[evlatests] Weather Station

[Steven Durand]

-------- Original Message --------
Subject: Weather Station
Date: Tue, 10 Jan 2012 10:02:47 -0700
From: Wayne Koski <wkoski at aoc.nrao.edu>
Organization: NRAO
To: evlatests at nrao.edu

During the Holiday break we lost Weather Station Data around the 
time
when we powered down the array for main power work.  It was 
found at the
time that we had lost a +5V power supply in the Weather Box 
which was
replaced.  However, this did not restore the information flow 
into the
Monitoring system.  Further troubleshooting by the DCS group kept
pointing to the CMP Computer, but it was felt that I needed to 
confirm
that thinking.

Yesterday (1/9/2012) Terry Cotter and myself went to the site in 
order
to determine if the LO/IF and M&C section of the Master Rack had 
been
affected by efforts to remove the old VLA D-Racks and unused 
sections of
the Master Rack.  I determined that the timing signal (QQ) for 
the SLC
and System Buffer was there and Weather Station Data was present 
at the
Data Tap connected to the System Buffer.  However, I had to 
replace the
Dataset EPROM in order to restore the full Weather Station Data 
flow.
At this point I looked at the Data Tap again for monitor points 
from the
Weather Station (Power Supplies/Sacred +10V) that I would 
recognized and
they were there.

For those of you who need to recall or don't know the fundamental
operation of of the old M&C system here is briefly what takes place.

The System Buffer at a time based upon QQ requests information 
from its
Datsets (Weather = Dataset 0) and stores in into a serial memory.

At a different time but also based upon QQ the SLC requests the 
stored
information from the System Buffer and echoes it back thus 
displaying on
the Data Tap.  At the same time, the SLC will transfer the 
message using
three parallel transfers into the CMP for each message.

Simply put, seeing Data Tap data means that the System Buffer to 
Dataset
link and the SLC to System Buffer link are operational.

I then tried the second SLC and still no success.

My conclusion is that the issue is either at the CMP or between 
the SLC
and CMP.

At this point, I don't know what to look for in order to move 
forward.

Finally, I have a very vague recollection that we needed for the
alternate Computer Port of the SLC to be plugged into the 
Modcomp (even
powered down) for proper signal termination for the CMP to start
operations or to maintain operations.  Remember this is vague and I
could have it wrong, but if this was stripped out then maybe 
this is it.

-wayne-
-- 
Steven J. Durand       National Radio Astronomy Observatory
Electronics Division Head.    1003 Lopezville Road
575/835-7103                 Socorro, New Mexico  87801