Where are the Graphing Meters? - Page 1
Forum section: electronics / testgear

author: JayMan07
author_rank: Regular Contributor
timestamp: September 20, 2020, 11:26:53 pm
content: I'm a technician for large generators and many different types of HVAC equipment. I regularly use several different flukes, but every now and then I need a graphing meter for my troubleshooting. Currently, I use a snap on vantage and it has served me well, but it is super old. I'd like to get a nicer meter but cannot find something comparable.The thing I like about the vantage is that it can graph anything like ohms, frequency, and volts AC (so you see a line representing the AC average and not the sine wave...very useful in my line of work). I've seen a few other graphing meters out there but they seem slow, like 2 samples a second.Do you all know of anything out there? Am I just going to be forced to buy a regular portable scope that only graphes voltage? Snap on did make some successors to the vantage but they reduced the VAC capability to 50 volts so that's unfortunate. They are also pretty old, and still twice the price of a good handheld scope.Does something like this have descent multimeter graphing functions?Siglent SHS810https://www.amazon.com/Siglent-SHS810-Oscilloscope-2-Channel-Multimeter/dp/B00GQNNSEK/ref=sr_1_21?dchild=1&keywords=oscilloscope+multimeter&qid=1600644265&sr=8-21Hantek 2 CH DSO1202Bhttps://www.amazon.com/Hantek-DSO1202B-Handheld-Oscilloscope-Multimeter/dp/B00GWL0D1W/ref=sr_1_13?dchild=1&keywords=hantek+oscilloscope+multimeter&qid=1600644097&sr=8-13

author: Someone
author_rank: Super Contributor
timestamp: September 21, 2020, 01:17:27 am
content: Its been a while since I used one but Fluke 287/289 do trend plots at the really slow update rate so you won't see details of waveforms:https://www.eevblog.com/forum/testgear/data-logging-dmm/There has been really impressive feature growth in desktop DMMs, starting to overlap with low end scopes:1MS/shttps://www.tek.com/tektronix-and-keithley-digital-multimeter/dmm650050kS/shttps://www.keysight.com/en/pcx-2832416/truevolt-series-65-75-digit-multimetersMost scopes won't do current/resistance/capacitance measurements directly so sticking with a multimeter makes sense.

author: JayMan07
author_rank: Regular Contributor
timestamp: September 21, 2020, 01:30:37 am
content: Thanks for the reply! Yeah I did hear that some of the desktop dmms can graph especially if you can run the data into a pc but unfortunately I'm limited to portable devices since I have to use them in the feild.

author: Someone
author_rank: Super Contributor
timestamp: September 21, 2020, 02:04:29 am
content: Those are two example desktop DMMs that do really useful graphing without needing a computer connected.You're probably not going to find a battery powered product that does everything you want. Most of the portable scope/multimeter combinations are basically two entirely separate devices inside the same case.With Trend Plot (Measurement Trend, Trend Function) it is possible to do frequency or amplitude plotting from a captured waveform on a scope. But thats usually on higher end products which aren't battery powered (not available on that hantek, but available on fluke scopemeters), and if you want to see waveforms current then you'll need a current probe too (and power for it).

author: JayMan07
author_rank: Regular Contributor
timestamp: September 21, 2020, 02:18:02 am
content: Yeah I was afraid of that. I guess there really may be nothing out there. That's a real shame. With everything available you'd think something as simple as a good graphing meter would be readily available.I've also never understood why scopes can't at least have a math function that would graph AC as a line. AC current and voltage is a million times easier to analyze if you can see it as a line rather than a sine wave. Granted it may be useful to make sure the sine wave is clean but after I know it's a perfect sine wave and 60Hz what I want to see is a graph of the changing TRMS value over time.

author: Someone
author_rank: Super Contributor
timestamp: September 21, 2020, 03:31:23 am
content: The newer Fluke Scopemeters are probably closest to your idea/requirements.There are similar (but less capable) trend functions on R&S and Keysight battery scopes., but they are further away from a multimeter.

author: ivaylo
author_rank: Frequent Contributor
timestamp: September 21, 2020, 05:12:30 am
content: Look for a dmm with bluetooth connectivity and a corresponding app for your mobile OS of choice. Not quite the way you are used to (you need a second device), but the new ways have advantages in some situations (can graph multiple dmms simultaneously, etc). Tell us what you picked...

author: 2N3055
author_rank: Super Contributor
timestamp: September 21, 2020, 06:54:31 am
content: What you are looking for is called a scopemeter.There are many, actually, but they are not very cheap.From Fluke, Keysight to Micsig, Siglent, GW Instek.Some of them have isolated scope channels.http://micsig.com/html/2.htmlhttps://www.gwinstek.com/en-global/products/detail/GDS-300https://www.siglenteu.com/handheld-oscilloscopes/shs1000-series-isolated-handheld-digital-oscilloscopes/https://www.siglenteu.com/handheld-oscilloscopes/shs800-series-handheld-digital-oscilloscopes/They are not inexpensive, but are fully featured scopes and multimeters... Some will even decode serial protocols...

author: 2N3055
author_rank: Super Contributor
timestamp: September 21, 2020, 06:58:49 am
content: Quote from: JayMan07 on September 21, 2020, 02:18:02 amScopes by definition are doing exactly that: showing voltage as a line. Except they are so fast that they show things that are very fast.If you slow down timebase they show voltage trend instead of waveform..Many scopes have additional function of measurement trend: You set up measurement of AC RMS and then switch on trend display of that measurement, and you get exactly what you want. Even cheap Rigol DS1054Z has that function.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 21, 2020, 07:33:38 am
content: there are many Scopemeter option nowadays.. from cheaper brand $60 that resembles DMM shape, to more expensive $200 - $500 closer and closer look as an oscilloscope and input... you can google for review of the best scopemeter available today...$62 Intelligent Oscilloscope Portable Scope Meter Digital Storage Scopemeter Q5A2$200+ UNI-T UT81B

author: JayMan07
author_rank: Regular Contributor
timestamp: September 21, 2020, 11:08:45 am
content: Ok it looks like I need to look deeper into scope meters. Initially it just seemed like they would graph but in a kinda crude way. Those gw instek ones look really nice! I'm sure they're super expensive as well lol.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 21, 2020, 04:42:47 pm
content: The cope meters are about showing the voltage at any moment in time with something like µs (and sometimes better) resolution.A graphing DMM would be more like measure the RMS value over a few periods and than show RMS amplitude over time. In theory with would be possible the an extra math function on a scope, though I have not seen it.There are a few low end scope meters / miniature battery powered scopes. For mains and similar this may be fast enough. However scope meters tend to be not CAT rated very high.For current measurement there are clip on probes as an addition to existing meters and many of them also work with a scope for the lower frequency.

author: bicycleguy
author_rank: Frequent Contributor
timestamp: September 25, 2020, 01:42:55 am
content: Nobody mentioned the 121GW?This along with an iPhone is all you need. It plots whatever is displayed at about 2 per second. If you want to save the run it dumps a list to email or whatever. Using it as a large secondary display is often usefull.Don't remember if there is an android app.

author: J-R
author_rank: Super Contributor
timestamp: September 25, 2020, 06:09:30 am
content: The 121GW has Android and Windows 10 apps. Super easy to graph in real time, but as you mentioned only about 1-2 samples per second.Keysight has a reasonable selection of logging handheld DMMs. A while back I picked up the U1461A which can log up to 40 samples per second. Despite the dot matrix OLED display, it can't graph on the meter.Given that the only connection the U1461A (and similar) has is via IR, I don't see how high-speed real-time logging to an external device would be possible. Typically I've seen a few samples per second maximum. So you would need to log internally for example 10 seconds at 40 samples per second and then download and graph the 400 data points after the fact...