How often does a multimeter sample AC voltages ? - Page 1
Forum section: electronics / testgear

author: ez24
author_rank: Super Contributor
timestamp: September 08, 2016, 11:42:34 pm
content: HiHow often, times per second, does a multimeter sample AC voltages? I want to find my mains min voltage. I have what I think is called lag voltages and the lag is very fast (blink of an eye). It seems this is one spec I cannot find on any meter. Could it be the LCD refresh rate?Also would the sampling be faster on more expensive meters? Is this something I would have to calculate from the chips used? If so could there be a range of samples?I am not talking about the sample rate that would be recorded to a file. I mean the chances per second that a min value would show up on the meter.thanks

author: bitseeker
author_rank: Super Contributor
timestamp: September 09, 2016, 12:25:19 am
content: Depends on the meter. For example, the HP 34401A can measure AC voltage or current from as slow as 7 sec/reading to as fast as 50 readings/sec. Of course, that still doesn't take into account how short of an anomaly will actually be detected.

author: Faith
author_rank: Unknown
timestamp: September 09, 2016, 12:35:29 am
content: Can your multimeter display peak-to-peak or similar statistics? I usually find that that's quite useful if you want to find out if you're getting irregular voltages (or even PWM) on your source.With that you can just leave your multimeter sitting around for a while and even with a poor sampling rate it's bound to catch any irregularities eventually as long as it doesn't happen too rarely.

author: raptor1956
author_rank: Frequent Contributor
timestamp: September 09, 2016, 12:39:09 am
content: I'm pretty sure than most handheld DMM's will update at least a few times per second and few that I know of vary the update rate in any meaningful way. Bench DMM's, OTH, usually have a button or two that are largely dedicated to changing the DISPLAY update interval though what's happening under the hood maybe another story. That is, when you change the interval to something slower what you're really doing is changing the integration period to average the samples coming in and it's pretty likely that the actual sampling interval is much faster and more or less fixed.So, part of the problem is knowing what the sampling rate is and the other is the integration period.Brian

author: ez24
author_rank: Super Contributor
timestamp: September 09, 2016, 02:26:41 am
content: I started with a Vici VC99 (has a really crappy manual) at 114 v, and two hours later, the min is 106 v. I was looking at the meter when a "blink" happened and the meter did not change.The meter has a 10 min shut off but it has not shut off while reading, this was a pleasant surprise.After the batteries run out, I will try my Owon B35T. I think these are the only meters I have that have a min function.

author: HKJ
author_rank: Super Contributor
timestamp: September 09, 2016, 08:31:58 am
content: Some DMM's can automatic log events on the mains (Like Gossen Energy).It sounds like you interest is not only how fast the meter samples, but how fast/slow the input filter is.

author: ez24
author_rank: Super Contributor
timestamp: September 09, 2016, 08:39:38 am
content: Quote from: HKJ on September 09, 2016, 08:31:58 amToo bad it is out of my price range, I think it costs more than my car is worthhttps://www.amazon.com/Dranetz-Metrawatt-M249AKIT1-Multimeter-Measurement/dp/B00E3Y60TYMy min is now down to 105 v