Date: Fri, 7 Dec 2001 17:30:55 -1000 
From: Doug Summers <dsummers@keck.hawaii.edu>
To: "'denault@jeans.ifa.hawaii.edu'" <denault@jeans.ifa.hawaii.edu>
Subject: RE: version 1.1 of the LTCS URL interface spec

Hi Tony,

The LTCS is partitioned into two distinct unix processes.  One of these
collects the data from all telescopes on the mountain, and the other
processes the inputs through a geometric analysis (GA) model.  The collector
will see if timestamps are stale and complain, but the geometric model won't
know about this.  It continues to use whatever the last information it had.
Because of this, it's necessary to set the URL to be LASER_IMPACTED=NO at
shutdown time.  Then it doesn't matter if it's read or not, the GA will know
that the positions don't matter.  Otherwise, the collector just alarms.

Do you think this will be a big problem for us?

Also, I have some immediate feedback for the URL for you.  Here's what I see
from the sample you sent:

a.  spelling problem with "TIMESTAMPE1, TIMESTAMPE2": Need to drop the E
    It should be "TIMESTAMP1" and "TIMESTAMP2"
b.  You are the only site to use exponential formats in the URL.  I haven't 
    seen this or tested it yet (although I know it says in the spec we can
    handle it).  I'm not sure if you can convert to non-exponential format
    or not, but if it's easy, you might consider it for RA/DEC & FOV.  If
it's
    a problem to do this, I'll test it.  I just haven't yet and I'm worried
    that the Gemini code (collector) may not handle it.  If not, I'll need
to
    go into their code and adjust, but I'd rather not do that before Tuesday
    if I can help it.  Is this something you can easily change in case it
    doesn't work?
c.  While it is allowed to set the LOG_DATA flag to OFF, by agreement of the
    MKLGSTWG members, this flag should be set to ON during the initial LTCS
    software testing period.  The effect of having it off is that I will
lose
    all knowledge of where you are pointing, and we won't be able to debug
    any problems that arise as a result of the laser crossing your guider.  
    If you can change this to ON for now, that will be great.

Otherwise, looks good.

Thanks,
Doug

-----Original Message-----
From: Tony Denault [mailto:denault@jeans.ifa.hawaii.edu]
Sent: Friday, December 07, 2001 5:06 PM
To: Doug Summers
Cc: Paul Stomski; Peter Wizinowich; Alan Tokunaga
Subject: Re: version 1.1 of the LTCS URL interface spec


On Fri, 7 Dec 2001, Doug Summers wrote:

> Hi Tony,
> 
> Here's the spec we spoke about on the phone today.  As we agreed, I will
use
> a 15 second polling rate from the Collector to process collision
predictions
> from the LTCS.  Let me know when you'd like me to take a look at the
sample
> URL.  If by chance you need the IP address of the LTCS for firewall
> protection issues, the host that will be used is 128.171.136.122
> 
> Please let me know if I can assist testing, and thanks for your
> participation!
> 
> Regards,
> Doug Summers
> CARA
> W.M. Keck Telescope
> 808 331-3887 (direct)
> 
>

Hello Doug,

I had a late start at it, but the IRTF should be able to provide
TCS pointing data for the LTCS for the Dec 11 run.

Now, I have test program that updates our URL. The ra,dec position is just 
zenith as the program is not tied into our tcs yet. I hope this
would be helpful in testing the communication between the IRTF and
Keck's LTCS, and to check our formatting Here is the URL. (I am update at
about 15 seconds intervals).

http://irtf.ifa.hawaii.edu/Facility/LaserTraffic/tcs_data.txt


I was working off the the 1.0 specification. On Monday, I'll tie 
the application into our TCS. Update for the 1.1 specification (although
after a quick look, it should be OK). And fix any problems you report.

Question:

1. Our TCS is an old beast. It is booted up and started by the Telescope
Operator when night time observing begins, and shutdown at dawn. When the
tcs is OFF, and the timestamp is stale (ie: 1 minute old). What does your
system do? Does is assume LASER_IMPACT = NO, and RA,DEC are invalid?


Aloha,

Tony
 
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| Tony Denault                       | Email: denault@irtf.ifa.hawaii.edu |
| NASA IRTF, Institute for Astronomy |              Phone: (808) 933-0893 |
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