Can't find a fast Logging Ammeter  - Page 1
Forum section: electronics / testgear

author: maxwellVII
author_rank: Newbie
timestamp: August 02, 2017, 11:48:29 pm
content: Hello, I've been trying to find a standalone meter that can log current readings to a file at around 10000hz, that isn't a few thousand dollar industrial device. I haven't had much luck so far, the closest match I could find was the Fluke 287 which claimed in it's data sheet to be able to capture transients up to 250us, which isn't quite fast enough.The rate at which logging meters can log seems to be documented very infrequently, does anyone here have any experience with meters which can log in the 10000hz range?

author: IanB
author_rank: Super Contributor
timestamp: August 02, 2017, 11:58:27 pm
content: Most hand held multimeters can only log at a few times per second.Do I understand you want to record about 10,000 readings per second?If so, you will need to look to benchtop meters, oscilloscopes, or dedicated logging solutions based on microprocessors. Such solutions either will be costly, or will involve significant custom build effort.

author: macboy
author_rank: Super Contributor
timestamp: August 03, 2017, 02:04:20 am
content: What current range? 1 mA? 1000 A?What precision? Accuracy?My first thought is a high end bench DMM connected to PC for data capture, using an external shunt. Not many can do 10 kS/s but the 3458A for one can go up to 100 kS/s.

author: maxwellVII
author_rank: Newbie
timestamp: August 03, 2017, 05:32:59 am
content: Looking for something that can do max 3A with 1ma resolution, but those seem to be the easy requirements to meet.I was thinking the best non-off-the-shelf solution would be a current-to-voltage converter (probably hall sensor based, avoid the resistance of a current shunt), and a cheap digital oscilloscope, but again, would prefer an off-the-shelf solution.

author: ivaylo
author_rank: Frequent Contributor
timestamp: August 03, 2017, 07:21:04 am
content: How many readings (or how long time) do you want it to be able to store?

author: HighVoltage
author_rank: Super Contributor
timestamp: August 03, 2017, 08:57:47 am
content: The Agilent34410Ashould work for you.It does 10.000 readings / sec at 5½ digits.It also does your range requirements of DC 100 µA to DC 3 A / at a resolution of 0,0001 µAYou can find them for around $ 500, if you are lucky.

author: alm
author_rank: Super Contributor
timestamp: August 03, 2017, 09:07:24 am
content: An 8-bit scope will not give you 3 A with 1 mA resolution. That would need at least 13 bits. You could consider one of the niche high-resolution scopes (e.g. Picotech). 10 kS/s is very fast for a bench meter, only a few high-end or recent meters will be able to do that. Most top out at a few hundred or thousand S/s. Never mind the transfer speed.If you use a Hall sensor, do not forget the bandwidth of the Hall sensor. Some are only a few kHz, which might be too low for you.

author: LaurentR
author_rank: Frequent Contributor
timestamp: August 03, 2017, 09:25:12 am
content: Quote from: HighVoltage on August 03, 2017, 08:57:47 amAlternatively, the newer 34465A with the right options can do 50k samples/s and has a memory of 2M samples.

author: Fungus
author_rank: Super Contributor
timestamp: August 03, 2017, 10:49:06 am
content: Quote from: maxwellVII on August 02, 2017, 11:48:29 pmGet a current shunt and use a fast logging voltmeter...?

author: MrW0lf
author_rank: Frequent Contributor
timestamp: August 03, 2017, 11:37:14 am
content: Some notes about Picotech stuff... Off the shelf there are several high-bit ones but most interesting IMHO is this differential 14-bit scope:https://www.picotech.com/oscilloscope/4444/picoscope-4444-overviewCan be supplied with current probes.However must be aware of current software limitations - PS6 software cannot do unlimited capture:QuoteIf want unlimited must use SDK.Then there are some cheaper 4000-series high bit ones and quite cheap 16-channel, 12-bit datalogger:https://www.picotech.com/data-logger/picolog-1000-series/multi-channel-daqIt will max out @100kSa/s shared bw, but also only with SDK according to spec. Also needs some external current-sensing contraption.Then there are my doings:https://www.eevblog.com/forum/testgear/what-you-do-with-math-channels-on-oscilloscope/msg1130997/#msg1130997Using some Arduino based current-measurement contraption can "tunnel" up to 16bit analog value thru MSO digital channels, and use as extra high-bit analog channel on some cheap Pico MSO (I did on old 2205 MSO costing nothing nowdays). But point of this is gaining all the software analysis like on regular channel. If goal is just datalogging probably can do it on Arduino Due etc fast board directly.Overall... since task is actually very simple it would make sense to use SDK. Just writing to file is couple lines of code I guess... I do not own 4444 or 1216 so cannot check. If any further interest heres their support forum:https://www.picotech.com/support/

author: joeqsmith
author_rank: Super Contributor
timestamp: August 04, 2017, 02:08:56 am
content: Quote from: maxwellVII on August 03, 2017, 05:32:59 amEasy enough to do with LabVIEW and some of the NI products but the cost constraint would be a problem... On the cheap side, I would just buy an OTS DAQ, what ever sensor fits your needs and run the student version of LabVIEW.

author: onlooker
author_rank: Frequent Contributor
timestamp: August 04, 2017, 02:37:23 am
content: Did anyone mention audio card? Software is free.

author: joeqsmith
author_rank: Super Contributor
timestamp: August 04, 2017, 03:15:46 am
content: Quote from: onlooker on August 04, 2017, 02:37:23 amAny specific one you have in mind? I assume OP would want DC. It also may need to be isolated. Hard to say what OP had in mind. Not much to go on.

author: onlooker
author_rank: Frequent Contributor
timestamp: August 04, 2017, 03:34:28 am
content: No. Just a thought. But as you said, ac coupling may be a problem.

author: kalel
author_rank: Frequent Contributor
timestamp: August 04, 2017, 04:04:20 am
content: Quote from: joeqsmith on August 04, 2017, 03:15:46 amThis is a nice software:https://www.zeitnitz.eu/scope_enBut, I never had the hardware to use it. Hardware being I presume a USB sound card with custom input protection circuit, some op amps to solve impedance issues and some input jacks and probes. Not exactly a simple feat for me (and I'm not sure if the results are worth it), although many people here will have the ability.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: August 04, 2017, 07:16:45 am
content: Quote from: joeqsmith on August 04, 2017, 02:08:56 amhttps://github.com/picotech/picosdk-ni-labview-examplesHave not tried these however, like "real programming" better...