8 ms·

How does this affect timekeeping? Normally, if there is a drop in grid frequency, a small increase will be planned later to maintain a long term average frequen

by tyho 6y ago

How does this affect timekeeping? Normally, if there is a drop in grid frequency, a small increase will be planned later to maintain a long term average frequency of 50Hz so that clocks that keep time by grid frequency stay accurate [0]. The network split seems to have made this impossible, during the split, the cycle counts for the two regions diverged, and the split ended before this was reconciled. Will people in one of the regions have to adjust their clocks? [0]: https://en.wikipedia.org/wiki/Wide_area_synchronous_grid#Timekeeping https://en.wikipedia.org/wiki/Wide_area_synchronous_grid#Tim...

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My suspicion is that NTP (and GPS) have generally superseded the synchronous grid for timekeeping.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 ago
  Computers (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 ago
      Oh 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 ago
      The 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 ago
        Based 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 ago
        The 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 ago
      I 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 ago
        It'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.
        alkonaut 6y ago
        I know. It's worse than the pendulum clock I have to crank at my grandma's once a week! Progress!
        andai 6y ago
        Much worse than a digital watch from the 80s. (Maybe 70s?)
- labawi 6y ago
  I 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.
izacus 6y ago
Clocks on our ovens and some microwaves got out of sync during that period. I haven't seen any other device rely on the network frequency for timekeeping - everything time sensitive is already on NTP and GPS time.
- tzs 6y ago
  OT: Several commenters have mentioned both their oven clocks and microwave clocks getting out of sync. I'm curious as to why people set both of these clocks in the first place. The microwaves and ovens I've seen do not actually require you to set the clock. None of their cooking features and functionality depends on it. It's just a convenience feature. I doubt that most people actually need two clocks in the kitchen, so why not just set one of them (or neither if you don't need a kitchen clock at all)?
  - Denvercoder9 6y ago
    Lots of ovens and microwaves don't allow you to disable the clock, so the alternative to setting them is to have them run out-of-sync, which is much more irritating than having to set them.
    - tzs 6y ago
      Ah...I'd forgotten about the ones that always show the time regardless of whether or not it has been set. I can see how that would get annoying. I guess I've been lucky in that all the microwaves I've had over the last couple of decades, and the ones we had at work, do not show the time unless you've set it. My current one, which has 7 segment LEDs for the time digits, blanks all the digits, leaving just the colons. My prior one showed "--:--" if time was not set. The one before that had a graphical display and just showed blank where the time would normally go.
    - mrmanner 6y ago
      Mine has two alternatives: Clock or blinking red light. I choose the clock...
  - BrandoElFollito 6y ago
brummm 6y ago
In Europe, many countries have radio signals that many clocks use to sync their time that is based on some atomic clocks. For example, in Germany these are called Funkuhr and the signal comes from an atomic clock in Braunschweig if I'm not mistaken.
- ficklepickle 6y ago
  We have this in North America as well. The station is called WWVB. https://www.nist.gov/time-distribution/radio-station-wwvb https://www.nist.gov/time-distribution/radio-station-wwvb

by tyho 6y ago

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 ago
Computers (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 ago
    Oh 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 ago
    The 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 ago
      Based 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 ago
        The 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 ago
    I 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 ago
      It'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.
      - alkonaut 6y ago
        I know. It's worse than the pendulum clock I have to crank at my grandma's once a week! Progress!
      - andai 6y ago
        Much worse than a digital watch from the 80s. (Maybe 70s?)
labawi 6y ago
I 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.

izacus 6y ago

Clocks on our ovens and some microwaves got out of sync during that period. I haven't seen any other device rely on the network frequency for timekeeping - everything time sensitive is already on NTP and GPS time.

tzs 6y ago
OT: Several commenters have mentioned both their oven clocks and microwave clocks getting out of sync. I'm curious as to why people set both of these clocks in the first place. The microwaves and ovens I've seen do not actually require you to set the clock. None of their cooking features and functionality depends on it. It's just a convenience feature. I doubt that most people actually need two clocks in the kitchen, so why not just set one of them (or neither if you don't need a kitchen clock at all)?
- Denvercoder9 6y ago
  Lots of ovens and microwaves don't allow you to disable the clock, so the alternative to setting them is to have them run out-of-sync, which is much more irritating than having to set them.
  - tzs 6y ago
    Ah...I'd forgotten about the ones that always show the time regardless of whether or not it has been set. I can see how that would get annoying. I guess I've been lucky in that all the microwaves I've had over the last couple of decades, and the ones we had at work, do not show the time unless you've set it. My current one, which has 7 segment LEDs for the time digits, blanks all the digits, leaving just the colons. My prior one showed "--:--" if time was not set. The one before that had a graphical display and just showed blank where the time would normally go.
  - mrmanner 6y ago
    Mine has two alternatives: Clock or blinking red light. I choose the clock...
- BrandoElFollito 6y ago

brummm 6y ago

In Europe, many countries have radio signals that many clocks use to sync their time that is based on some atomic clocks. For example, in Germany these are called Funkuhr and the signal comes from an atomic clock in Braunschweig if I'm not mistaken.

ficklepickle 6y ago
We have this in North America as well. The station is called WWVB. https://www.nist.gov/time-distribution/radio-station-wwvb https://www.nist.gov/time-distribution/radio-station-wwvb