Re: [time-nuts] Achievable temperature stability for Thunderboltenvironment? Answer found
Sorry Everyone, The answer is in the LH readme, and I completely overlooked it. /k[?=#] - set temp control parameter '?' Cheers, david Hi All, I've setup a TBolt with a late model oscillator mounted externally to the case, and moved the C version temp sensor from the main PCB to the oscillator. With a little fan, LH is keeping the temperature within about 0.02dC. Amazing, given I have about 10dC ambient variations. How do I start LH with the PID parameters obtained during the autotune (KA)? Which bit of which source file should I look at to figure this out? Thanks to Mark, John, Warren and others for LH! davidh On 17/01/2011 9:49 AM, WarrenS wrote: Here is a Plot of the results, (The post would not accept both pictures at the same time) This is the 'KISS' enclosure and driver I use with Lady Heather's temperature controller that holds the temperature change to under 0.01 deg. I have the box just setting on top of a PC next to the a window. 'KISS' = Keep It Simple and SMALL ... I don't know if this low resolution picture will post correctly. If anyone wants a high resolution view of the H/W, or an expanded plot showing the results over a 2 week period, I can provide them, if someone will send me the name of a site to post them at. ws *** - Original Message - From: "Mark Sims" Sent: Saturday, January 15, 2011 12:53 PM Subject: [time-nuts] Achievable temperature stability for Thunderboltenvironment? Using Lady Heather's temperature controller (fan+cardboard box+solid state relay+baffling and thermal mass to taste) I get around +/- 3 millidegree temperature control when the AC/furnace is not running and +/- 20 millidegrees with them cycling. Long term temperature average is down in the tens of microdegrees. Under ideal conditions, I have seen over an hour where the temperature sensor did not move a single microdegree! The active temperature control has a most definite positive effect on the device performance. I place the power supply in the thermal enclosure to minimize its output temperature coefficient. Yes, the thermal sensor is away from the oscillator module (and power supply) but in the semi-closed environment of the box, the thermal stability on one area is pretty much the same everywhere. I have chosen my box so that if the fan stops (for whatever reason) the temperature in the box still does not exceed 50C. For the ultra best uber performance you need to maximize the quality of all the input and environmental variables (temperature, power, antenna, surveyed location, disciplining parameters, etc) Choose your antenna mask angle and signal level threshold to minimize satellite constellation switching. With a little nutty attention to the details you can get parts per trillion performance out of the little beastie. ** As long as the Tbolt's Osc is being disciplined, I have found: Most Tbolt's with factory default settings (i.e TC = 100) will show minimum effects with standard room temperature changes. No special protection needed. A unit that is tuned a bit better (in a box and TC of 300 to 500), then temperature changes of less than 1 deg / hr will be OK. A better optimized setup with TC settings in the 500 to 1000 sec range, a max temperature rate of change of up to 0.1 deg C per hr will have minimum effect. If you want to go all out time nuts, (with "Special" TC setting above 1000) then best to hold the sensor temperature to within 0.02 deg total change, which can be done using Lady Heather's Temperature controller. How high you can go with the TC setting, depends on many things, such as how stable the Tbolt's Oscillator is. Each setup is different. A TC setting of 1000 sec is generally the max you should go. With this Tbolt, the best results can be obtained with a 'special' TC setting to 2000 to 3000. Attached is the last 2 weeks of a Lady Heather plot, showing a temperature tracking test I did to see how long it takes a Tbolt to learn a new environment. This unit has a Poor antenna, 1 sec ADEV of 1e-12, Aging of 4 e-12 / day, Temp coeff of 2.5e-10 / deg. Have fun ws > ___ 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] Achievable temperature stability for Thunderboltenvironment?
Hi All, I've setup a TBolt with a late model oscillator mounted externally to the case, and moved the C version temp sensor from the main PCB to the oscillator. With a little fan, LH is keeping the temperature within about 0.02dC. Amazing, given I have about 10dC ambient variations. How do I start LH with the PID parameters obtained during the autotune (KA)? Which bit of which source file should I look at to figure this out? Thanks to Mark, John, Warren and others for LH! davidh On 17/01/2011 9:49 AM, WarrenS wrote: Here is a Plot of the results, (The post would not accept both pictures at the same time) This is the 'KISS' enclosure and driver I use with Lady Heather's temperature controller that holds the temperature change to under 0.01 deg. I have the box just setting on top of a PC next to the a window. 'KISS' = Keep It Simple and SMALL ... I don't know if this low resolution picture will post correctly. If anyone wants a high resolution view of the H/W, or an expanded plot showing the results over a 2 week period, I can provide them, if someone will send me the name of a site to post them at. ws *** - Original Message - From: "Mark Sims" Sent: Saturday, January 15, 2011 12:53 PM Subject: [time-nuts] Achievable temperature stability for Thunderboltenvironment? Using Lady Heather's temperature controller (fan+cardboard box+solid state relay+baffling and thermal mass to taste) I get around +/- 3 millidegree temperature control when the AC/furnace is not running and +/- 20 millidegrees with them cycling. Long term temperature average is down in the tens of microdegrees. Under ideal conditions, I have seen over an hour where the temperature sensor did not move a single microdegree! The active temperature control has a most definite positive effect on the device performance. I place the power supply in the thermal enclosure to minimize its output temperature coefficient. Yes, the thermal sensor is away from the oscillator module (and power supply) but in the semi-closed environment of the box, the thermal stability on one area is pretty much the same everywhere. I have chosen my box so that if the fan stops (for whatever reason) the temperature in the box still does not exceed 50C. For the ultra best uber performance you need to maximize the quality of all the input and environmental variables (temperature, power, antenna, surveyed location, disciplining parameters, etc) Choose your antenna mask angle and signal level threshold to minimize satellite constellation switching. With a little nutty attention to the details you can get parts per trillion performance out of the little beastie. ** As long as the Tbolt's Osc is being disciplined, I have found: Most Tbolt's with factory default settings (i.e TC = 100) will show minimum effects with standard room temperature changes. No special protection needed. A unit that is tuned a bit better (in a box and TC of 300 to 500), then temperature changes of less than 1 deg / hr will be OK. A better optimized setup with TC settings in the 500 to 1000 sec range, a max temperature rate of change of up to 0.1 deg C per hr will have minimum effect. If you want to go all out time nuts, (with "Special" TC setting above 1000) then best to hold the sensor temperature to within 0.02 deg total change, which can be done using Lady Heather's Temperature controller. How high you can go with the TC setting, depends on many things, such as how stable the Tbolt's Oscillator is. Each setup is different. A TC setting of 1000 sec is generally the max you should go. With this Tbolt, the best results can be obtained with a 'special' TC setting to 2000 to 3000. Attached is the last 2 weeks of a Lady Heather plot, showing a temperature tracking test I did to see how long it takes a Tbolt to learn a new environment. This unit has a Poor antenna, 1 sec ADEV of 1e-12, Aging of 4 e-12 / day, Temp coeff of 2.5e-10 / deg. Have fun ws > ___ 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] Achievable temperature stability for Thunderboltenvironment
On Jan 16, 2011, at 9:00 PM, Mark Sims wrote: > There is some info on implementing the temperature controller in the comments > at the start of the file heather.cpp Hi Mark, Thanks very much for the information. I wasn't actually aware that Heather was open-source. That's great as I can read the source for all the details I need. Your comments will help me move more quickly towards optimal results. I like the idea of the DC relay to control the cooling fan. Thanks for your input! Kevin ___ 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] Achievable temperature stability for Thunderboltenvironment
There is some info on implementing the temperature controller in the comments at the start of the file heather.cpp You can use something the simple single ended transistor driver that Warren described or use a DC solid state relay. The program can manipulate two of the RS-232 port control signals (one for enable and the other for heat/cool). The simplest implementation uses just the heat/cool signal for controlling the fan. Heating uses self-heating of the Tbolt. Cooling uses the fan to add room air. I use a DC solid state relay with one end driven by the heat/cool signal and the other by the enable signal. I have a current limiting resistor and a zener diode across the relay to prevent overdriving the device. The TT command sets the control temperature and enables the PID with default parameters. The KA command does an auto-tune procedure to fine tune the PID parameters. You can also individually change the PID parameters using various K commands. Once you have a set if parameters that works well, you can specify them on the command line (or in a configuration or keyboard script file) When using a fan, you should set the control temperature somewhere between the maximum room temp seen and the no-fan-on self-heating temperature of the unit in the box. And there are rumors of a list member volunteering to write a Heather manual... ___ 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] Achievable temperature stability for Thunderboltenvironment
Kevin Lady Heather has a built in software PID Temperature controller. The setpoint to the PID is done using the "TT" command, the feedback is from the Tbolt's temperature sensor and the output is a 1 sec PWM signal that comes out on pin 4 (and others?) The real problem is to try and find the doc on how to use it all. I'll leave that answer to others. ws ***** [time-nuts] Achievable temperature stability for Thunderboltenvironment? Kevin Rosenberg kevin at rosenberg.net Mon Jan 17 00:12:40 UTC 2011 On Jan 16, 2011, at 4:46 PM, WarrenS wrote: > I don't know if this low resolution picture will post correctly. > If anyone wants a high resolution view of the H/W, > or an expanded plot showing the results over a 2 week period, > I can provide them, if someone will send me the name of a site to post them > at. The photo and schematic were clear, thanks for posting! I see that you have the fan controlled by pin 4 of the RS-232. Is there a mechanism in Lady Heather to control pin 4 (DTR) based on temperature readings? Or, maybe you monitor the temperature and control pin 4 with some other monitor/control program using an output different that the RS-232 port controlled by Lady Heather? Anyway, that's a great looking temperature plot, and the implementation is nicely simple. Lots of bang for that buck! Kevin ___ 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] Achievable temperature stability for Thunderboltenvironment?
On Jan 16, 2011, at 4:46 PM, WarrenS wrote: > I don't know if this low resolution picture will post correctly. > If anyone wants a high resolution view of the H/W, > or an expanded plot showing the results over a 2 week period, > I can provide them, if someone will send me the name of a site to post them > at. The photo and schematic were clear, thanks for posting! I see that you have the fan controlled by pin 4 of the RS-232. Is there a mechanism in Lady Heather to control pin 4 (DTR) based on temperature readings? Or, maybe you monitor the temperature and control pin 4 with some other monitor/control program using an output different that the RS-232 port controlled by Lady Heather? Anyway, that's a great looking temperature plot, and the implementation is nicely simple. Lots of bang for that buck! Kevin ___ 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.
