Control Commands

Updates:

• GN: 2013-Jan-13: Introduced new commands related to the Hittite synthesizers: FSEQ-SCRIPT;

LO1A-WRITE; LO1B-WRITE. Added subarray arguments to all FSEQ-* commands.

• GN: 2013-Jan- 16: Added a System Recovery Procedures section to this document.

The Schedule program needs to send commands and information to the Array Control Computer (ACC) in order to specify antenna pointing coordinates, tuning, and other system parameters that will change from scan to scan and for different modes of operation (e.g. calibrations of various types, normal solar observing, etc.). This document specifies a command language to accomplish this task, with commands at two levels: (1) High-level commands (macro-commands) that accomplish standard operations in a human-readable form, and will mainly be specified in the top layer of the schedule, and (2) atomic commands from which such macro-commands are constructed, that provide flexibility in defining the order and duration of discrete tasks. Examples of macro-commands would include a SOLPNTCAL command, which initiates a pointing procedure that does multiple offsets of the antennas and takes data that will be analyzed for determining frequency-dependent pointing offsets. Examples of atomic commands would be DATA-ON, which starts data recording, or DOSEQ, which initiates a tuning sequence. The schedule will contain macro-commands associated with files of the same name, e.g. the SOLPNTCAL command would be associated with a file named solpntcal.ctl, which contains a list of atomic commands to execute the SOLPNTCAL. These atomic commands are what will be executed (either locally or by sending the command on to the ACC). It is expected that the ACC will return from receiving an atomic command immediately, and if a command takes some time, the ACC will store and execute the commands in the order received. The currently running atomic command will be indicated in the stateframe, and the Schedule program will examine the stateframe to determine when an individual atomic command is completed. The stateframe will also include the macro command currently being executed. This draft document specifies that both macro- and atomic commands be given as ASCII text in UPPER CASE in the stateframe. It can be typed in lower case in the schedule, but will be converted to upper case prior to display and transfer to the ACC. Although the macro-command will be sent to the ACC, typically this is for information only (for writing into the stateframe), and the ACC will act only on the atomic commands.