6 ms·
My suspicion is that NTP (and GPS) have generally superseded the synchronous grid for timekeeping. It has for every application that I know of. Simultaneously,
by i_am_proteus 6y ago
My suspicion is that NTP (and GPS) have generally superseded the synchronous grid for timekeeping. It has for every application that I know of.
Simultaneously, I suspect some systems still do rely on grid time.
- nottorp 6y agoComputers (or anything containing a proper computer) don't care about grid frequency for time keeping. On the consumer side, your microwave, coffee machine and even bedside clock will. Not sure on the industrial side.
- read_if_gay_ 6y ago> your microwave, coffee machine and even bedside clock will. I guess a ~0.5% deviation for a couple minutes is going to be tolerable here.
- nottorp 6y agoOh found it. Looks like this went on for more than a couple minutes: https://www.theguardian.com/world/2018/mar/08/european-clocks-lose-six-minutes-dispute-power-electricity-grid https://www.theguardian.com/world/2018/mar/08/european-clock...
- LeonM 6y agoThe grid is never exactly 50Hz, it varies quite significantly. On the long run, the grid operators try to average to 50Hz as close as possible, just so that clocks continue to operate somewhat accurate. In fact, it is even in the FAQ of the article: "The transmission grids of the countries of Continental Europe are electrically tied together to operate synchronously at the frequency of approximately 50 Hz"
- driverdan 6y agoBased on the article the control limits are 49.8 to 50.2 Hz (+-0.2hz). That's less than 1%, not very significant. One of the places I lived in Austin, TX had a range with a clock that used grid frequencies (60hz in the US). It was dead accurate. I only changed it for daylight savings, it never need adjustment.
- klodolph 6y agoThe US used to guarantee 5,184,000 cycles per day. That’s not, like, 1% or anything comparable, that’s zero (with temporary deviations). Any clock which referenced line frequency would be dead accurate over the long-term. There’s a system called Time Error Correction (TEC) which would do this (refer to WEQ-006 and the like). Obviously this error is measured relative to some reference clock. I’m not sure what the current status is, but my understanding is that there are efforts to retire this system and allow the speed to drift more.
- jwr 6y ago> On the consumer side, your microwave, coffee machine and even bedside clock will I'd be very surprised. It's cheaper to build in a 32.768kHz crystal for timekeeping than try to access the grid frequency from the isolated low-voltage circuit.
- alkonaut 6y agoI have a microwave and oven from the same brand, and their digital clocks diverge about 2minutes in 24h. I just don't understand how it's possible to build a device that poorly in 2020 (they are new) and I also wonder which tech they use for timekeeping. Is it possible that one of them uses a crystal and the other uses the 50Hz? That would explain a small difference.
- eqvinox 6y agoIt's easy enough to mistune a 32768Hz clock crystal by shitty electronics engineering, unfortunately :/ 50Hz might have temporary variations, but it's controlled so that over a longer period of time, you always get the correct number of cycles, e.g. 180000 in an hour. This also means that going off the 50Hz power grid theoretically has better (or even perfect) long-term accuracy. Also means that if you adjusted your clock for this separation event, you'll have to adjust it back :D
- thaumasiotes 6y ago> I have a microwave and oven from the same brand, and their digital clocks diverge about 2minutes in 24h. That's much, much worse than a cheap digital watch from 20 years ago.
- labawi 6y agoI was under the impression semaphores use grid power as a clock source. And the case of missing payer in southern Balkan got the timing shifted by a few minutes.