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| Easy way to test the calibration of a DMM (Fluke 45)? |
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| tggzzz:
--- Quote from: shabaz on April 04, 2024, 02:18:14 pm ---I might try multi-level quoting in the future, to see if it is helps. Others (like me) may well prefer not to see repeated walls of text nested. You can't please everyone. --- End quote --- True, but good taste goes a long way. The same is true in creating electronic hardware and software. --- Quote ---It's up to the reader if they wish to read previous comments or to step in part-way. --- End quote --- Not entirely. Your position assumes that readers are devoting attention to your sub-thread, and are prepared to spend more their time than is necessary. Both represent bad taste. It is polite and considerate to consider the readers. That's the opposite of most yootoob videos, which mainly consider how easy it is for the creator. Waste of my remaining life. |
| shabaz:
(No quoting because I'm responding to the immediate message above): I can't argue with that. I love learning from elegant designs, and hate seeing poor-quality circuits (or badly drawn schematics) or code, although sometimes one can learn a little from that too. I am as considerate to readers as the next man and always try to speak in plain language, annotate, take photos, provide diagrams, or do whatever it takes to help the average reader. I am always genuinely happy to help clarify things because some comment style choices will please some readers and not others. But no one likes it when people try to put words in their mouths that they didn't state, e.g. strawman arguments etc. Sometimes, that's accidental, of course. Same with YouTube videos; you can't please everyone, although there some additional compromises are needed from both creators and viewers because of the extraordinary length of time, learning curve, and skill set it could take for individuals. I believe I have just as negative an opinion about most YouTube content as you might, because I don't like the fact that the viewers are just a means to an end, advert delivery, have to sit through a lot for little information, and so on, for the majority of the content out there. Sometimes people want to see how things are done as if they were peering at a circuit or screen as if they were sitting next to a colleague, but it stinks for the remainder 95% of the time. |
| mawyatt:
--- Quote from: shapirus on April 04, 2024, 10:08:32 am --- --- Quote from: mawyatt on April 04, 2024, 02:39:18 am ---You could see the Grid "Speed Up" at night/early morning and the "Dip" mid day when viewing the instruments chart recorder output over a 24 hours period. --- End quote --- You have just boosted my motivation to finally implement visualization for the frequency data that I'm already collecting with my homemade mains voltage data logger. I plot voltage (which btw is not even remotely suitable to check the accuracy of any voltmeter), but not frequency, yet. --- End quote --- The technique we used way back in ~1970 was for measuring and plotting Frequency Deviation from ideal Mains (60Hz). This involved starting with an isolation step down transformer, followed by passive and active BPF to remove noise, then zero crossing. This squared up signal was used in a low noise PLL that multiplied the Reference (60Hz) by 1000, so the output was now 60KHz, or 1000*Fmains. An NBS traceable OCXO was divided down to 60KHz and the two signals were phase compared. The phase pulses were integrated and sampled on each cycle at 60KHz. This integrated & sampled phase signal was then filtered by two cascaded high order Elliptic LPFs with the 1st null located at 60KHz to remove the residual 60KHz. The signal then was precisely differentiated to yield the frequency deviation, as deltaF = K*dP/dt, where K is the Differential Scaling and Amplification/Attenuation as applied for range settings for display and chart plotting. Very effective instrument at the time. Anyway, hope this helps understand what we did way back then in measuring Mains Frequency Deviation. Best, |
| bdunham7:
The Fluke 45 arrived today and I had a bit of time between tasks to set it up atop the wreckage on my bench and take some initial readings. It didn't get a full warmup, but that's probably not an issue. Here's the numbers, read 'em and weep! As posted elsewhere, my 5220A current amp has gone up in flames for the moment. When it arises from the ashes, or at least I manage to get it off my bench, I'll get back to this meter. |
| J-R:
I think grid voltage is typically going to be highly variable these days since there is so much interconnectivity and buying/selling. My grid-tied inverter claims to use frequency to control import/export and I wonder if that is used on the grid as well. I don't have a way currently to track frequency, but here is a voltage graph for the last year: |
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