Observations: EHT 2021 Redirected from 01VLBI Group/Projects/VLBI - PV Support/EHT 2021

    This page is deprecated (only valid for 2021 EHT observations).

    Prerequisits

    • Go through the system setup procedure for the DBBC3 and verify that the system is in a working condition.

    System initialization

    More detailed information can be found also on the EHT-wiki

    Module initialization

    ONLY IF REQUIRED: Initialise the modules using the following command. It has to be repeated separately for each Mark6 that has modules that need initialising (example below references the Mark6 using hostname 'recorder1').

    This command will erase all existing data on the modules.

    If you are unsure whether to initialise a set of modules, request guidance from AOC.

    backendctl mark6 recorder1 modules 1,2,3,4 init-fresh
    

    if the modules are still in "open" state they must be unmounted before

    backendctl mark6 recorder1 group unmount
    

    Repeat for all recorders

    Initialize, configure  & validate the DBBC3

    Load the OCT_D firmware

    On the DBBC3 desktop

    • close any other running control software programs
    • close the DBBC3 client program
    • double click the icon labeled "DBBC3 Control OCT_D_v110.exe"   (Version number can be different)
    • answer first question with "y" in order to do a full reload of the firmware.
    • wait until the control software has fully loaded and responds with "Waiting for connection on port 4000"

    Load the filters and validate the system

    make sure the DBBC3 client is not running

    cd /home/oper/rottmann/dbbc3/utilities
    ./setupDBBC3_OCT_D.py dbbc3 -n 4
    

    After carrying out a number of tests and verifications the script will ask whether you want to load the filters. Answer with 'y'.

    Note: any checks prior to this question will fail if the filters have already been loaded.

    All checks should report "OK".

    Check time synchronisation

    Time syncronisation can be checked with the tick command via the serial interface.

    Follow these steps below exactly. Omitting any step will lead to mal-functioning and will require to completely reload the firmware.

    On the DBBC3 desktop:

    • open the dbbc3 client program and issue:
    disableloop
    
    • double-click the putty icon
    • in putty open connection e.g. to DBBC3 Board A
    • in the window hit enter to get to the command prompt and execute:
    • tick
    • compare the timestamps to a radio-controlled clock
    • when done hit enter to stop the tick command
    • close the putty window
    • in the dbbc3 client program  issue:
    enableloop
    

    Validate the VLBI System (Except DBBC3)

    on the EHT control computer run:

    backendctl whole check
    

    This will check the setup of the control computer and the recorders. The check of the DBBC3 is not yet included in this procedure (see above).

     

    Adjust power levels (DBBC3)

    Basically low/high power levels should have been reported by setup script (see above).

    In DBBC3 client:

    check attenuators, e.g. for board A:

    dbbcifa
    

    attenuator settings should be within 20-40, agc should be on

    if reported attenuator level is out of range 20-40 the IF power must be decreased/increased.

    Do test recording

     backendctl mark6 all run test-recording 20 30 
    

    Recording starts with a delay of 20 seconds. Visually check if all recorders are actually recording.

     

    Record & plot

    log into the recorder e.g. recorder1

    ssh -Y recorder1
    

    execute:

    plotdbbc3_m6.sh
    

    This will do a short test recording and plot the resulting spectrum in both polarizations

    Load and execute the schedule

    Scedules are located under /srv/vexstore

    load the schedule that  has been triggered by the AOC:

    backendctl mark6 all schedule load trigger
    

    Follow the schedule:

     backendctl whole schedule follow trigger
    

     

    Start the Mark6 monitoring client

    copy the vex file (e.g. from /srv/vexstore/trigger) to /home/oper/shared/schedules

    vex2xml.py -f {vexfile} -s Pv
    

    check the contents of the generated {schedule}.xml if it contains scans

    m6schedulemon.py recorder1 {schedule}.xml  &
    

    repeat for all recorders you want to monitor

     

     

     

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