Review of Hameg Power Meter - Page 1
Forum section: electronics / testgear

author: DaveW
author_rank: Frequent Contributor
timestamp: February 23, 2013, 11:15:48 pm
content: I just filmed a review of a Hameg power meter after getting frustrated with using a GW Instek unitQuick précis,ProsIt's an really nice unit with a great frequency responseAll readings are very accurateGood softwareConsIt's a really deep bit of test equipment that is mostly emptyIf there are any questions, we'd love to hear them. We've got a teardown coming up as well

author: firewalker
author_rank: Super Contributor
timestamp: February 24, 2013, 09:31:00 am
content: Nice! I am fan of Hameg equipment (maybe because as a student our lab was equipped with Hagen instruments). I think that many Hameg instruments are ~40 cm in length in order to pile them up.Alexander.

author: qno
author_rank: Frequent Contributor
timestamp: February 24, 2013, 09:34:34 am
content: Th Airbus A380 uses 380 to 800 Hz AC power.

author: firewalker
author_rank: Super Contributor
timestamp: February 24, 2013, 11:05:24 am
content: Could you just connect it to a pc and fire up a terminal to the specified com port and watch if there is any data? Use something likehterm. Also could you post the usb VID/PID?Alexander.

author: Unknown
author_rank: Unknown
timestamp: February 24, 2013, 12:23:18 pm
content: hi,Once you get the the power displayed on the oscilloscope how you can measure it? You get W/div instead V/div?

author: HKJ
author_rank: Super Contributor
timestamp: February 24, 2013, 12:53:49 pm
content: Interesting to see this review, but I am missing a few functions in it:Lower current range, with a 1mA resolution it cannot really measure standby power below 1W.Why does the logging function not have more columns and logs all the different measurements at the same time.

author: firewalker
author_rank: Super Contributor
timestamp: February 24, 2013, 01:09:23 pm
content: Quote from: HKJ on February 24, 2013, 12:53:49 pmI am guessing that the instrument needs at least one second to complete and send a measurement. To complete another type of measurement it needs to change something and send the new data.As I can understand the software first sends a command to change the measurement type and then the meters sends the data. It isn't like it always measures everything and just displays a portion of that. Maybe if the interval between logging is big enough it could send the data all together.Alexander.

author: HKJ
author_rank: Super Contributor
timestamp: February 24, 2013, 01:30:01 pm
content: QuoteLooking at the software protocol it looks like this is the case.QuoteMy guess is that it does measure everything at once (The values are very closely related), but maybe it only read one of the registers in the measurement chip at a time.

author: DaveW
author_rank: Frequent Contributor
timestamp: February 24, 2013, 01:39:59 pm
content: Quote from: qno on February 24, 2013, 09:34:34 amThat's a wide range of frequencies, glad I don't have to design with that. Any idea why, just out of curiosity?Quote from: firewalker on February 24, 2013, 11:05:24 amI'll try that, I suspect it's an interrogation style command/response style, but the software does have a "show command" option, so I'll upload this data if nothing comes up on the serial terminal

author: DaveW
author_rank: Frequent Contributor
timestamp: February 24, 2013, 01:44:25 pm
content: Quote from: Oracle on February 24, 2013, 12:23:18 pmThe voltage is based on the percentage of the full scale deflection of the current range, I presume to cover the very wide range of power efficiently. If you take the device out of autoranging mode, then you can definitely apply a simple scaling factor to get the reading in Watts. We did have an National instruments datalogger doing just this to measure the power quicker than the 1 hertz pc based logging. Downside was that early in the startup process the readings weren't particularly accurate as the range had to be fairly high to accommodate the running power of the switchmode

author: DaveW
author_rank: Frequent Contributor
timestamp: February 24, 2013, 01:58:30 pm
content: Quote from: HKJ on February 24, 2013, 12:53:49 pmYeah, with only a 1mA resolution it won't work too well for the ultra low power devices, for most of the modern low power circuits I'd probably be looking at a source measure unit for those measurements.I'd love to know why it won't do all the readings in one go; Looking through the commands it talks about different modes so it might only calculate one parameter per measurement. Might be possible to update more frequently than 1 hertz though

author: saturation
author_rank: Super Contributor
timestamp: February 24, 2013, 02:44:06 pm
content: I think you make a good case for the Hameg for frequencies above Instek's spec sheet of 400 Hz. It was good you could get both to read far above their rated specs. Also, the Instek is no longer sold, so in this price range, there aren't too many options, and the Hameg and Instek have similar list prices.Datasheets for the Hameg say its rated to 1kHz, so its fine for most power readings used commercially.

author: Circuitous
author_rank: Unknown
timestamp: February 24, 2013, 02:47:48 pm
content: DaveW, Great review! I'm putting one of those on my birthday list.Any chance of a teardown?

author: DaveW
author_rank: Frequent Contributor
timestamp: February 24, 2013, 03:21:27 pm
content: Quote from: Circuitous on February 24, 2013, 02:47:48 pmWe've done a teardown as well, I was going to upload it but got distracted by packing for Embedded World. I'll start uploading it now!

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: February 24, 2013, 04:46:19 pm
content: Quote from: DaveW on February 24, 2013, 01:39:59 pmOlder aircraft use 115V 400Hz for AC power which requires a constant speed drive for their generators, which add weight and complexity. The A380 and the Boeing 787 both use variable speed generators which don't need constant speed drives, but it also means the output can vary between 380Hz and 800Hz depending on engine speed. But most of the time (enroute) the output is relatively stable (IIRC somewhere around 500-600Hz), the variations mostly come during take-off (where the frequency goes up to 800Hz because the engines are running in max dry) and approach/landing (below 500Hz as the engines are mostly at or a bit above idle speed).This of course increases the effort required to adapt electric consumers to be able to deal with the variation in frequency, however it does away with the constant speed transmission which is a major point of failure.

author: DaveW
author_rank: Frequent Contributor
timestamp: February 24, 2013, 05:15:16 pm
content: Quote from: Circuitous on February 24, 2013, 02:47:48 pmHere you go!

author: DaveW
author_rank: Frequent Contributor
timestamp: February 24, 2013, 05:23:31 pm
content: Quote from: Wuerstchenhund on February 24, 2013, 04:46:19 pmInteresting, I work on military aircraft and haven't seen that come through on any yet; maybe it's just a little behind at the moment. Thanks for the answer-I've learnt something new today!

author: firewalker
author_rank: Super Contributor
timestamp: February 24, 2013, 08:24:24 pm
content: It uses an FT245BL chip, so it will be recognized by Linux. And if they show the command a python script will be trivial toy control and read this instrument.Alexander.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: February 24, 2013, 10:42:23 pm
content: Quote from: DaveW on February 24, 2013, 05:23:31 pmWell, it's coming in military aviation, too. The JSF (F-35) for example has a variable speed generator as well (with 270V instead of the common 115V).

author: saturation
author_rank: Super Contributor
timestamp: February 25, 2013, 05:48:48 pm
content: Nice teardown very little that can go wrong, shame its so long, not a biggie but a lot of unneeded space and modern instruments aren't in that size these days. If I were to stack a short instrument with longer ones I can easily add a rear support, but I cannot shorten the chassis easily; I don't think this Hameg has much competition for these types of power meters; power analyzers or Yokogawa's 310 are >3x as much.Quote from: DaveW on February 24, 2013, 03:21:27 pm

author: HKJ
author_rank: Super Contributor
timestamp: February 25, 2013, 06:30:56 pm
content: QuoteThere is the Metrahit Energy, it is a handheld meter. It can do better than this meter, but is also more expensive.Sadly Dave did never review it, probably because he lost the calibration during a software update.

author: olsenn
author_rank: Frequent Contributor
timestamp: February 25, 2013, 07:32:44 pm
content: Can someone explain to me what the difference is between a power meter and a programmable multimeter that can read/display voltage and current at the same time and automatically display watts if you're too lazy to multiply? Is it just for devices that use more than the 10A fuse in the DMM can handle?

author: HKJ
author_rank: Super Contributor
timestamp: February 25, 2013, 07:36:39 pm
content: QuoteThe difference shows up when the power factor <> 1. A meter that only measured volt and ampere will not compensate for this, only a power meter will.Remember that the formula for AC power is: power = voltage * current * power_factor

author: saturation
author_rank: Super Contributor
timestamp: February 25, 2013, 09:53:31 pm
content: Yes, quite an impressive power meter rated to 100kHz, but I think its more like the Yokogawa class,and at > 4x the price, ~ $3500 US vs $815 for the Hameg, you get a lot too for it being portable compared to most power meters being benchtop units.At that price also, it competes with power analyzers which offer built in scopes like the Fluke 43B.Quote from: HKJ on February 25, 2013, 06:30:56 pm

author: HKJ
author_rank: Super Contributor
timestamp: February 25, 2013, 10:05:39 pm
content: QuoteI do not know where you got that price from, at Conrad it is about €1000 or $1300 and that includes German VAT. It is more expensive than the Hameg, but only about 50%.Computer interface and external power supply is rather expensive, but it will not be anywhere near $3500.

author: saturation
author_rank: Super Contributor
timestamp: February 26, 2013, 12:50:27 pm
content: My error, you are right HKJ. I've corrected my post. For 2x the price, then, the Gossen offers quite a bit of capability.Quote from: HKJ on February 25, 2013, 10:05:39 pm