The Tasks, Commands and Programs

The software is organised in three basic layers :

• Real-time tasks that monitor the antenna, receivers, or backend parameters. Among these are:

  • flag1s: this task run every second, and synchronizes all programs.

  • interp: this task interacts with the antenna control microprocessors every second.

  • astrj: task does the astronomical computations to prepare the input to the antennas. It is activated every hour and also every time a new source is requested.
  • looplo1: this task run every 10 seconds, and checks the status of the phase locks.

• Two tasks related to the correlator/fringe processing:

  • correl and correl_spectra : theses tasks control the correlators data acquisition, continuum detector, phasemeter and LO fringe rate.

• Control and display tasks, and high level control and data acquisition programs.

  • OBS : High level observing program, with integrated observing procedures. Only one occurence of OBS can run at a time.

  • RDI : interferometric data acquisition program. It is launched automatically by OBS

  • AFF: Display real-time amplitudes and phases, control alarms, etc... One copy is launched by OBS , but other copies can be run on other terminals.
  • STSA : this program is used to display the antenna positions in real-time.
  • STSH : this program is used to display the antenna deicing status and power control.

The OBS program is intended to provide complete normal operation of the instrument. However, OBS assumes it has complete control over the system. Using other commands (e.g. coo) while OBS is running may conflict with this assumption, and therefore should be avoided if possible.

The acquisition program RDI write the data on specified files, and also take care of several log files used for bookkeeping. All real-time tasks interact through global commons and a set of event flags that are used for synchronisation. More details on commons and flags are described in the ``Trouble Shooting Guide''