Re: PCFS - please, please, please. (From Simon Ellingsen)
- Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ] [ by messages with attachments ]
From: <Chris.Phillips_at_email.protected>
Date: Thu, 15 Jun 2006 11:05:45 +1000 (EST)
Simon,
Effort is being made already. Mopra antenna control works but is not well
tested. Parkes antenna control should be straight forward.
>The executive summary (for those without the time to read a long
>email) - it will make our operations more reliable and for a small
>effort it will dramatically improve our user support (and bring us
>into the 1990s).
I agree we should go in this direction, but doubt it will improve
reliability. The ATNF antennas have very few problems if any related to
not using the pcfs. I agree it may improve issues such as Tsys logging
etc.
>modify the antcn.c stub program in the PCFS. If this can't be done at
>the ATCA, why not, the control systems have just been rewritten and
>this is a piece of basic functionality?
Its just software right. This is unrealistic. Euan is aware of my request
to be able to control caobs "remotely" rather than from a script. He has
grand plans of having a caobs server and a front end - we could use the
pcfs as our front end. Don't hold your breath as this is a lot of effort.
Basically for Parkes and Mopra the situation is as follows:
We have antcn controlling antenna "pointing". This seems to work well but
has minimal testing. Access is a real problem due to scheduling issues and
the time to get there. Also time to actually do the testing given all the
other (more important) things to get working. This has been done in a way
that it should be trivially to port to Parkes.
This is *not* enough though. There is also Tsys and frequency setup.
Currently frequency setup (when bug free!) just works - it would be a real
step backwards to have to set LOs by hand which. The problem here is that
the pcfs is not designed for VLBI is it designed for geodesy. They have a
totally different concept of how LO chains are setup and so far I cannot
figure out a way to get the correct sky frequency from
vex->drudg->snap->telescope. (drudg deals with LO frequencies not sky
frequencies). I have no idea if it is easy or hard to control frequency via
the pcfs for Parkes.
To go to the new pcfs we also need to either port Simon DAS controller to
a 2.4/2.6 kernel or use Jonathon Quick's DAS control code. Jon's stuff
works well but there is still an outstanding problem (possible with my
understanding) with inverted bandpasses (Jon: I have not forgotten about
this and will contact you when I have some more time to look at this).
I have spoken to Ed Himwich about Tsys logging and he felt it was not so
trivially to cope with continuous Tsys such as all ATNF antenna use. Again
this is because pcfs is not designed with astronomy in mind.
Cheers
Chris
Received on 2006-06-15 11:06:10
Date: Thu, 15 Jun 2006 11:05:45 +1000 (EST)
Simon,
Effort is being made already. Mopra antenna control works but is not well
tested. Parkes antenna control should be straight forward.
>The executive summary (for those without the time to read a long
>email) - it will make our operations more reliable and for a small
>effort it will dramatically improve our user support (and bring us
>into the 1990s).
I agree we should go in this direction, but doubt it will improve
reliability. The ATNF antennas have very few problems if any related to
not using the pcfs. I agree it may improve issues such as Tsys logging
etc.
>modify the antcn.c stub program in the PCFS. If this can't be done at
>the ATCA, why not, the control systems have just been rewritten and
>this is a piece of basic functionality?
Its just software right. This is unrealistic. Euan is aware of my request
to be able to control caobs "remotely" rather than from a script. He has
grand plans of having a caobs server and a front end - we could use the
pcfs as our front end. Don't hold your breath as this is a lot of effort.
Basically for Parkes and Mopra the situation is as follows:
We have antcn controlling antenna "pointing". This seems to work well but
has minimal testing. Access is a real problem due to scheduling issues and
the time to get there. Also time to actually do the testing given all the
other (more important) things to get working. This has been done in a way
that it should be trivially to port to Parkes.
This is *not* enough though. There is also Tsys and frequency setup.
Currently frequency setup (when bug free!) just works - it would be a real
step backwards to have to set LOs by hand which. The problem here is that
the pcfs is not designed for VLBI is it designed for geodesy. They have a
totally different concept of how LO chains are setup and so far I cannot
figure out a way to get the correct sky frequency from
vex->drudg->snap->telescope. (drudg deals with LO frequencies not sky
frequencies). I have no idea if it is easy or hard to control frequency via
the pcfs for Parkes.
To go to the new pcfs we also need to either port Simon DAS controller to
a 2.4/2.6 kernel or use Jonathon Quick's DAS control code. Jon's stuff
works well but there is still an outstanding problem (possible with my
understanding) with inverted bandpasses (Jon: I have not forgotten about
this and will contact you when I have some more time to look at this).
I have spoken to Ed Himwich about Tsys logging and he felt it was not so
trivially to cope with continuous Tsys such as all ATNF antenna use. Again
this is because pcfs is not designed with astronomy in mind.
Cheers
Chris
Received on 2006-06-15 11:06:10