Review - Gossen Metrawatt Metrahit Energy - Page 1
Forum section: electronics / general

author: jahonen
author_rank: Super Contributor
timestamp: October 06, 2010, 05:01:25 pm
content: So I finally decided to write something I observed about this thing. I originally intended to get a bench DMM to accompany my Fluke 89IV, but I came across this one. Now that Dave has one coming for him to review, I'll write some observations/features worth of mentioning here, so we'll see if we get similar experiences.Price point was quite similar for (better accuracy) benchtop multimeter (like Agilent 34401A), but because this thing has power measurement function and also AC-power adapter (for those moments when battery runs out or I need to perform longish logging task) and I don't necessarily need the extreme accuracy, I decided to go with Metrahit Energy. I got the power measurement adapter PMA16, IR cable and AC adapter at same time.Battery life is specified as 120 hours, and the meter uses two AA batteries. Environment IP-rating is IP52. Meter comes with DKD calibration certificate along with test results/limits. For safety-concerned people, the meter is CAT III rated up to 600 volts, and CAT IV rated up to 300 volts. AC adapter naturally has similar CAT rating. Current range is protected by 10 A fuse, specified breaking capacity is 30 kA @ 1000 VAC/DC. And naturally, AC measurements are true RMS, with bandwidth of 100 kHz.Meter has datalogging capabilities (memory size is 16 Mbits), and meter can be commanded via IR adapter COM cable by using serial terminal program. Of course, Gossen has their own MetraWin software for DMM computer interfacing. The logging has adjustable time interval from 0.5 ms up to 9 hours.Display has 60000 counts (4 6/7 digits). Here are some accuracy figures, you can find more detailed specifications inGossen Metrawatt pages:DC volts 0.02%AC volts 0.2% (AC) 1% (AC+DC)DC amps 0.05-0.2%AC amps 0.5% (AC) 1% (AC+DC)Ohms 0.1-0.5%Apart from usual volts, ohms and amps measurements, this thing also has power quality (harmonics, dip, swell, peaks etc. of mains AC voltage), frequency (up to 1 MHz), Temperature using thermocouple and RTD's, diode test, power and energy, cable length measurement and conductivity measurement functions.Autorange seems to exhibit same sort of "first reading overshoot" than Dave noticed in Metrahit X-tra review, otherwise, it works great.AC voltage harmonics measurement does not work with arbitrary frequency, but needs to be 16.7, 50, 60 or 400 Hz.Continuity test reaction time is I think good enough. Not necessary with "Dave"-test method but enough or me anyway. Anyway, it is specified by Gossen as less than 50 ms.Temperature measurement is possible not only with usual K-type thermocouples, but with Pt-100/Pt-1000 RTD's too. When using RTD's as sensors, you can numerically or by shorting the leads appropriately set the lead excess resistance for compensation of wire resistance error to temperature reading. Nice feature. No temperature probe included, so get one you like and need separatelyCable length measurement function is interesting, it measures the capacitance and it then calculates the length using constant for particular cable. You must enter the constant manually before making the measurement.Diode test open circuit voltage is 6 volts, so one can test power leds easily.The most interesting function of this meter is definitely the power measurement function. Power measurement function uses all three banana input jacks simultaneously, so you can make a short circuit if you are not careful. But at least for PMA16 adapter, the leads are very clearly color-coded. For AC loads, true, apparent, and reactive powers are shown, and also corresponding energies. When the meter shows apparent power, it also shows a power factor figure (between -1 and 1). Strange thing is that it seems to prefer -1 as perfectly resistive load. Manual states that it is either +1 or -1 for pure resistance.Non-linear AC-loads are also handled correctly (not so obvious thing with cheap power meters). That is important with most switch mode power supplies or anything else with just diode bridge and capacitors, like most conventional audio amplifiers. In addtion to the AC power, but it also does DC-loads. The smallest DC-power I tried to measure was 1 M? resistor fed from 3.3 volts DC, and as you can see, it correctly shows the power, about 11 µW. The power measurement function seems to need around 1 µA before it shows anything, but after that, it goes with 0.1 µA resolution.The probes that came with this thing are something I would call "electrician grade", relatively dull-pointed, but of course otherwise perfectly good ones. Don't try to measure from 0.5 mm pitch SMD's with these things.Sorry for convoluted text, but hopefully you get something out of this "stream of conscience". Hopefully the images tell more than 1000 words. I intended to open this thing but it seemed somewhat reluctant to open, so I'll leave that part for Dave. I guess that there are no big surprises inside considering the manufacturer and price.Regards,Janne

author: Unknown
author_rank: Unknown
timestamp: October 06, 2010, 07:44:10 pm
content: Thanks for the review, seems like a neat bit of kit, although I won't be buying it anytime soon (if ever). I remember seeing a (relatively) cheap DMM with the V/I/power feature in catalogs years ago, so it's probably not a new idea, but it looks well executed (as you would expect from Gossen).

author: PetrosA
author_rank: Frequent Contributor
timestamp: October 07, 2010, 03:20:11 am
content: Anytime I see a Gossen here I get all dreamy eyedThanks for the pics!

author: EEVblog
author_rank: Unknown
timestamp: October 07, 2010, 03:43:15 am
content: It just landed on my desk!It is quite possibly the sexiest meter I've ever used. Frigging brilliant.10pWh resolution!It uses one of these:http://www.cirrus.com/en/products/cs5463.htmlI found a (albeit nicely tacked) bodge resistor inside - my illusion of German manufacturing perfection is shattered!Dave.

author: PetrosA
author_rank: Frequent Contributor
timestamp: October 07, 2010, 03:48:27 am
content: Dave, I am CONSUMED by jealouslyHow long are we going to have to wait for some video of it? Any chance of a teardown before you fly out?

author: Richard W.
author_rank: Regular Contributor
timestamp: August 30, 2011, 05:49:49 pm
content: @jahonen: Could you please take a photo of the AC adapter? Especially the sticker with the technical data would be of great interest.Thanks

author: jahonen
author_rank: Super Contributor
timestamp: August 30, 2011, 06:51:17 pm
content: Quote from: Richard W. on August 30, 2011, 05:49:49 pmSure,I had this one already, tell me if you want better one, DOF is a bit narrow. However, I guess that all relevant texts are just readable, though.Regards,Janne

author: thilo
author_rank: Regular Contributor
timestamp: August 30, 2011, 08:56:24 pm
content: Nice review! Did you ever open it to see if it got the resistor hack too?

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: August 30, 2011, 09:08:03 pm
content: Well If I managed to read the 5V 1000mA with out my glasses on, every one will read it too.Interesting presentation Janne, thanks ( even with some time delay) .

author: bilko
author_rank: Frequent Contributor
timestamp: August 30, 2011, 11:46:07 pm
content: Interesting that the PSU is IP68, can you really operate it under water ?

author: jahonen
author_rank: Super Contributor
timestamp: August 31, 2011, 08:22:19 am
content: Quote from: thilo on August 30, 2011, 08:56:24 pmYes I did, and yes, it also has the resistor like the Dave's one too. I certainly won't lose my sleep because of it, fixes like that are quite normal in first production runs.Quote from: yachtronics on August 30, 2011, 11:46:07 pmThe power supply seems to be potted (at least it feels like it is) so it probably is watertight, but of course finding an usable AC socket there is a different thingRegards,Janne

author: Richard W.
author_rank: Regular Contributor
timestamp: August 31, 2011, 08:45:42 am
content: tusen takkkiitos janneObviously the PSU is a very special construction...IP68 potted and equipped with the thickest 5V DC cable ever. (necessary for the CAT IV 600V)I hoped to see a bought-in part from another german manufacturer(which would be cheaper as 93€ for the Gossen branded psu)Edit:now in the correct language