Re: [time-nuts] Time security query
When something goes wrong in an accelerator, like an unsolicited beam dump, the timing system broadcasts a Post Mortem event (message) and lots of equipment push diagnostics data with time tags up to the Post Mortem system for analysis. These PLCs control things like Cryogenics, and other industrial-like systems, and are very removed from what we do in the timing team. I suppose they run a simplified NTP client, because NTP is not considered critical for their mission and they don't have much memory or time to devote to this. Your proposal of using a dedicated NTP server to monitor the PLCs looks interesting, I'll look into it. Tagging PPS could be risky as you say, maybe tagging something like a 0.1 Hz pulse train would be better. We could then trigger an alarm as soon as the time tags are off by one second. On Wed, Aug 26, 2009 at 12:43 AM, Hal Murray hmur...@megapathdsl.netwrote: javier.serrano.par...@gmail.com said: There are some exceptions to this, with PLCs and other pieces of hardware getting sync from NTP. We've had problems in our Post Mortem system in the past, with a PLC not receiving NTP traffic because of router misconfiguration and this resulting in incoherent time tags. Are your PLCs running full NTP or some minimal implementation? The reference implementation has a lot of monitoring/debugging options. Probably the simplest approach is to setup a ntp server and use it to monitor the systems you are interested in. (I'll say more if anybody wants.) Speaking of software bugs, many of the minimal implementations have interesting problems. In case anybody isn't familiar with it, Dave Plonka has a wonderful writeup of the Netgear/Univ-Wisc mixup. I'd call it required reading for any computer science program. http://pages.cs.wisc.edu/~plonka/netgear-sntp/http://pages.cs.wisc.edu/%7Eplonka/netgear-sntp/ Wikipedia has a page that covers a few more incidents: http://en.wikipedia.org/wiki/NTP_server_misuse_and_abuse Anyway, if you are using ntp, add denial-of-service to the list of considerations, either on your servers or the servers you are using. For popular servers like the ones run by NIST, there are significant errors during the normal daily peak load times. Our proposed solution for that is to feed a PPS from one of our timing receivers to the critical PLCs and ask them to time-tag it with their internal NTP-derived time base. Is tagging a PPS enough? How do you know if you are off by several seconds? -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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] 58540A, anyone ?
Hi all, anyone here has an HP 54540A for sale? Answers to ik1...@spin-it.com 73 - Marco IK1ODO ___ 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] Service manual / schematics HP 5334A`
Hello everyone, Can you, please, help me with finding a service manual and schematics of the HP counter 5334A. On the Agilent site I can find the 5334B but I know there are quite some differences between both. Any info would be appreciated. Thanks, bdivi-at-hotmail.com ___ 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] Tbolt temperature Control
TBolt Nuts To keep My TBolt's temperature constant so that the environment has minimal effect on it, I use an aquarium temperature controller (modified to have low hysteresis) connected to a low wattage light bulb, placed in a box with the TBolt. It works OK and keeps the TBolt's temperature constant to well under 1 deg. To do it better and make it more hi tech, I'd like to have the temperature control based on the TBolt's internal sensor. What I have found works well is to use the TBolt's own RS232 temperature sensor output data, and with a modified PID type of S/W controller, turn an external heater /or cooler on off. The heater can be an appropriate power resistor or transistor dissipating up to about 4 Watt, mounted to the TBolt case. What I use to cool the Tbolt up to 5 deg C, is a small fan blowing at a heatsink mounted on the top of the TBolt's case. Turning the fan on off with a S/W driven switch, can be used to keep the TBolt's internal temperature very constant over a limited external temperature range. A standard PC chip fan heatsink may be OK, if it does not add Phase noise due to it's vibration. Because of the long time constant and slow response of the internal temperature sensor, a single digital on-off bit, updated at a max rate of once per second works great for control, No analog needed. To keep the hardware and interface circuit simple, I'd like to be able to use one of the unused standard RS232 outputs, such as RTS, CTS, DSR, DTR as the heater/cooler control bit(s). This is no problem when doing this in a DOS program or from an added microprocessor that monitors the Tbolt's communications, But the question is, can it be done in Windows in such a way that a modified existing program such as Lady Heather or Tbolt monitor could control an already existing readily available digital bit? Being a control person, Doing a software algorithm is the easy part. Making Windows do any kind of non standard I/O control, is way above my capability. I'd like to get feedback from a Windows expert if there is a simple way to control an existing Digital bit that would be available on a PC being used in a typical setup that is used to monitor the Tbolt. One way I have heard suggested is to use the sound card output, but I'd like to keep it even simpler than that, Any suggestions? If anyone is interested in developing a program to make an existing stand alone micro or basic stamp to include this function they can contact me off line for some sugestions. Thanks, 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] Tbolt temperature Control
Heck, Warren, I'll put it on the line :-). Use a very simple and cheap processor such as a Picaxe, pass the rs232 through it to Lady Heather etc, and capture the temperature, using it appropriately. Should work nicely and keeps the temp control local. Even put a little LED on it to indicate state. Don WarrenS TBolt Nuts To keep My TBolt's temperature constant so that the environment has minimal effect on it, I use an aquarium temperature controller (modified to have low hysteresis) connected to a low wattage light bulb, placed in a box with the TBolt. It works OK and keeps the TBolt's temperature constant to well under 1 deg. To do it better and make it more hi tech, I'd like to have the temperature control based on the TBolt's internal sensor. What I have found works well is to use the TBolt's own RS232 temperature sensor output data, and with a modified PID type of S/W controller, turn an external heater /or cooler on off. The heater can be an appropriate power resistor or transistor dissipating up to about 4 Watt, mounted to the TBolt case. What I use to cool the Tbolt up to 5 deg C, is a small fan blowing at a heatsink mounted on the top of the TBolt's case. Turning the fan on off with a S/W driven switch, can be used to keep the TBolt's internal temperature very constant over a limited external temperature range. A standard PC chip fan heatsink may be OK, if it does not add Phase noise due to it's vibration. Because of the long time constant and slow response of the internal temperature sensor, a single digital on-off bit, updated at a max rate of once per second works great for control, No analog needed. To keep the hardware and interface circuit simple, I'd like to be able to use one of the unused standard RS232 outputs, such as RTS, CTS, DSR, DTR as the heater/cooler control bit(s). This is no problem when doing this in a DOS program or from an added microprocessor that monitors the Tbolt's communications, But the question is, can it be done in Windows in such a way that a modified existing program such as Lady Heather or Tbolt monitor could control an already existing readily available digital bit? Being a control person, Doing a software algorithm is the easy part. Making Windows do any kind of non standard I/O control, is way above my capability. I'd like to get feedback from a Windows expert if there is a simple way to control an existing Digital bit that would be available on a PC being used in a typical setup that is used to monitor the Tbolt. One way I have heard suggested is to use the sound card output, but I'd like to keep it even simpler than that, Any suggestions? If anyone is interested in developing a program to make an existing stand alone micro or basic stamp to include this function they can contact me off line for some sugestions. Thanks, 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. -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ 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] Tbolt temperature Control
Note you do not have to pass anything thru or output any RS232, just the ONE bit if the micro is going to control the temp out bit. It just needs to pick up the Tbolt output data in parallel and capture the Temp info. If the micro is not doing the Temp control then there is no need to have the extra micro. ws Don Latham said: Heck, Warren, I'll put it on the line :-). Use a very simple and cheap processor such as a Picaxe, pass the rs232 through it to Lady Heather etc, and capture the temperature, using it appropriately. Should work nicely and keeps the temp control local. Even put a little LED on it to indicate state. Don WarrenS TBolt Nuts To keep My TBolt's temperature constant so that the environment has minimal effect on it, I use an aquarium temperature controller (modified to have low hysteresis) connected to a low wattage light bulb, placed in a box with the TBolt. It works OK and keeps the TBolt's temperature constant to well under 1 deg. To do it better and make it more hi tech, I'd like to have the temperature control based on the TBolt's internal sensor. What I have found works well is to use the TBolt's own RS232 temperature sensor output data, and with a modified PID type of S/W controller, turn an external heater /or cooler on off. The heater can be an appropriate power resistor or transistor dissipating up to about 4 Watt, mounted to the TBolt case. What I use to cool the Tbolt up to 5 deg C, is a small fan blowing at a heatsink mounted on the top of the TBolt's case. Turning the fan on off with a S/W driven switch, can be used to keep the TBolt's internal temperature very constant over a limited external temperature range. A standard PC chip fan heatsink may be OK, if it does not add Phase noise due to it's vibration. Because of the long time constant and slow response of the internal temperature sensor, a single digital on-off bit, updated at a max rate of once per second works great for control, No analog needed. To keep the hardware and interface circuit simple, I'd like to be able to use one of the unused standard RS232 outputs, such as RTS, CTS, DSR, DTR as the heater/cooler control bit(s). This is no problem when doing this in a DOS program or from an added microprocessor that monitors the Tbolt's communications, But the question is, can it be done in Windows in such a way that a modified existing program such as Lady Heather or Tbolt monitor could control an already existing readily available digital bit? Being a control person, Doing a software algorithm is the easy part. Making Windows do any kind of non standard I/O control, is way above my capability. I'd like to get feedback from a Windows expert if there is a simple way to control an existing Digital bit that would be available on a PC being used in a typical setup that is used to monitor the Tbolt. One way I have heard suggested is to use the sound card output, but I'd like to keep it even simpler than that, Any suggestions? If anyone is interested in developing a program to make an existing stand alone micro or basic stamp to include this function they can contact me off line for some sugestions. Thanks, 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] Tbolt temperature Control
Another useful feature to add to a completely independent micro controller so that it needs no other inputs is to have its program smart enough to automatically and slowly readjust its set point control Temperature to just above the highest day to day Peak temp it sees. Needs no extra inputs, It just needs to monitor its own PID loop to see if it even comes out of control due to excess temp. warren Wrote: Note you do not have to pass anything thru or output any RS232, just the ONE bit if the micro is going to control the temp out bit. It just needs to pick up the Tbolt output data in parallel and capture the Temp info. If the micro is not doing the Temp control then there is no need to have the extra micro. ws Don Latham djl at montana.com Wed Aug 26 17:38:21 UTC 2009 a.. Previous message: [time-nuts] Tbolt temperature Control b.. Next message: [time-nuts] Tbolt temperature Control c.. Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Heck, Warren, I'll put it on the line :-). Use a very simple and cheap processor such as a Picaxe, pass the rs232 through it to Lady Heather etc, and capture the temperature, using it appropriately. Should work nicely and keeps the temp control local. Even put a little LED on it to indicate state. Don WarrenS TBolt Nuts To keep My TBolt's temperature constant so that the environment has minimal effect on it, I use an aquarium temperature controller (modified to have low hysteresis) connected to a low wattage light bulb, placed in a box with the TBolt. It works OK and keeps the TBolt's temperature constant to well under 1 deg. To do it better and make it more hi tech, I'd like to have the temperature control based on the TBolt's internal sensor. What I have found works well is to use the TBolt's own RS232 temperature sensor output data, and with a modified PID type of S/W controller, turn an external heater /or cooler on off. The heater can be an appropriate power resistor or transistor dissipating up to about 4 Watt, mounted to the TBolt case. What I use to cool the Tbolt up to 5 deg C, is a small fan blowing at a heatsink mounted on the top of the TBolt's case. Turning the fan on off with a S/W driven switch, can be used to keep the TBolt's internal temperature very constant over a limited external temperature range. A standard PC chip fan heatsink may be OK, if it does not add Phase noise due to it's vibration. Because of the long time constant and slow response of the internal temperature sensor, a single digital on-off bit, updated at a max rate of once per second works great for control, No analog needed. To keep the hardware and interface circuit simple, I'd like to be able to use one of the unused standard RS232 outputs, such as RTS, CTS, DSR, DTR as the heater/cooler control bit(s). This is no problem when doing this in a DOS program or from an added microprocessor that monitors the Tbolt's communications, But the question is, can it be done in Windows in such a way that a modified existing program such as Lady Heather or Tbolt monitor could control an already existing readily available digital bit? Being a control person, Doing a software algorithm is the easy part. Making Windows do any kind of non standard I/O control, is way above my capability. I'd like to get feedback from a Windows expert if there is a simple way to control an existing Digital bit that would be available on a PC being used in a typical setup that is used to monitor the Tbolt. One way I have heard suggested is to use the sound card output, but I'd like to keep it even simpler than that, Any suggestions? If anyone is interested in developing a program to make an existing stand alone micro or basic stamp to include this function they can contact me off line for some sugestions. Thanks, ws ** ___ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ 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] Tbolt temperature Control
This can also be made to work on the TBolt units that have the 1/2 deg course Temp sensor. The control loop gets a bit trickier, but it can hold the Temp very close at one its course transitions points. This would come in handy for those not wanting to change their sensor to the high resolution type. Another useful feature to add to a completely independent micro controller so that it needs no other inputs is to have its program smart enough to automatically and slowly readjust its set point control Temperature to just above the highest day to day Peak temp it sees. Needs no extra inputs, It just needs to monitor its own PID loop to see if it even comes out of control due to excess temp. Note you do not have to pass anything thru or output any RS232, just the ONE bit if the micro is going to control the temp out bit. It just needs to pick up the Tbolt output data in parallel and capture the Temp info. If the micro is not doing the Temp control then there is no need to have the extra micro. ws Don Latham djl at montana.com Wed Aug 26 17:38:21 UTC 2009 Heck, Warren, I'll put it on the line :-). Use a very simple and cheap processor such as a Picaxe, pass the rs232 through it to Lady Heather etc, and capture the temperature, using it appropriately. Should work nicely and keeps the temp control local. Even put a little LED on it to indicate state. Don ** TBolt Nuts To keep My TBolt's temperature constant so that the environment has minimal effect on it, I use an aquarium temperature controller (modified to have low hysteresis) connected to a low wattage light bulb, placed in a box with the TBolt. It works OK and keeps the TBolt's temperature constant to well under 1 deg. To do it better and make it more hi tech, I'd like to have the temperature control based on the TBolt's internal sensor. What I have found works well is to use the TBolt's own RS232 temperature sensor output data, and with a modified PID type of S/W controller, turn an external heater /or cooler on off. The heater can be an appropriate power resistor or transistor dissipating up to about 4 Watt, mounted to the TBolt case. What I use to cool the Tbolt up to 5 deg C, is a small fan blowing at a heatsink mounted on the top of the TBolt's case. Turning the fan on off with a S/W driven switch, can be used to keep the TBolt's internal temperature very constant over a limited external temperature range. A standard PC chip fan heatsink may be OK, if it does not add Phase noise due to it's vibration. Because of the long time constant and slow response of the internal temperature sensor, a single digital on-off bit, updated at a max rate of once per second works great for control, No analog needed. To keep the hardware and interface circuit simple, I'd like to be able to use one of the unused standard RS232 outputs, such as RTS, CTS, DSR, DTR as the heater/cooler control bit(s). This is no problem when doing this in a DOS program or from an added microprocessor that monitors the Tbolt's communications, But the question is, can it be done in Windows in such a way that a modified existing program such as Lady Heather or Tbolt monitor could control an already existing readily available digital bit? Being a control person, Doing a software algorithm is the easy part. Making Windows do any kind of non standard I/O control, is way above my capability. I'd like to get feedback from a Windows expert if there is a simple way to control an existing Digital bit that would be available on a PC being used in a typical setup that is used to monitor the Tbolt. One way I have heard suggested is to use the sound card output, but I'd like to keep it even simpler than that, Any suggestions? If anyone is interested in developing a program to make an existing stand alone micro or basic stamp to include this function they can contact me off line for some sugestions. Thanks, 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.
[time-nuts] Couple of questions for Racal 1992 owners
Just acquired a used 1992 off eBay. Excellent, almost like new with manual and even spare fuses. I noticed that the internal reference's waveform is more like a nasty sawtooth than a nice sine wave. Is that normal? Also, when I hook my GPSDO through a two way splitter and two different length cables and measure phase, I get a +\- 3 LSD ambiguity. Is that about right? ___ 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] Tbolt temperature Control
Putting the PID stuff into Lady Heather is no problem (if you write the algorithm). It would be pretty trivial to drop it into the DOS version. It would be best if a single control line would either heat or cool (no OFF state). Even simpler, keep the fan stirring the air all the time. Apply heat when needed. The problem is with the Windows code. I don't know how to reliably control the modem signals under Windows... perhaps John Miles would know. Most Windows users use USB-RS232 converters and these are infamous for their flakey control signals. I think the most reliable way would be a small micro that monitored the TSIP strings from the Tbolt and picked off the message that has the temperature field. Ideally a Peltier device driven by an H bridge motor controller would control the heating and cooling. By insulating the Tbolt in a foil covered cardboard box, you should be able to keep the a/c and heating induced temperature swings under 0.1C. It is these short term swings that the Tbolt seems most sensitive to. _ Hotmail® is up to 70% faster. Now good news travels really fast. http://windowslive.com/online/hotmail?ocid=PID23391::T:WLMTAGL:ON:WL:en-US:WM_HYGN_faster:082009 ___ 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] Tbolt temperature Control
-Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims Sent: Wednesday, August 26, 2009 1:35 PM To: time-nuts@febo.com Subject: [time-nuts] Tbolt temperature Control Putting the PID stuff into Lady Heather is no problem (if you write the algorithm). It would be pretty trivial to drop it into the DOS version. It would be best if a single control line would either heat or cool (no OFF state). Even simpler, keep the fan stirring the air all the time. Apply heat when needed. The problem is with the Windows code. I don't know how to reliably control the modem signals under Windows... perhaps John Miles would know. Most Windows users use USB-RS232 converters and these are infamous for their flakey control signals. Which Windows? Or more properly, which flavor of .NET? I've had fairly good luck with the later .NET incarnations (=2) even with USB/Serial dongles. ___ 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] Tbolt temperature Control
At 03:34 PM 8/26/2009 , Mark Sims wrote: The problem is with the Windows code. I don't know how to reliably control the modem signals under Windows... perhaps John Miles would know. Most Windows users use USB- EscapeCommFunction()? ___ 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] Tbolt temperature Control
I use the System.IO.Ports.SerialPort.RtsEnable property If you're doing input (e.g. looking for a 1pps), I would imagine you'd use the PinChangedEvent. I haven't tried it or looked at the timing. These exist in all .NET frameworks from 2.0 onwards. If you want to use the Windows API directly, EscapeCommFunction(hFile,SETRTS) would presumably work. James Lux, P.E. Task Manager, SOMD Software Defined Radios Flight Communications Systems Section Jet Propulsion Laboratory 4800 Oak Grove Drive, Mail Stop 161-213 Pasadena, CA, 91109 +1(818)354-2075 phone +1(818)393-6875 fax -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Scott Newell Sent: Wednesday, August 26, 2009 1:48 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Tbolt temperature Control At 03:34 PM 8/26/2009 , Mark Sims wrote: The problem is with the Windows code. I don't know how to reliably control the modem signals under Windows... perhaps John Miles would know. Most Windows users use USB- EscapeCommFunction()? ___ 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] Couple of questions for Racal 1992 owners
My 1992 has a similarly ugly reference output - until I terminate it. Then it's a fairly nice square wave between 0 and 1 volt. Rise fall times are in the range of 5 ns. The manual doesn't state what the wave shape is, only that it's 600 mVp-p into 50 ohms. I have a brochure that says TTL levels giving approx. 1Vp-p into 50 ohms. My phase measurements also have a similar amount of 'noise' to yours. Which timebase does yours have? I've got option 4E (similar to 4B). Although the timebase appears to be stable, I've noticed that the counter drifts about 5e-9 during warmup, even when the oscillator has been on standby for many days. It takes a couple of hours to settle down. Does yours do anything similar? Ed John Green wrote: Just acquired a used 1992 off eBay. Excellent, almost like new with manual and even spare fuses. I noticed that the internal reference's waveform is more like a nasty sawtooth than a nice sine wave. Is that normal? Also, when I hook my GPSDO through a two way splitter and two different length cables and measure phase, I get a +\- 3 LSD ambiguity. Is that about right? ___ 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] Tbolt temperature Control
Hi, your problem should be to adjust to physical reality, then you may be able to control you TBOLT temperature. I cannot remember the term in a PID equation that accounts for time delay. In fact there is not one! It is the wrong algorithm for controlling almost any heater! It is excellent for driving pens in pen recorders where mass, velocity and position are the terms. Thermal control must face some nasty delay functions, like Gauss's error function. When the temperature error signal is delayed, as in the TBOLT, your best control algorithm uses the inverse transfer function of the thermal system to predict a somewhat tardy response. An alternative method that works very well is to create an isothermal wall around the TBOLT which is held at constant temperature. I would suggest your light bulb and a small computer fan to create a local tornado of air around the TBOLT and by controlling the air temperature you will control the entire case of the TBOLT. This will have much faster response and may control the case of the OCXO, voltage regulators and not just the temperature sensors. There, I have had my 2c worth, cheers, Neville Michie On 27/08/2009, at 5:56 AM, WarrenS wrote: This can also be made to work on the TBolt units that have the 1/2 deg course Temp sensor. The control loop gets a bit trickier, but it can hold the Temp very close at one its course transitions points. This would come in handy for those not wanting to change their sensor to the high resolution type. Another useful feature to add to a completely independent micro controller so that it needs no other inputs is to have its program smart enough to automatically and slowly readjust its set point control Temperature to just above the highest day to day Peak temp it sees. Needs no extra inputs, It just needs to monitor its own PID loop to see if it even comes out of control due to excess temp. Note you do not have to pass anything thru or output any RS232, just the ONE bit if the micro is going to control the temp out bit. It just needs to pick up the Tbolt output data in parallel and capture the Temp info. If the micro is not doing the Temp control then there is no need to have the extra micro. ws Don Latham djl at montana.com Wed Aug 26 17:38:21 UTC 2009 Heck, Warren, I'll put it on the line :-). Use a very simple and cheap processor such as a Picaxe, pass the rs232 through it to Lady Heather etc, and capture the temperature, using it appropriately. Should work nicely and keeps the temp control local. Even put a little LED on it to indicate state. Don ** TBolt Nuts To keep My TBolt's temperature constant so that the environment has minimal effect on it, I use an aquarium temperature controller (modified to have low hysteresis) connected to a low wattage light bulb, placed in a box with the TBolt. It works OK and keeps the TBolt's temperature constant to well under 1 deg. To do it better and make it more hi tech, I'd like to have the temperature control based on the TBolt's internal sensor. What I have found works well is to use the TBolt's own RS232 temperature sensor output data, and with a modified PID type of S/W controller, turn an external heater /or cooler on off. The heater can be an appropriate power resistor or transistor dissipating up to about 4 Watt, mounted to the TBolt case. What I use to cool the Tbolt up to 5 deg C, is a small fan blowing at a heatsink mounted on the top of the TBolt's case. Turning the fan on off with a S/W driven switch, can be used to keep the TBolt's internal temperature very constant over a limited external temperature range. A standard PC chip fan heatsink may be OK, if it does not add Phase noise due to it's vibration. Because of the long time constant and slow response of the internal temperature sensor, a single digital on-off bit, updated at a max rate of once per second works great for control, No analog needed. To keep the hardware and interface circuit simple, I'd like to be able to use one of the unused standard RS232 outputs, such as RTS, CTS, DSR, DTR as the heater/cooler control bit(s). This is no problem when doing this in a DOS program or from an added microprocessor that monitors the Tbolt's communications, But the question is, can it be done in Windows in such a way that a modified existing program such as Lady Heather or Tbolt monitor could control an already existing readily available digital bit? Being a control person, Doing a software algorithm is the easy part. Making Windows do any kind of non standard I/O control, is way above my capability. I'd like to get feedback from a Windows expert if there is a simple way to control an existing Digital bit that would be available on a PC being used in a typical setup that is used to monitor the Tbolt. One way I have heard suggested is to use the sound card output, but I'd like to keep it
Re: [time-nuts] Tbolt temperature Control
Neville My responses to your well stated and mostly accurate 2c worth, even though much of it does not apply to this situation. I cannot remember the term in a PID equation that accounts for time delay. Yea, pretty hard to remember, It called Delay on Smith predictor type of PID. Sounds like you also missed where I wrote with a MODIFIED PID TYPE of S/W controller. Thermal control must face some nasty delay functions Turns out for this application, a pretty basic type of PID works very well because the sensor has very high resolution and low noise, perfect for a large derivative term and the main temp TC is very slow and very dominate. No true delay going on just some slower faster Time constants that don't effect much. It is the wrong algorithm for controlling almost any heater! Probable get some disagreement from any OXCO manufacture on that. It is excellent for driving pens in pen recorders where mass, ... In fact a basic PID is not excellent for controlling much of anything, there are much better ways, BUT It can be adjusted to drive just about anything, which is one reason it is used so much. I would suggest controlling the air temperature around the case. I agree that is the standard way and would work fine. However there are many advantages to heating the case and using the internal sensor instead. Some of which are Lower power, faster warm-up, less parts, it gets rid of that BIG delay TC you were referring to, does not need a fan, does not need a box, etc, etc. One of the things that makes the internal sensor control work so well is its better than 0.001 deg resolution. by controlling the air temperature you will control the entire case of the TBOLT. Not necessary so unless until you add your 'local tornado of air Don't need that with the case heater. (controlling air temp) will have much faster response You may want to re-think the way you said that statement because it is VERY wrong. Air controls the case of the OCXO, voltage regulators and not just the temperature sensors. In some situations controlling the internal temp sensor instead of air or case temp will work better. In this case it does not matter much, either are plenty good enough. EXCEPT if the low resolution sensor is in the Tbolt like in all the new ones, in which case its better to keep the sensor constant so that 'Bad stuff' does nopt happen when it takes it giant steps. your best control algorithm uses the inverse transfer function of the thermal system to predict a somewhat tardy response. If you want simple and 'good enough', a simple PD works fine here. Bottom line You should try it, It's easy top assemble and works good. If you need any help or have any problems with it let me know. There, I have had my 2c worth, cheers, Neville Michie Thanks, and Now I have had my 2c also, and double cheers to you Have fun, ws Neville Michie namic...@gmail.com Hi, your problem should be to adjust to physical reality, then you may be able to control you TBOLT temperature. I cannot remember the term in a PID equation that accounts for time delay. In fact there is not one! It is the wrong algorithm for controlling almost any heater! It is excellent for driving pens in pen recorders where mass, velocity and position are the terms. Thermal control must face some nasty delay functions, like Gauss's error function. When the temperature error signal is delayed, as in the TBOLT, your best control algorithm uses the inverse transfer function of the thermal system to predict a somewhat tardy response. An alternative method that works very well is to create an isothermal wall around the TBOLT which is held at constant temperature. I would suggest your light bulb and a small computer fan to create a local tornado of air around the TBOLT and by controlling the air temperature you will control the entire case of the TBOLT. This will have much faster response and may control the case of the OCXO, voltage regulators and not just the temperature sensors. There, I have had my 2c worth, cheers, Neville Michie On 27/08/2009, at 5:56 AM, WarrenS wrote: This can also be made to work on the TBolt units that have the 1/2 deg course Temp sensor. The control loop gets a bit trickier, but it can hold the Temp very close at one its course transitions points. This would come in handy for those not wanting to change their sensor to the high resolution type. Another useful feature to add to a completely independent micro controller so that it needs no other inputs is to have its program smart enough to automatically and slowly readjust its set point control Temperature to just above the highest day to day Peak temp it sees. Needs no extra inputs, It just needs to monitor its own PID loop to see if it even comes out of control due to excess temp. Note you do not have to pass anything thru or output any
