) connected even while measuring only one unit exklusively and then switch. No warning beeps or shut jacks blocking you. Excellent.
The stats/math functions are implemeted somewhat half heartedly. They only operate against preset values in the menu, not against a set Null value. This does hurt especially for the otherwise rather usefull Delta% function.
Also, you cannot calculate the more practical dBV, just dBm.
As you can tell from the screenshot, the output format is a little awkward as well, as you have to parse the string to figure out, wether the exponent is negative or not present at all. At least they've could have made the output a fixed length sting by adding a "+" for positive exponents.
Finally, you cannot turn it off completely on the front. According to another post it still draws around 2 Watts when Idle. Maybe depending on the state of the battery. To turning it off completely, you need to access the back side. Or switch the power outlet.
The 10 Megohm range is also rather slow. Measuring the impedance of another multimeter (10 Meg) took a couple of seconds, before settling. 4-Wire Measuring a 100 mOhm 5% resistor compared to a milliohmmeter gave ~3mOhm difference (97 vs. 93 on the 1908). The milliohmmeter itself displayed a difference of 1 mOhm, dependending on wether the testcurrent used was 200mA or 1 A. So to me that is not groundshaking, but not shabby either.
Generally, when measuring resistance (auto), also 4-wire, you need to take ~5 sek into account for it to settle. I do remeber discussions about the ohms speed on the 121gw, so that may be an issue for some. It generally does not do the Kessel Run in less than 12 parsec(tm).
So asides the insulting low max. 1V diode test voltage, that all is nothing, that cannot be dealt with. But again, at least in parts shows unnessecary sloppiness.
I cannot talk about temperature, when I am cold, I get a thicker sweater. That is to say, I do not have any probes. Can utilize PT100 or PT1000. Both 2 and 4 wire.
Capacitance: The only comparisson I have, is my Der EE-5000, itself not a real precicion instrument either. The 1908 has around 50pF fixed uncertainty according to it's manual, but after Null, a capacitor, that is being displayed with 48pF on the EE, with a little variation dependending on the frequency used, is being displayed as 0.04nF on the 1908. That really exceeds my expectations.
A 100nF foil cap is displayed as 92.5nF on both meters, with one digit more on the EE. A 100uF elko is being measured 98.02@100Hz on the EE, the 1908 shows 102uF. That all is AC vs. DC measurement. So I am rather pleased with these results. Again, not groundshaking, but makes for a reliable or rather trustworthy impression.
Now I have never seen one in real life, so just judging by paper, but most of the more esoteric functions are also being delivered by the 121GW for less than half the price.
Shure, you do lose a digit (well, only a little more than half, 50000 vs. 120000), some math functions, external triggering, 4 wire ohms measurement, and probably step down a little on the display, although I am sure it is fine as well, but may gain speed and portability. And gain a proper Diode measurement as well as low current and volt ranges. And at least some form of peak measurement.
Well, and you do lose linux compatibility, but as far as I get it, the interest in this is rather little anyway. To be polite. So, if it was not for this reason, initially I'd probably went for the 121GW. Now however I do enjoy the better usability compared to any handheld meter.
Mine happens to be returned unit, that I got in de facto new condition, but obscenely cheap. Still more than a 121gw, of course.
With its comparably small size, light weight, direct and immediate operation, this outstanding display, with that added flexibility of dual measurements, that seemless and hasslefree PC connectivity it will surely become my goto first device. It just a pleasure to use. Sometimes reality is more than just specs on paper. YMMV, again.
And while I contacted the seller beforehand, this is a definite keeper for me. I am however not sure, wether I would spend the full retail price for it. But know that I actually have used it a little, I am also not sure, if I so did (buying at retail price), wether I still would not want to keep it.
This may hint the dilemma vendors face that still produce in europe, as Hameg devices generally have only mediocre specs as well at an even more premium price. However Hameg seems to somewhat implement its features way more thoughfully and consequently than it has been done here. But it may show, there is a limit to maintain at least a somewhat competitive pricing for europe made hardware. The developement of the software may be a contributing factor.
Long story short: To me the 1908 seems more an everyday kiss style workhorse meter than something fancy or special you'd have to bow before to get your 24th digit and fortune telling. And what you usually associate with a benchtop meter.
Not that I mind those at all! But those would usually not be the thing I'd grab first. That may just be me, and in addition from a purely hobbyist view. Pros will have completely different requirements, no doubt. It does sit somewhere in between a benchtop and a handheld MM and fills a niche.
Oh, and it does feature a pretty comprehensive manual. So those that are scared away by now, it is worth a look.
And again, I only have played with is for a short time, above may contain errors.
And, a final and redundant word about PC connectivity. Since so far nobody really showed any interest in using this with linux, it will not be any different with FreeBSD, but for the history books, the 1908 does work here flawlessly as well:
ugen0.3: <TTI 1908 DMM> at usbus0
umodem0 on uhub0
umodem0: <TTI 1908 DMM, class 2/0, rev 2.00/2.00, addr 2> on usbus0
umodem0: data interface 1, has no CM over data, has no break
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