Hi all,
Responding to a few comments:
- The DC-DC converter has the same pinout as a 7805. It would be possible
to substitute the linear regulator (as long as you handle the power
dissipation of course).
- I will likely switch to I2C for the LCD on the next revision.
- Adding an input for an
Amusing story:
Back in high school, Ewa Beach Hawaii, I used to notice that the second hand
on the clocks would sometimes slow significantly. This turned out to be caused
by the man who would later become my father in law.
He ran the steel mill, melting old cars into rebar, which was
t...@electrictime.com said:
> In the suburb of Boston where we are located - you never have to correct an
> electrical clock between the daylight saving time changes. This of course
> assumes you haven't lost power - due to major snow storms etc
I agree with the spirit of your comment, but
Line frequency in the USA is actually very accurate over the long term - not
with respect to atomic clocks - but the power companies do correct the line
frequency.
In the suburb of Boston where we are located - you never have to correct an
electrical clock between the daylight saving time
I would recommend dumping that DC-DC converter and going with a simple
3-terminal regulator (or at least adding an option for it). It seems it would
be a lot cheaper and easier for people to source the parts for it.
Dan,
Nice.
Ideas for the next go around
+ Add a 10 MHz in circuit to replace or override the TCXO. , this is
Time-Nuts you know :-)
+ The SPI could be used as the 2nd I/O port
And if one wants to play more the this part or other pics search on
Google for "Curiosity Board by Microchip"
-pete
Hi all,
A few months ago someone on the list made mention of the PIC 16F1619,
prompting me to order a few to check out. It's an interesting little chip
with some nice peripherals. I decided to do a mains frequency monitor
project using it. The project is not quite complete, but you can read about
Hal:
Here's a url for the task-force report:
http://energy.gov/oe/downloads/us-canada-power-system-outage-task-force-final-report-implementation-task-force
I live near Pittsburgh, PA. I think there is ZERO interconnection
between PJM (grid operator we're on) and yours (forgot the name).
[Context is maybe(?) withdrawing the proposal to stop keeping time on the US
power line.]
wb4...@wb4gcs.org said:
Since then, large amounts of generation (primarily coal) has been shut
down, so I was not at all surprised by the request.
I missed the announcement that the request was
Tom,
On 18/11/13 23:15, Tom Van Baak wrote:
Magnus,
I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to
see the results of the professional I-Q demodulated gear that you mentioned.
Can you post raw data, or a sample plot?
I don't have much of that myself. I do
2014 16:39:50 +0100
From: mag...@rubidium.dyndns.org
To: time-nuts@febo.com
Subject: Re: [time-nuts] Mains frequency
Tom,
On 18/11/13 23:15, Tom Van Baak wrote:
Magnus,
I'm going to push back a bit on your mains sampling claim. Mostly, I'd like
to see the results of the professional
Hi Tom,
On 12/03/14 18:15, Tom Knox wrote:
So we know there are deviations in line freq. But it seems strange in
this era of very accurate and inexpensive freq references.
May seem strange, yes.
How much is related to the generation? It seems in this era of
switching supplies and other
To: time-nuts@febo.com
Subject: Re: [time-nuts] Mains frequency
Tom,
On 18/11/13 23:15, Tom Van Baak wrote:
Magnus,
I'm going to push back a bit on your mains sampling claim. Mostly, I'd
like to see the results of the professional I-Q demodulated gear that you
mentioned. Can you post
So we know there are deviations in line freq. But it seems strange in this
era of very accurate and inexpensive freq references. How much is related to
the generation?
Controlling the line frequency is a giant PLL, with horrible complications.
The simple setup for a big generator is that if
All:
Some crude approximations.
Generators that I know of do in fact have a negative slope of frequency
versus load. This is deliberate, to enable stable load sharing.On
small systems, you try to set the slopes proportional to load capacity
so that load sharing remains proportional in
In message 77A742979E2849FD9CA585192F2F5AFC@pc52, Tom Van Baak writes:
For tau 0.01 to 0.3 s it would take more work to quantify which pieces are
contributing to the instability pie.
It doesn't really make sense to talk about taus less than approx
0.1s for Mains.
It is not atypical to see 10%
Hi
I spent a lot of time with a sine wave input on this sort of stuff… You can
come up with a line that the floor must be below. Find a better source and that
line moves down. You can’t find the actual floor. You can only establish that
it must be below this or that level. It’s not like the
HI
There is no way to tell that the “clean” 60 Hz is actually clean. It’s got a
noise component in it. The noise actually is surprisingly high. The picPET is
actually a bit better than that plot would suggest. You can say that the noise
of the picPET is below the “clean” line and move on, but
Em 19/11/2013 09:31, Poul-Henning Kamp escreveu:
In theory harmonic distortion does not change your zero-crossings,
The odd ones doesn´t, but the even ones do... and they happen.
Daniel
___
time-nuts mailing list -- time-nuts@febo.com
To
Alternatively you can put mains through a 40-60 or 50-70 Hz
bandpass filter to suppress anything but the fundamental
The problem with any filtering is precisely that the phase shift through any
filter is highly dependent on the actual signal frequency, so if your purpose
is timing, the filter
Filter families that aim for super flat passbands and super steep skirts
have the craziest phase response. They also ring like a bell when hit
with impulses.
Other filter families aim for well controlled phase response but give up
flat passbands and super steep skirts. They do not ring like a
Magnus,
I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to
see the results of the professional I-Q demodulated gear that you mentioned.
Can you post raw data, or a sample plot?
I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is
going to
Hi
Let’s hope Santa does not bring you an X10 power line based remote control
system for Christmas….
Bob
On Nov 18, 2013, at 5:15 PM, Tom Van Baak t...@leapsecond.com wrote:
Magnus,
I'm going to push back a bit on your mains sampling claim. Mostly, I'd like
to see the results of the
Tom,
Don't confuse everybody with facts, we had a good thread going :)
The PicPet is holding its own very well in that application.
I am surprised at the effect of the laptop supply. I would have certainly
expected effect on phase noise (smaller taus), but not that close to the
carrier. Do
tom,
nice plots. how do you figure out what the contribution of variability vs
noise? In other words there is a differential between the ideal and the
actual a dev curves... is there a way to tease out how much nose contribute
to that differential? It does seem to me that there should be far
Hi
An “ideal” curve would go to the bottom of the scale as soon as the plot
started. Anything that shows on the ADEV curve is by definition noise. The
slope of the ADEV curve can help you determine what sort of noise it is. The
slope(s) on an modified ADEV curve can do that slightly better.
I meant ideal at the noise floor of the picPET (i.e in this case the
generated 60Hz).
On Mon, Nov 18, 2013 at 8:08 PM, Bob Camp li...@rtty.us wrote:
Hi
An “ideal” curve would go to the bottom of the scale as soon as the plot
started. Anything that shows on the ADEV curve is by definition
The power supply contribution is interesting. This might have been a useful
tool when a year ago I was playing with some very large inverters on a
microgrid. I had one inverter as master (in UF mode) and two others as
grid-connected slaves in PQ mode. The first slave would come online just
Hi
There is no way to come up with the noise floor of the picPET from that plot.
In fact coming up with the floor of a single channel device like the picPET is
not all that easy. First you need an ideal noise free sine wave signal …. I’ve
spent more than a few hours on that particular project
ok Bob,
Then how do you tease out the difference between the clean generated 60Hz
and the mains 60Hz adev curves to determine what is noise and what is the
variability in the 60Hz? That is the point of my question not semantics
about ideal vs non-ideal.
doc
On Mon, Nov 18, 2013 at 8:36 PM,
John says:
However I would most humbly point out that the cost of software is not
zero if the time-nutter places any value on his or her time.
Might I point out that the needs and goals of the hobbyist and the professional
are often at odds? The professional needs a solution. The hobbyist
Agree. Luckily, I am good at what I do for a living. If this type stuff
was my job I suspect I would either be out of work or paid very poorly.
Electronics and time are very taxing on my brain.. which is why I play
with them. I specifically avoided these things as a career path because
they
://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
--
Message: 2
Date: Sat, 16 Nov 2013 23:21:07 -0500 (EST)
From: johncr...@aol.com
To: time-nuts@febo.com
Subject: Re: [time-nuts] Mains frequency (Tom Van Baak)
Message-ID
You can get some idea of industrial productivity if you can estimate
and remove non-industrial loads, perhaps by comparing weekends to
work weeks. The dip during working hours and the rise at 4-5 AM are
proportional to the total power used, for the same generating
capacity.
The business of
Not on the eastern grid, but I had hook my picpet ac mains logger back to the
southwest grid if that would be of any help.
On Nov 15, 2013, at 7:51 PM, Bill Dailey docdai...@gmail.com wrote:
I have my picpet faithfully measuring grid frequency and was wondering if
anyone else if the eastern
On 11/16/2013 08:55 AM, Kevin M. Rosenberg wrote:
Not on the eastern grid, but I had hook my picpet ac mains logger back to the
southwest grid if that would be of any help.
They are separated, so they are not phase coherent. Texas is it's own
grid too.
Cheers,
Magnus
On Nov 15, 2013, at 7:51
Your method tosses out a lot of data. You can't see transients. Ideally
rather then record a 1 second average you'd record the time of EVERY zero
crossing. It sounds like a lot of data but not really. You only record
32 bits 60 times each second. That is 240 bytes per second.
On Fri, Nov
Understood.. I have it every 6 cycles now to sync up with his
synchrophaser. I wrote the script so I can specify the number of cycles I
average. Right now it is at 6 because his measures are every 0.1s.
On Sat, Nov 16, 2013 at 2:52 AM, Chris Albertson
albertson.ch...@gmail.comwrote:
Your
On 11/16/2013 09:52 AM, Chris Albertson wrote:
Your method tosses out a lot of data. You can't see transients. Ideally
rather then record a 1 second average you'd record the time of EVERY zero
crossing. It sounds like a lot of data but not really. You only record
32 bits 60 times each
rough comparison... I didnt have my interval right for this set.
https://www.dropbox.com/s/1gi5tbf96yop5hz/stonercompare.JPG
On Sat, Nov 16, 2013 at 3:02 AM, Bill Dailey docdai...@gmail.com wrote:
Understood.. I have it every 6 cycles now to sync up with his
synchrophaser. I wrote the
Here is a real-time map of mains frequency
http://fnetpublic.utk.edu/gradientmap.html
A common way to measure this is to connect a 9 volt AC plug-in power supply
to the DCD pin of a serial port and let the PPS system log and time stamp
each cycle. You can do it no more hardware than the
would probably be an interesting comparison. I am working with a guy on
the eastern grid part now.
You arent using python for processing on the pc are you? If so, I would be
interested in your script. I am trying to verify I am not a just a little
off with mine.
Bill
On Sat, Nov 16, 2013 at
Random noise always converts into time jitter. It doesn't
matter how much you amplify the input signal, noise can push
the detected zero crossing wherever it wants to.
-Chuck Harris
Magnus Danielson wrote:
On 11/16/2013 09:52 AM, Chris Albertson wrote:
Your method tosses out a lot of data.
The signal is 120 volts. You hardly need to amplify it. Clip it with a
diode to +- 9 volts so as not to blow up your serial port. But I'd use a
transformer for safety. The zero crossing detectors are built into the
RS232 interface.You take advantage of the RS232 spec which has a DCD
pin
My purpose is to do it with a picpet. That's it. So, that eliminates a bunch
of the options. I can decouple the measurements from the pc clock that way.
Doc
Sent from mobile
On Nov 16, 2013, at 11:26 AM, Chris Albertson albertson.ch...@gmail.com
wrote:
The signal is 120 volts. You
On 11/16/2013 03:13 PM, Chuck Harris wrote:
Random noise always converts into time jitter. It doesn't
matter how much you amplify the input signal, noise can push
the detected zero crossing wherever it wants to.
You are missing that you can alter how much trigger jitter you get.
Cheers,
Doc,
I measure mains time frequency with a picPET all the time. In fact that's one
of the reasons I designed it. If you're having any trouble contact me by email.
/tvb (i5s)
On Nov 16, 2013, at 11:23 AM, Bill Dailey docdai...@gmail.com wrote:
My purpose is to do it with a picpet. That's
No trouble. Easy. I love it. Keeping track of the rolling counters was a
hack because I am so far removed from serious programming.
Sent from mobile
On Nov 16, 2013, at 1:53 PM, Tom Van Baak (lab) t...@leapsecond.com wrote:
Doc,
I measure mains time frequency with a picPET all the
No, I meant the purpose of the whole thing. Why are you measuring power
frequency? Not why are you using a PIC.How will the data be used, what
is the question driving the measurement?
On Sat, Nov 16, 2013 at 11:23 AM, Bill Dailey docdai...@gmail.com wrote:
My purpose is to do it with a
On Sat, Nov 16, 2013 at 09:26:10AM -0800, Chris Albertson wrote:
The signal is 120 volts. You hardly need to amplify it.
I tried this a slightly different way. Since there is mains noise
everywhere, I made a small loop and connected it to a 3.5mm jack
and then plugged that into the mic socket
There is no higher purpose actually. I just fiddle. This is how I relax.
On Sat, Nov 16, 2013 at 3:47 PM, Chris Albertson
albertson.ch...@gmail.comwrote:
No, I meant the purpose of the whole thing. Why are you measuring power
frequency? Not why are you using a PIC.How will the data be
Only if the noise in question comes from the trigger electronics.
In the case of a 60Hz mains derived signal, most of the noise is
going to be riding on the signal, and will be amplified with your
gain stage. A -delta amplitude noise signal will be zero when the
sine wave signal is at +delta.
Chuck wrote:
In the case of a 60Hz mains derived signal, most of the noise is
going to be riding on the signal, and will be amplified with your
gain stage.
The potential evils of bandpass filters in a timing chain are well
known, but as long as you can accept the delay of a filter (or
-nuts] Mains frequency
Chuck wrote:
In the case of a 60Hz mains derived signal, most of the noise is
going to be riding on the signal, and will be amplified with your
gain stage.
The potential evils of bandpass filters in a timing chain are well
known, but as long as you can accept
Tom,
On 11/17/2013 03:02 AM, Tom Van Baak wrote:
Charles, et al.
I think we agree. Just to clarify...
I rely on no hardware and no software filters when I use a time-stamping
counter such as a sub-nanosecond Pendulum CNT-9x or sub-microsecond picPET.
An electrical zero-crossing happens
Again, why are you measuring the AC line? I'd think maybe to measure the
noise that is on it. The fundamental freq. changes second by second.
It's not a clean 60Hz my any means. The rate of frequency change is one
thing you'd like to measure
I was just watching a minute ago and can see a
On 11/17/2013 03:33 AM, Chris Albertson wrote:
Again, why are you measuring the AC line? I'd think maybe to measure the
noise that is on it. The fundamental freq. changes second by second.
It's not a clean 60Hz my any means. The rate of frequency change is one
thing you'd like to measure
When you measure the mains signal, nominally 60 Hz in this case, spikes
etc. is noise which is local and not of interest when comparing over a
large area. Inter-area oscillations have much slower properties.
If you go the time-stamping way, you *should* remove such noise.
Removing or
Again, why are you measuring the AC line? I'd think maybe to measure the
noise that is on it. The fundamental freq. changes second by second.
It's not a clean 60Hz my any means. The rate of frequency change is one
thing you'd like to measure
I was just watching a minute ago and can see a
For a non Time-Nuts application, I needed a narrow bandpass filter that would
provide essentially zero phase shift (no more than 10 or 20uS was desired) over
a frequency range of 55 to 65 Hz while providing useful reduction of the
harmonics, particularly in the range of 400 to 1kHz. This was to
Does an ac transformer hurt me? I was looking for that dang megohm page when I
started this. Couldn't find it so I used a transformer.
Doc
Sent from my iPad
On Nov 16, 2013, at 9:17 PM, Tom Van Baak t...@leapsecond.com wrote:
Again, why are you measuring the AC line? I'd think maybe to
Turns out that professional gear for this does not do time-stamping in
this regard. Rather, they I-Q demodulate the signal with a reference
signal at the nominal rate, low-pass filter it and pay attention to
details of filtering like group-delay and compensation thereof.
It makes sense to me.
tvb wrote:
I think we agree. Just to clarify...
I rely on no hardware and no software filters when I use a
time-stamping counter such as a sub-nanosecond Pendulum CNT-9x or
sub-microsecond picPET. An electrical zero-crossing happens when it
happens. If you filter you're just trying to
This resonates with me somewhat since I used to run nuclear power plants and
operate the actual turbines. It does seem that the time interval measurements
have much more jitter than I would expect. I suspect the thousands of turbines
phase locked may introduce all kinds of very subtle
Tom -
I just had to comment---
Both assume some reasonable limit of mains df/f/dt. You can either
do it with a fancy $100 to $1000 reference signal generator + PLL or FLL + IQ
detector + professional box -- or with a $1 PIC and $0 s/w.
/tvb
You are of course correct. However I would
I have my picpet faithfully measuring grid frequency and was wondering if
anyone else if the eastern grid has a live measure to compare to?
110vac--5vac--100ohm--picpet event--- python average 60 cycles-- log freq
every second.
Sent from mobile
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