[time-nuts] Telecom Solutions DCD Cesium

Magnus Danielson cfmd at bredband.net
Sun Mar 19 05:31:11 EST 2006

From: "Robert Lutwak" <Lutwak at Alum.mit.edu>
Subject: Re: [time-nuts] Telecom Solutions DCD Cesium
Date: Sat, 18 Mar 2006 07:47:18 -0500
Message-ID: <000501c64a8a$17b46b40$ca1b10ac at lutwakhome>

> One more thing...
> Some of the older 5045 modules had badly implemented hardware handshaking on 
> the RS-232.  Sometimes it helps to wire RTS to CTS in the connector of your 
> RS232 cable which attaches to the cesium module.  In any case, it never 
> hurts.

Well, now I run a Rx & Tx null-modem cable and operate the Monitor program at
2400 baud and that did the trick. It identifies itself as
Symmetricom model 4201A S/N 2116 and the S/N matches what the unit says.

It starts of with alarm 16, then tosses alarm 03 and then alarm 05.

Looking in the 4065c manual (page 48) this means:

16: Unit restart
03: Voltage difference (Zeeman pedestal) > 160 mV
05: C-field current < 17 mA or > 20 mA

The first one is natural when just powered on/cycled.

The next one it reads numbers like 220 mV (the highest I recall, but I was not
paying attention to that number this round, so I will monitor it more closely).

Then, it raises the C-field current to lower the Rabi error, but before the
Rabi error goes below 160 mV the C-field goes out of range and I have both
03 and 05 alarms.

So, something is slightly out of tune here...

It is high time for me to understand the nitty gritty of cesium beams and this
units and its relatives in particular. I'm not quite sure exactly what all the
measures actually means and what to read out of them. Service manuals, patents,
articles and practical hints is welcome. If there is any tune-up that I can do
to resolve the issue, I would like to know. I want to get this unit into
working order.


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