South Pole Diaries 1997/98

   

   

 

Friday 28th November - Feng Shui in the AASTO

From John Storey.....

Today began early for the welder, who used an oxy torch to cut a bigger hole in the friction-drive disc of SPIREX. I wasn't around to see this, but I never cease to be amazed at the precision with which a skilled welder can cut through 1-inch plate steel. The 300lb disc is now mounted back on SPIREX (I'm not sure if the crane was used, or if Fred just carried it up the stairs under one arm), and the holes have been drilled and tapped ready to mount Abu on it.

We now have a second ethernet cable made up inside the AASTO, so we can run both the "old super" (PC104 + brown slime) and the "new super" (ACER 386 + excruciatingly loud fan) simultaneously. The ethernet cable is a lurid shocking pink colour, and completely ruins the interior decor of the AASTO. We need a Feng Shui consultant to come in and re-balance the Ying and Yang of the structure. Maybe I'll be able to successfully telnet into the DCU once that's done.

Speaking of telnetting to the DCU, I wasted about half a day on that today. If we try to do it via port 4 of the super, the super simply hangs and has to be restarted. I supect it's a handshaking problem. I might try the "start mism" command, which sends out a character on the RS232 line willy-nilly. One doesn't like to hassle inanimate objects, but I'm going to have assert a CTS if the situation doesn't improve. RS232 is without doubt the most stupid, complicated, arbitrary, ambiguous, brain-dead, non-standard means of communication ever invented. Horowitz and Hill have tried to make the whole thing sound amusing, but in reality they should just line up averyone responsible for the RS232 mess and shoot them (including the morons who designed the original PC, and saved 25 cents per computer by going to a 9-pin D instead of a 25-pin).

The Toshiba is connected to the DCU via a cable, a gender-bender, a null modem and a 9-to-25 pin adaptor.

I also tried running Kermit on the 386 super, but with equally blank results. It's not clear, however, whether the original serial ports of that machine still work.

Ok, problem solved. Serial port four from the Moxan (alias the octopus) isn't connected to anything. The situation improves markedly if we pretend the DAU is an AFOS, and connect it to the #1 port. I can now telnet in and get the same display as is on the Toshiba. There's still a funny, though: the screen will toggle into a mode where the *lower case* letters become Egyptian hierogyphics, and I can't send any command that requires a lower case letter or a numeral. Thinking that his might be a misunderstanding between poddle and the DCU over how many bits there are in an 8-bit word, I tried telnetting in from pharlap - but got the same result. (Note: a null modem is required.)

Now, by connecting to one of the serial data IO ports on the DAU (no null modem is required), and telnetting in, one gets (in about 5 seconds):

*3524470233*4524470233*5524470233*6524470233*7524470233*8524470233*9524470233 *0624470233*1624470233*2624470233*3624470233*4624470233*5624470233*6624470233 *7624470233*8624470233*9624470233*0724470233*1724470233*2724470233*3724470233 *4724470233*5724470233*6724470233*7724470233*8724470233*9724470233*0824470233 *1824470233*2824470233*3824470233*4824470233*5824470233*6824470233*7824470233 *8824470233*9824470233*0924470233*1924470233*2924470233*3924470233*4924470233 *5924470233*6924470233*7924470233*8924470233*9924470233*0034470233*1034470233 *2034470233*3034470233*4034470233*5034470233*6034470233*7034470233*

which is just what we expect. It's the time stamp, every 0.1 seconds, in the format: 0.1s s s m m h h d d d, and seeing as how it's coming from the GPS, now's a good time to adjust my watch.

On a continuing cheerful note, it turns out that the mirror that fell off the MISM was the only one in all of our instruments that was attached with epoxy, rather than RTV. It's clear that in fact the epoxy held pretty well, but that differential thermal expansion simply tore chunks of glass out of the back of the mirror. Ant has glued a new (large rectangular) mirror back on (with RTV), and we'll leave it until tomorrow before we start the alignment. The mirror is sitting with a spool of solder on top of it to ensure it properly conacts the alignment pads. Thanks for all those tips, Max.

There's a water shortage in the Beaker Box (or Elevated Dorm, as it's sometimes referred to. Apparently the day crew only fill the snow melter up once per day, and the beakers (scientists) are using more than a tankful. A confrontation is looming. The beakers claim that non-residents of the Beaker Box are coming in and using the washing machines (because they're better than the others) and that's where the water's going. The snow-melter fillers claim the beakers are taking long showers, and foolishly suggested that the beakers should learn to drive bulldozers so they can fill the melter themselves. They were nearly knocked down by the rush of volunteers. Today, a Sprite; tomorrow a D9!

I spent the morning caefully checking the NISM, and as far as I can see it is performing faultlessly. There was a worrying moment when I found the signal varying wildly for no apparent reason, but then looked out the windows and saw clouds scudding by. ("Scudding" is an activity induldged in only by clouds and by Ant when driving the Sprite.)

Actually there is one "funny" in the nism, and that is that the noise on det and detx, as read by the ADC, is higher than it is on the cro.

Mcba: does the software just take a single sample, or does it take a burst at the peak of the waveform, or does it average over several cycles, or what?

Another software feature: when I type in "10 (adc det dlys 2)", it works most of the time but once I got:

Error #238 Can't decode loop count after the first loop. I take this to mean that the computer was incapable of counting up to 2, which, given the altitude, is entirely understandable.

The two beams of the Nism (and yes, there are two!) are particularly well balanced: with the window covered we get 2.8mV rms from the "det" output of the signal board.

I spoke over breakfast to the station doctor about the problems of dry and cracking skin. He claims that when he goes walking at high altitude he finds the best thing to take care of cracking skin is ... superglue! I'l take his word for it.

Only a couple of Herc flights today, and in fact only a few in total over the last few days. Fog at McMurdo seems to be the main culprit. They did manage to get some beer here for Thanksgiving, for which there will no doubt be many thanks given.

However, I'm told that they're very short of turkeys at McMurdo, and the environmental protection people are standing guard over the local penguins.

We had a couple of visitors to the AASTO today: a reporter and the NSF science representative. We may have to instal a visitors' gallery on the mezzanine level.

When the AASTO ceiling is +26C and the outside ambient -30C, the NISM housing is -12C. In other words, the NISM housing is only 18C above ambient but 38C below room temperature. I think we need it a lot closer to the room temperature than that. Looking at the RS cattle dog, a heatsink something like RS 271-864 represents good value in terms of watts/K/$, so how about a couple of these bolted to either face of the aluminium door to the NISM?

A few other things we need are some MAX 471 current-sense ICs (these are doing a fantastic job of protecting the fuse in series wth them), some MAX796-EV power supplies (say two), and some more of the "big" rectangular mirrors from Edmund (Ant asks - can we get them without that stupid Ed. Sci. sticker on the back that is a cow to clean off). By the way, Maxim will send you up to 5 MAX 471's for nothing if you ask them nicely via their web page. They are indeed cheaper than fuses!

Tomorrow is Thanksgiving and most people on the station will take a holiday Sat. and Sunday. Probably there won't be any flights. I've volunteered to front up at 3pm to be trained as a drinks waiter. Ant is serving at the tables. Woe betide anyone who looks like they were instrumental in the development of the RS232 standard.

John

 

 

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