[time-nuts] Patek Phillipe mechanical clock
My 5065A has one of those tick-monsters in it. You can hear the damn thing two states away (three at night). Luckily it powers up disabled, but once you enable it you can't stop it. I've only enabled it once... that was enough... lesson learned. > I hear they are quite annoying clunkers actually. I have never owned one but a fellow in Europe was telling me you can really here them tick. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] BTTF : Austron 1210-C Crystal Clock
Hi Jim, Maybe a version of this?: http://leapsecond.com/history/Benchmark.htm The audible (1 kc) whine was probably from the model 113 or 115. See if any of the following pages remind you: http://leapsecond.com/hpclocks/ http://www.radiomuseum.org/r/hewlett_pa_frequency_divider_and_cl.html http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1959-11.pdf http://hpmemoryproject.org/wb_pages/wall_b_page_01.htm http://hpmemoryproject.org/news/2012/vintage_01.htm /tvb - Original Message - From: "Jim Harman" To: "Discussion of precise time and frequency measurement" Sent: Sunday, June 11, 2017 7:43 PM Subject: Re: [time-nuts] BTTF : Austron 1210-C Crystal Clock > On Sun, Jun 11, 2017 at 9:01 PM, paul swed wrote: > >> But perhaps whats magical gold is the Patek Phillipe clock movement. Just a >> guess.I hear they are quite annoying clunkers actually. I have never owned >> one but a fellow in Europe was telling me you can really here them tick. >> > > In my first job back in 1973 I inherited a lab that included what must have > been an HP 100C frequency reference. It took up most of a rack and divided > down a 100KHz oscillator with cascaded injection-locked 10:1 multivibrators > that used metal octal-base tubes. The final frequency of 100 Hz drove a > beautiful clock that made a very audible whine when it was working. This > must have been an option because I don't see any reference to it in the > 100C manual. > > At the bottom of the rack was a Hammarlund radio to tune in WWV for > calibration. > > IIRC the clock motor also drove an adjustable cam and microswitch. The > receiver's audio was fed through the switch. I think the idea was that you > could accurately measure the oscillator drift by adjusting the phase of the > cam until you could hear WWV's tick during the short time the switch was > closed. > > > -- > > --Jim Harman ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] BTTF : Austron 1210-C Crystal Clock
On Sun, Jun 11, 2017 at 9:01 PM, paul swed wrote: > But perhaps whats magical gold is the Patek Phillipe clock movement. Just a > guess.I hear they are quite annoying clunkers actually. I have never owned > one but a fellow in Europe was telling me you can really here them tick. > In my first job back in 1973 I inherited a lab that included what must have been an HP 100C frequency reference. It took up most of a rack and divided down a 100KHz oscillator with cascaded injection-locked 10:1 multivibrators that used metal octal-base tubes. The final frequency of 100 Hz drove a beautiful clock that made a very audible whine when it was working. This must have been an option because I don't see any reference to it in the 100C manual. At the bottom of the rack was a Hammarlund radio to tune in WWV for calibration. IIRC the clock motor also drove an adjustable cam and microswitch. The receiver's audio was fed through the switch. I think the idea was that you could accurately measure the oscillator drift by adjusting the phase of the cam until you could hear WWV's tick during the short time the switch was closed. -- --Jim Harman ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] BTTF : Austron 1210-C Crystal Clock
Hi Greg, > Leap Second has a series of photos. > http://www.leapsecond.com/museum/au1210/ That would be me. There are quite a few versions of the Austron 1210 Crystal Oscillator, at least models A through D, as I tried to show on that page. I have a few and they are handy instruments, with a vintage appeal. > BUT at $900 ... seller in King George, VA obviously thought he found gold. > ** must be heat exhaustion ** Ha! You think you're joking -- but what you're missing is that this version has the rare and valuable Patek Philippe analog clock. Perhaps you have also seen these beautiful electro-mechanical Patek movements on the early models of hp 5065A and hp 5061A frequency standards. Yes, even -hp- used them for their precious atomic clocks; that's how respectable and reliable these Patek mechanical impulse movements are. It's a highly desirable clock display because not only is it of interest to the bottom-feeding collectors of vintage electronic T&F gear (like we time-nuts) but it's also of high-value to collectors of anything Patek Philippe (like the private jet and private island crowd). It's a rare cross between engineering and art; between function and fashion; between electronics and elegance; between history and who cares. I first ran into this phenomenon years ago when innocently searching for words like 5065 clock. Yes, there were some hp rubidium vapor clocks, but there were also some mechanical wrist watches with the same model number -- but for more than ten times the price! That's when I knew that being a time-nut was a far cheap hobby compared to designer wrist-watches. The latter is an utterly massive industry with per-item prices in the 1e4, 1e5 and even 1e6 dollar range. It's what allows a time-nut to say: Honey, I bought a 5065 yesterday and saved $14,000! To get a better idea, take a few eye candy moments: 1) You've never seen so many cool-looking electronic clocks: https://www.google.com/search?tbm=isch&q=patek-philippe-electronic-tower-master-clock 2) A very nice Patek Philippe Master Clock System that sold for a mere $125,000: http://www.christies.com/lotfinder/Lot/patek-philippe-an-integrated-electronic-master-clock-5864933-details.aspx 3) Recent eBay auction. The Patek clock stepper movement alone: http://www.ebay.com/itm/191026418966 4) I'm not joking about the "5065". Take your pick -- $1,500 or $23,000: http://www.ebay.com/itm/252922060868 http://www.ebay.com/itm/201889713477 5) A collection of Patek photos I grabbed over the years: http://leapsecond.com/museum/patek/ So, now you know why the eBay seller of http://www.ebay.com/itm/282490626815 is not suffering from heat exhaustion. If nothing else, his item is cheaper (and far less shipping costs) than this one: http://www.ebay.com/itm/282495468972 /tvb - Original Message - From: "Gregory Beat" To: Sent: Sunday, June 11, 2017 5:24 PM Subject: [time-nuts] BTTF : Austron 1210-C Crystal Clock > BTTF : Back to the Future "moment" > > Austron was a company based in Austin, TX that manufactured crystal clocks > for military and industry in late 1970s. Leap Second has a series of photos. > http://www.leapsecond.com/museum/au1210/ > > Austron 1210-D Manual (digital model) > Product produces 1 MHz and 5 MHz sine wave. > http://www.to-way.com/tf/1210D.pdf > > Used Austron 1210-C appeared on eBay, auction # 282490626815 > BUT at $900 ... seller in King George, VA obviously thought he found gold. > ** must be heat exhaustion ** > > greg > Sent from iPad Air ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] BTTF : Austron 1210-C Crystal Clock
On 6/11/17 6:37 PM, Bob kb8tq wrote: Hi The new age drill on anything unusual on eBay seems to be to start it out at $10,000 and lower it 5% every six months. Eventually you will hit the “right” price. Apparently it is much easier to do this than to actually research the item you have. I’ve always wondered how these guys deal with the inventory costs of waiting 20 years to sell something …. A Dutch Auction ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] BTTF : Austron 1210-C Crystal Clock
Hi The new age drill on anything unusual on eBay seems to be to start it out at $10,000 and lower it 5% every six months. Eventually you will hit the “right” price. Apparently it is much easier to do this than to actually research the item you have. I’ve always wondered how these guys deal with the inventory costs of waiting 20 years to sell something …. Bob > On Jun 11, 2017, at 8:24 PM, Gregory Beat wrote: > > BTTF : Back to the Future "moment" > > Austron was a company based in Austin, TX that manufactured crystal clocks > for military and industry in late 1970s. Leap Second has a series of photos. > http://www.leapsecond.com/museum/au1210/ > > Austron 1210-D Manual (digital model) > Product produces 1 MHz and 5 MHz sine wave. > http://www.to-way.com/tf/1210D.pdf > > Used Austron 1210-C appeared on eBay, auction # 282490626815 > BUT at $900 ... seller in King George, VA obviously thought he found gold. > ** must be heat exhaustion ** > > greg > Sent from iPad Air > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] BTTF : Austron 1210-C Crystal Clock
Greg Ebay can always be sort of silly. ah for the old days when a rusty piece of stuff might go for a reasonable $. But perhaps whats magical gold is the Patek Phillipe clock movement. Just a guess.I hear they are quite annoying clunkers actually. I have never owned one but a fellow in Europe was telling me you can really here them tick. Regards Paul WB8TSL On Sun, Jun 11, 2017 at 8:24 PM, Gregory Beat wrote: > BTTF : Back to the Future "moment" > > Austron was a company based in Austin, TX that manufactured crystal clocks > for military and industry in late 1970s. Leap Second has a series of > photos. > http://www.leapsecond.com/museum/au1210/ > > Austron 1210-D Manual (digital model) > Product produces 1 MHz and 5 MHz sine wave. > http://www.to-way.com/tf/1210D.pdf > > Used Austron 1210-C appeared on eBay, auction # 282490626815 > BUT at $900 ... seller in King George, VA obviously thought he found gold. > ** must be heat exhaustion ** > > greg > Sent from iPad Air > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] BTTF : Austron 1210-C Crystal Clock
BTTF : Back to the Future "moment" Austron was a company based in Austin, TX that manufactured crystal clocks for military and industry in late 1970s. Leap Second has a series of photos. http://www.leapsecond.com/museum/au1210/ Austron 1210-D Manual (digital model) Product produces 1 MHz and 5 MHz sine wave. http://www.to-way.com/tf/1210D.pdf Used Austron 1210-C appeared on eBay, auction # 282490626815 BUT at $900 ... seller in King George, VA obviously thought he found gold. ** must be heat exhaustion ** greg Sent from iPad Air ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Control Systems (was: uC ADC resolution)
Hi > On Jun 11, 2017, at 2:21 PM, Chris Albertson > wrote: > > On Sun, Jun 11, 2017 at 9:28 AM, Attila Kinali wrote: > >> Hi, >> > > >> >> You are asking a lot of question regarding control systems. >> But, there are no easy answers there. Especially if you want >> to build it cheap. The cheaper you want to be the more you >> need to know and understand the problem. >> > > This has been my opinion for a LONG time. It is easy to come up with good > solutions if to just throw money at the problem.So you see here people > proposing just going top of the line all across but an engineer earns his > money > by comping up with cost effective solutions that meet all the stated > requirements. > > This is my interest in mechanics too. Can a $200 3D printed plastic robot > arm > with poor absolute repeatability place an M6 screw into an M6 nut? > Certainly > not if it runs open loop. But what if you add visual feedback? > Yes everything requires more expertise if you reduce the budget > > So you understand my questions are all like this: "If you back down from > top of the line solution how does that effect real world performance?" > No one answers. > Would it help if each and every time we answered “that depends”. This is always the real answer to any real world engineering problem. Quantifying and qualifying *all* the dependencies is what people get paid to do for a living. There is *always* both theoretical and experimental work involved. There is never a simple one line answer. If you want the more detailed answer, start digging into it. Try this and that. Measure what you see. Report your results and we’ll help you analyze them. Often this spirals instead into a game of liars poker. I can do it for $100, he can do it for $10, somebody else can do it for $1, the next guy is at $0.10 and we are at $0.01 in no time. There is no data, not qualification of anything, just a bunch of random cost numbers. That’s not how things work on any real design I’ve ever seen. Raw cost per unit, time / cost to implement, margin requirements, volume of production, and performance are all tightly related to each other. Until you nail all that down, talking about a price per unit does not make any sense. As an example, we are talking here about OCXO’s. Can you build a ten cent OCXO? Sure you can. It only takes a well stocked junk box of “free” parts. Can you spend a few years tweaking the one uint for performance, indeed yes again. Is it still a ten cent OCXO after you spend a year of your time tweaking it? Would you sell someone a year of your time for ten cents? Would you build, test, and sell somebody a thousand of them for ten cents each? Bob > >> >> I suggest you reading an introductory text into control systems >> like e.g. "Feedback Control of Dynamic Systems", by Franklin, Powell, >> Emami-Naeini. > > > > > -- > > Chris Albertson > Redondo Beach, California > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] E1938 oven design
Hi I certainly saw the “positive gain at this setting” going to “negative gain at that setting” result on a lot of OCXO designs. I never had the patience (or a stable enough system) to get into the millions or even 100K’s on a single oven. As a practical result, a gain of -500 is not really any better or worse than a gain of +500. It *can* be a bit confusing to set up though …. Bob > On Jun 11, 2017, at 1:43 PM, Richard (Rick) Karlquist > wrote: > > > > On 6/11/2017 8:59 AM, Attila Kinali wrote: > >>> The exact insulation is relatively unimportant. >>> We even tried still air using a knife edge >>> cradle. Didn't make much difference. > > >> What is a knife edge cradle? > > We wanted to test still air as insulation. > We couldn't just replace the insulation with > "nothing". There had to be some kind of mechanical > support to keep the oven mass suspended inside the > outer case. Our ME built a skeleton framework > made of plastic to support it. In order to minimize > conduction thru the plastic, he designed in knife > edges where the plastic came into contact with the > oven mass. > > >> One big question remains: How did you set the ratio >> between face and rim heater? Was it determined at design >> time and then just set the same for all units or was >> it part of the production test? > > During proof of concept phase in R&D, I peaked up the > thermal gain on each unit by trial and error. I could > usually get a run with positive thermal gain, then > increment the ratio, and get a run with negative > thermal gain. I could then interpolate to get the > ratio that should give "infinite" gain. Maybe one > or two more runs after that would get me to where > the gain passed through infinity at some ambient > temperature, and was well into the millions over the > whole range. At extremely high thermal gain, the > gain is not constant over ambient temperature. > > I collected data on a number of units and then used > the average ratio as the production setting. I > checked production units from time to time and they > typically ran well in the 100's of thousands for gain. > > This compromise was workable because we individually > programmed the oven set point to the exact turnover > temperature. This is a lot easier because it doesn't > require environmental chamber runs. The E1983A software that > I "leaked" to the time-nuts community I believe has a > command that can be used to search for the turnover. > > > Rick N6RK > >> Attila Kinali > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Control Systems (was: uC ADC resolution)
On Sun, 11 Jun 2017 11:21:15 -0700 Chris Albertson wrote: > This has been my opinion for a LONG time. It is easy to come up with good > solutions if to just throw money at the problem.So you see here people > proposing just going top of the line all across but an engineer earns his > money > by comping up with cost effective solutions that meet all the stated > requirements. Yes, I have done plenty of that. If the production run will be >100k then it's well worth spending a month or two to shave off 1€. But on a small volume project, or even worse a one-off project, I am not going to try save 10€ if I that would cost me a day of reading and doing calculations. > So you understand my questions are all like this: "If you back down from > top of the line solution how does that effect real world performance?" > No one answers. Because there are no easy answers. What you are asking requires someone sitting down and do the math (or simulations) and figure out what the limiting parameters are, when restricting the design in this or that way. To give this a little perspective: For one of my many side-projects, I do need an DAC with a very high resolution (>23bit). It took me a few days to figure out that I really need this resolution and cannot do with anything lower. I have probably poured another 3-4 (man)weeks just calculating and simulating different designs that looked promising enough to deliver the needed performance. I have settled on two designs I want to try, but I am still reading up on different issues and refining the design for those. I guess it will take me another (man)month or two until I a can say with confidence that the design is good, will with high probability deliver the performance I need and there are no easy ways to improve it. And then I will start the implementation (ie schematics, layout and software). Like you asked for your temperature control loop, I could have asked how to build such a DAC. But I would not have gotten any answer. Because there simply isn't anyone who knows the answer. At least not for a design with my constraints. If you read carefully what I have asked on time-nuts and volt-nuts in the last half year or year, you will find quite a few of my questions relate to this project in some way or other. Questions on how to do this or that. Questions on whether X is possible or not and if yes, under what conditions. To some questions I got answers, to others I didn't. If I didn't get an answer, I knew that the question is difficult and tried to read up on it as much as I could manage. I do not know, whether it does look like answering questions on time-nuts is easy. At least for me it isn't. I came here 10 or 11 years ago. For over a year I didn't write anything, but just read. Then I ventured my opinion on things I thought I knew and started asking small questions here and there (if you want to have some fun, go back and read what I wrote 8-9 years ago... I was sooo naive...). In the meantime I continued reading up on different things as time allowed. It really took me full 10 years to reach the level I am at now, but I still do not know anything. My knowledge is full of holes and things I think I understood but didn't (the construction of the E1938 is a nice recent example of that). There are whole areas I have no clue about at all (e.g. how to build low noise oscillators, or how ADEV, MDEV & co actually work) and I know it will take me years to gain a sufficient understanding of those. Answering, even simple questions, can take me easily half an hour. I often have to go back to my documents and paper collection to check things, as I am unable to remember everything in detail. Then writing a (hopefully) intelligeble answer is also something that shouldn't be underestimated. Hmm.. this ended being up longer than I intended it to be. Sorry about that. But I hope I made my point clear. If not: TL;DR: Some questions are just difficult and need someone to sit down and think hard before they can be answered. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Control Systems (was: uC ADC resolution)
On Sun, Jun 11, 2017 at 9:28 AM, Attila Kinali wrote: > Hi, > > > You are asking a lot of question regarding control systems. > But, there are no easy answers there. Especially if you want > to build it cheap. The cheaper you want to be the more you > need to know and understand the problem. > This has been my opinion for a LONG time. It is easy to come up with good solutions if to just throw money at the problem.So you see here people proposing just going top of the line all across but an engineer earns his money by comping up with cost effective solutions that meet all the stated requirements. This is my interest in mechanics too. Can a $200 3D printed plastic robot arm with poor absolute repeatability place an M6 screw into an M6 nut? Certainly not if it runs open loop. But what if you add visual feedback? Yes everything requires more expertise if you reduce the budget So you understand my questions are all like this: "If you back down from top of the line solution how does that effect real world performance?" No one answers. > > I suggest you reading an introductory text into control systems > like e.g. "Feedback Control of Dynamic Systems", by Franklin, Powell, > Emami-Naeini. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] uC ADC resolution (was: Poor man's oven)
On 6/11/2017 6:09 AM, Magnus Danielson wrote: Hi, What papers would you recommend reading? One of the things that we experimented on and improved was the passive wall to prohibit quick cooling of oven. A puff of air or the forced convection (fans) needed for other electronics would tie the metal shield very well to surrounding environment. Using a simple plastic wall/box as a windshield has a quite drastic effect at the rate of change in temperature, and allowed the oven to react better to it. It has proven a very good strategy to reduce the systematic effect that eats up stability. As systematic effect, it should not be part of ADEV, but if you ADEV it is there loud and clear. Cheers, Magnus On the E1938A, we tried externally cooling it by spraying it with canned "freeze mist" and there was no observable fluctuation in crystal temperature using the crystal in B mode (20 ppm/degree C). Rick N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] E1938 oven design
On 6/11/2017 8:59 AM, Attila Kinali wrote: The exact insulation is relatively unimportant. We even tried still air using a knife edge cradle. Didn't make much difference. What is a knife edge cradle? We wanted to test still air as insulation. We couldn't just replace the insulation with "nothing". There had to be some kind of mechanical support to keep the oven mass suspended inside the outer case. Our ME built a skeleton framework made of plastic to support it. In order to minimize conduction thru the plastic, he designed in knife edges where the plastic came into contact with the oven mass. One big question remains: How did you set the ratio between face and rim heater? Was it determined at design time and then just set the same for all units or was it part of the production test? During proof of concept phase in R&D, I peaked up the thermal gain on each unit by trial and error. I could usually get a run with positive thermal gain, then increment the ratio, and get a run with negative thermal gain. I could then interpolate to get the ratio that should give "infinite" gain. Maybe one or two more runs after that would get me to where the gain passed through infinity at some ambient temperature, and was well into the millions over the whole range. At extremely high thermal gain, the gain is not constant over ambient temperature. I collected data on a number of units and then used the average ratio as the production setting. I checked production units from time to time and they typically ran well in the 100's of thousands for gain. This compromise was workable because we individually programmed the oven set point to the exact turnover temperature. This is a lot easier because it doesn't require environmental chamber runs. The E1983A software that I "leaked" to the time-nuts community I believe has a command that can be used to search for the turnover. Rick N6RK Attila Kinali ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Control Systems (was: uC ADC resolution)
Hi, On Sat, 10 Jun 2017 13:10:39 -0700 Chris Albertson wrote: > How many output bits are required? Most uPs have quite a few digital > output pins. Each pin could drive a heater resister. Values of the > resisters organized by power of two. Again note the title (poor mans...) > resisters cost almost zero. Even of driver transistors are needed you'd > get change back from a dollar bill. You are asking a lot of question regarding control systems. But, there are no easy answers there. Especially if you want to build it cheap. The cheaper you want to be the more you need to know and understand the problem. I suggest you reading an introductory text into control systems like e.g. "Feedback Control of Dynamic Systems", by Franklin, Powell, Emami-Naeini. That should answer 90% of your questions, if not more. If you want to go into details of digital control systems, a book like the one by Landau/Zito "Digital Control Systems" will fill the gaps. If you have never heard anything about Laplace and z-Transformation, then I highly suggest reading the first few chapters of "Linear Systems and Signals" by Lathi (and keep it as a reference), before you start with any control theory book. There is really no easy way around learning this stuff if you want to build a control system that does more than just "barely work". You don't need to apply all the fancy methodology, people have developed over the years, in most cases. But even just getting a simple PI-loop working correctly without oscillation requires a few calculations. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] E1938 oven design
On Thu, 8 Jun 2017 16:17:20 -0700 "Richard (Rick) Karlquist" wrote: > We were stuck under 1,000 for a long time > using only face heaters. I still remember the > day that I rigged up the first crude rim header > by winding a piece of magnet wire around the rim > and holding it in place with 5 min epoxy. I > didn't know what else to try. This seemed like > a Hail Mary play at the time, until I > measured the gain. We instantly went to gains > above 20,000. It seemed high at the time but > it was only the beginning. > > The exact insulation is relatively unimportant. > We even tried still air using a knife edge > cradle. Didn't make much difference. What is a knife edge cradle? One big question remains: How did you set the ratio between face and rim heater? Was it determined at design time and then just set the same for all units or was it part of the production test? Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] uC ADC resolution (was: Poor man's oven)
Hi
A great starting point is Rick’s paper on the Hockey Puck.
Bob
> On Jun 11, 2017, at 9:09 AM, Magnus Danielson
> wrote:
>
> Hi,
>
> What papers would you recommend reading?
>
> One of the things that we experimented on and improved was the passive wall
> to prohibit quick cooling of oven. A puff of air or the forced convection
> (fans) needed for other electronics would tie the metal shield very well to
> surrounding environment. Using a simple plastic wall/box as a windshield has
> a quite drastic effect at the rate of change in temperature, and allowed the
> oven to react better to it.
> It has proven a very good strategy to reduce the systematic effect that eats
> up stability. As systematic effect, it should not be part of ADEV, but if you
> ADEV it is there loud and clear.
>
> Cheers,
> Magnus
>
> On 06/11/2017 04:45 AM, Bob kb8tq wrote:
>> Hi
>>
>> One of the bigger unknowns in all this is how tight your control point
>> needs to be held
>> in order that your crystal only sees 0.1C. So far we have sort of assumed
>> that the
>> control point and the crystal see the same thing. That’s never the case.
>>
>> If the outside temperature goes from -30 to +70 (100C range), a 0.1 C change
>> would
>> be a thermal gain of 1,000. A +/- 0.1 C change would be a thermal gain of
>> 500. Both
>> are pretty respectable numbers for a basic single oven.
>>
>> It is not at all uncommon to see references to “0.0001C temperature control”
>> (or some
>> looney number) on ovens that obviously do not have a thermal gain of much
>> over 100.
>> Yes, those references were a lot more common 40 years ago than they are
>> today. The
>> take away is that often set point control is much tighter at the sensor than
>> at the crystal.
>>
>> It is not uncommon for people to ask “what is the control at a constant
>> ambient (room
>> conditions maybe). The answer is inevitably a very small change. If your
>> room varies
>> by 1 C and you have a thermal gain of 1,000, the oven changes by 0.001C. If
>> your room
>> changes by 0.1 C then the oven would change by 0.0001 C. Inevitably the
>> phrase “plus
>> circuit noise” needs to be added in there somewhere as the numbers get ever
>> smaller.
>> ADEV is a more common way to look at controller noise than TC.
>>
>> As I keep pointing out, there are some good papers on all of this. I claim
>> absolutely
>> no original insight in any of the above.
>>
>> Bob
>>
>>> On Jun 10, 2017, at 9:11 PM, Hal Murray wrote:
>>>
>>>
>>> albertson.ch...@gmail.com said:
I say "effective" because we can dither the low order bits to gain maybe 6
effective bits form 4 real bits (we can filter the switching noise from a
low frequency dither)
>>>
>>> It's hard to filter low frequencies and the more bits you gain by dithering
>>> the lower the filter you need and the closer in the spurs move.
>>>
>>>
Lets say my goal is regulation within 0.1C. After filtering I have 10
"good" bits in my ADC. That is 1024 counts. My set point is S.
>>>
I scale the ADC so that 0 == (S - 0.5) and 1023 == (S + 0.5)This means
that each ADC count is 0.001 degree C and within the 0.1C range there are
100 ADC counts.
>>>
>>> That's not enough to describe the system so you can decide if it will meet
>>> your 0.1C goal.
>>>
>>> You also need to know the sampling rate, the delay time from heater to
>>> temperature sensor, the PID parameters, and maybe the rate of change of the
>>> environmental temperature and the delay from the environment to your system.
>>> ("delay" should probably be transfer function or impulse response but a
>>> simple exponential is probably good enough.)
>>>
>>>
>>>
>>> --
>>> These are my opinions. I hate spam.
>>>
>>>
>>>
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
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>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>
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Re: [time-nuts] uC ADC resolution (was: Poor man's oven)
Hi,
What papers would you recommend reading?
One of the things that we experimented on and improved was the passive
wall to prohibit quick cooling of oven. A puff of air or the forced
convection (fans) needed for other electronics would tie the metal
shield very well to surrounding environment. Using a simple plastic
wall/box as a windshield has a quite drastic effect at the rate of
change in temperature, and allowed the oven to react better to it.
It has proven a very good strategy to reduce the systematic effect that
eats up stability. As systematic effect, it should not be part of ADEV,
but if you ADEV it is there loud and clear.
Cheers,
Magnus
On 06/11/2017 04:45 AM, Bob kb8tq wrote:
Hi
One of the bigger unknowns in all this is how tight your control point needs
to be held
in order that your crystal only sees 0.1C. So far we have sort of assumed that
the
control point and the crystal see the same thing. That’s never the case.
If the outside temperature goes from -30 to +70 (100C range), a 0.1 C change
would
be a thermal gain of 1,000. A +/- 0.1 C change would be a thermal gain of 500.
Both
are pretty respectable numbers for a basic single oven.
It is not at all uncommon to see references to “0.0001C temperature control”
(or some
looney number) on ovens that obviously do not have a thermal gain of much over
100.
Yes, those references were a lot more common 40 years ago than they are today.
The
take away is that often set point control is much tighter at the sensor than at
the crystal.
It is not uncommon for people to ask “what is the control at a constant ambient
(room
conditions maybe). The answer is inevitably a very small change. If your room
varies
by 1 C and you have a thermal gain of 1,000, the oven changes by 0.001C. If
your room
changes by 0.1 C then the oven would change by 0.0001 C. Inevitably the phrase
“plus
circuit noise” needs to be added in there somewhere as the numbers get ever
smaller.
ADEV is a more common way to look at controller noise than TC.
As I keep pointing out, there are some good papers on all of this. I claim
absolutely
no original insight in any of the above.
Bob
On Jun 10, 2017, at 9:11 PM, Hal Murray wrote:
albertson.ch...@gmail.com said:
I say "effective" because we can dither the low order bits to gain maybe 6
effective bits form 4 real bits (we can filter the switching noise from a
low frequency dither)
It's hard to filter low frequencies and the more bits you gain by dithering
the lower the filter you need and the closer in the spurs move.
Lets say my goal is regulation within 0.1C. After filtering I have 10
"good" bits in my ADC. That is 1024 counts. My set point is S.
I scale the ADC so that 0 == (S - 0.5) and 1023 == (S + 0.5)This means
that each ADC count is 0.001 degree C and within the 0.1C range there are
100 ADC counts.
That's not enough to describe the system so you can decide if it will meet
your 0.1C goal.
You also need to know the sampling rate, the delay time from heater to
temperature sensor, the PID parameters, and maybe the rate of change of the
environmental temperature and the delay from the environment to your system.
("delay" should probably be transfer function or impulse response but a
simple exponential is probably good enough.)
--
These are my opinions. I hate spam.
___
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