From: "Robert Lutwak" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Telecom Solutions DCD Cesium Date: Sun, 19 Mar 2006 07:34:43 -0500 Message-ID: <[EMAIL PROTECTED]>
Hi Robert, > Monitor3 will periodically poll and save the status data to disk for you. > See the File->Unit Monitoring Panel. It also has some very cool > plotting/analysis features (try View->Plot). You can learn a lot about your > unit by watching the dynamics of the boot sequence. Grab the data to disk > with Monitor3 and go back and look at the plots. Yes, I have alot of fancy data comming out of it thanks to Monitor3 ;O) > The old modules were 5045, which was later renamed 4201A. Some of the last > modules (maybe >2004) were named 4201B and had a new CsIII-based servo > board. Also, if you get a 4201A serviced, depending on the failure, they > may upgrade the servo to a 4201B servo board. Monitor3 can tell them apart. > Also the servo boards have different part numbers and the new one (4201B) > has a big Xilinx CPLD hanging off the microprocessor. OK. I've got a 4201A, which is logical considering when it was manufactured. > I'm not sure how much of Monitor3 will work with your older unit. I wrote > it to work with the new CsIII-based units and later went back and cobbled in > support for the old 5045/4201A instruments for the guys in technical > service. It seems to make sense (to the best of my knowledge, which I grant is limited so far). However, the log feature does not work. Maybe that is one of the differing aspects? > The telemetry was originally designed to work with a dedicated > stand-alone Sercel terminal (which has been obsolete for at least 15 years). > The old Monitor program (which you may be able to find out there somewhere > in cyberspace) only ran in a terminal emulator which only ran on native DOS > machines, i.e. it wouldn't run in a DOS window under Windows, because it did > low-level serial port control. Well, looking at the format as I read it in the 4065 manual, I should have no major problem writing myself a little program and parse it properly to work on my Linux system. I don't have a Windows box except my (well, actually my employers) laptop which I for obvious can't lock up for my time/frequency rig at home. > I think Monitor3's serial port control functions should work with your 5045, > so if you get tired of 2400 baud, you should be able to crank it up to 9600 > from the System->RS232 menu. Ah, I'll attempt that! ;O) > In order to get the 03 alarm, you must have made it through all of the > earlier boot sequence, so you must have plenty of signal level, good > microwaves, etc. That sounds re-assuring. Yes, I have assumed this too. It has acheived lock for some shorter times. > Without more information I would guess that your unit > either: > a) Problem in C-field control circuit such that DAC is demanding more > current but atoms don't seem to respond. > b) Short in one (or more) of the coils inside the tube so that current > control gets to limit without locking > c) Tube has become magnetized so the Zeeman line asymmetry is big enough > that it tries to lock on the wrong peak. OK. > Watch the "Zeeman Signal Level" during boot (before it throws the alarm). > It should be about the same as the "Clock Signal Level." If it's much lower > (in the neighborhood of zero), than you've got no C-Field in the tube, > either the supply is failed or the coils are shorted out (badly). The C-field current starts of at 18 ma when it locks, then it kicks in the 05 alarm, starts regulating and finally the 03 alarm kicks in. > If you have Zeeman Signal, next watch the "Zeeman Rabi Innovation" during > boot. After the clock's done initializing the clock and gain servos, it'll > try to acquire lock on Rabi Zeeman. You should see this number start > relatively high (maybe a couple of hundred either +/-) and then you should > see the "C-field current" and the "current-control voltage" change as Zeeman > Rabi is driven to zero. If this succeeds, than all of your electronics (and > most of your tube) is working fine. OK. > Once it acquires lock on Zeeman Rabi, it'll try to hone in on "Zeeman > Ramsey." You'll see the Zeeman Ramsey error suddenly appear (at probably > +/- 500 or so). Then the C-field current will keep changing to try to drive > this one to zero. If all is well, this is the final step of lock. If the > tube is magnetized, enough that you try to lock to the wrong Zeeman Ramsey > peak, you will see the Zeeman Rabi Innovation start to creep back upwards as > you hone in on (the wrong) Zeeman Ramsey. In this state, it will eventually > kick out an 03 alarm, and possibly an 05 as well. This is typically caused > by exposure to high magnetic fields and is fixed by degaussing the tube. I think this is pretty exactly my problem. So, I need to degaussing the tube then, how would you recommend me to do that? It seems pretty DIY-capable. ;O) I will check the boot sequence like you described. > By the way, we just finished re-writing the manuals for the CsIII and > Cs4000. The new manuals include a new Theory-of-Operation section (by me), > which you may find useful. It's not the same electronics as your 5045, but > the physics and the CBT are the same. You can get the manuals off the symm > WWW site. Great to hear. I just pulled the 4065, CsIII and Cs4000 manuals so I got that description. The one thing I missed in the 4065 manual was the description of which alarms kick in when (so the mapping described problem <-> alarm was not obvious). It is clearer with the CsIII manual. Cheers, Magnus _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
