Streetlights now use radio control from a master, using, at least round here, a GSM type of protocol on a dedicated frequency, so every individual light can be set, at different brightness levels. And they do do this - at least on a street basis. And they monitor every light.
I take the 50Hz in, pass it though a three stage RC filter then into the TMR1 input of a PIC 16F628 which has a Schmitt input at thresholds of 30% and 70% of the rails. , ie 1.5 / 3.5V so plenty of hysteresis. Andy www.g4jnt.com On Fri, 12 Feb 2021 at 16:57, Adrian Godwin <[email protected]> wrote: > I wouldn't be surprised to find that streetlight clocks use the same old > Sangamo or Venner electromechanical timers that they've always used, and > are far more of a problem to correct than domestic clocks. > > Andy, what equipment do you use to monitor the cycle count ? > > > On Fri, Feb 12, 2021 at 2:55 PM Lux, Jim <[email protected]> wrote: > > > On 2/12/21 3:12 AM, Andy Talbot wrote: > > > I maintain a real time display of mains frequency, and the cumulative > > > timing offset from real time. It was last reset 10 days ago when we > > had a > > > brief power outage (HV fault a mile or so away). > > > > > > Since then, for the first few days the timing discrepancy kept within > > > plus/minus perhaps 20 seconds. But in the last couple of days is has > > crept > > > up and is now sitting at +48 seconds. On average the frequency will > > have > > > been running about 0.013Hz high to give that. > > > > > > Given Nat. Grid still aim to average out to exactly 50Hz, does anyone > > know > > > if there is a time scale associated with that long-term average? > > > > > > I would think they try to hold it over 1 day, so that mains driven > > clocks don't run slow or fast. That being said, I wonder how many > > clocks are still being built using a synchronous motor drive? Given that > > all the clocks on appliances in my kitchen have drifted apart, I'll bet > > they use their internal microcontroller crystal as a reference. > > > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
