CAOBS Commands

Enter the following commands only into CAOBS. All words that make up commands can be abbreviated to the first four characters. CAOBS commands (like all other AT online commands) are not case sensitive. Do not type the square brackets that surround options shown below when entering the command. The letters n and m are used to indicate numbers. For example, in ca0n, replace n with 1 - 6 to select an antenna.

attach ca0n$\vert$all

Connect CAOBS to either antenna n or all antennas. (This will be impossible if the ACC is dead or otherwise unavailable.) Use this command to try to reconnect antennas that CAOBS reports as `off-line'.
Related commands: detach, disable, enable.

cain init

reset integration clock (see Appendix L)

cain cycle default

set cycle period to 10 seconds (see Appendix L)

cain cycle $p$

set cycle period to $p$ seconds (see Appendix L)

cancel

Stops the current pattern (POINTing, Early/Normal or mosaic)
Related commands: point, early.

catie ...

see section 8.8.8 for details of the catie (tied array) commands.

corr[elator] close[file]

Request that CACOR close the current file. You must stop the scan (stop command) before using this command. Look at the CACOR terminal's display to see that the file has closed (the message FITS FILE: CLOSED is displayed on CACOR). A new data file will automatically be opened when a scan is started if a file is not already open.

correlator configure filename

This command will force the correlator to reconfigure using the configuration file filename, so stop the scan and close the file first. Normally this function is performed by the schedule file. Example: corr config full_8_512. In general, use the CACOR command config to configure the correlator.

correlator cycle

Sends the correlator initialisation command and cycle information (integration time or cycle length, blanking interval, offset). When CACOR has been restarted this command will be executed automatically.

correlator stop

Stop CACOR after CAOBS crashes and is restarted. It will start automatically at the next track or start command.

detach ca0n$\vert$all

Disconnect CAOBS from either antenna n or all antenna.
Related commands: attach.

disable auto

Turn off the automatic attenuator setting feature.
Related commands: enable auto, set bypass, set atten, set coarse, show coarse.

disable bell

Turn off the terminal alarm. The terminal alarm is sounded when CAOBS detects an error condition that you should know about.
Related commands: enable bell.

disable ca0n$\vert$all

Disable the drive machinery and turret rotator for either antenna ca0n or all antennas. This will leave everything else as though it was observing.
Related commands: enable ca0n, set atten, attach, detach.

disable correlator

Detach the correlator from CAOBS.
Related commands: enable correlator.

disable tsys

Turn off the $T_{sys}$ scaling of the visibilities. Normal observing procedure is always to have $T_{sys}$ scaling enabled. You may want to turn off tsys in the event of really bad interference.
Related commands: enable tsys.

disable turret ca0n

Disable turret rotation for antenna n. Data will be flagged if the turret is in the wrong position.
Related commands: enable turret.

early $n$

runs early/normal scan on source $n$ in schedule.
Related commands: cancel.

enable auto

Turn on the automatic attenuator setting feature. CAOBS automatically adjusts the settings so that the gated total power is in the optimum (1.5-3.5V) window.
Related commands: disable auto, set bypass, set atten, set coarse, show coarse.

enable bell

Turn on the terminal alarm. The terminal alarm is sounded when CAOBS detects an error condition that you should know about.
Related commands: disable bell.

enable ca0n$\vert$all

Enable the drive machinery for either antenna ca0n or all antennas. Use this command if CAOBS reports that the antennas are disabled.
Related commands: disable ca0n, attach, detach.

enable correlator

Attach the correlator from CAOBS.
Related commands: disable correlator.

enable tsys

Turn on the $Tsys$ scaling of the visibilities. Normal observing procedure is always to have $Tsys$ scaling enabled.
Related commands: disable tsys.

enable turret ca0n

Enable turret rotation for antenna n.
Related commands: disable turret.

exit

Stop CAOBS and return to the XBONES VMS system operating level.

extend

Stop cycling through scans in a schedule file and continue the current scan indefinitely.
Related commands: next.

init

Initialise all CAOBS parameters to default values. This is equivalent to exiting CAOBS and restarting, only faster. Treat this command with caution.
Related commands: reset.

next

Move to the next entry in the schedule, i.e., move to the next scan. This command will cancel an extend command and has no effect in mosaic mode.
Related commands: extend.

point $n$

runs point scan on source $n$ in schedule.
Related commands: cancel, set point_pattern, set point_ifflag, set point_antennas ####.

offset ca0n$\vert$all daz del

Force either antenna ca0n or all antennas to track a position offset from that specified by the schedule file; daz, del are the azimuth and elevation offsets in arcminutes. The offsets cease to apply at the next drive request (i.e., at the next start or track command or when the next scan starts).

redraw

Refresh the screen.

reset ca0n$\vert$all

Resets the ACC for antenna n, or all ACCs. Do not restart your observations until after the antenna image in the ATDRIVEMON display has returned to `normal'.

See Section 7.2.4 on page  for information on resetting the ACC if you can't reset from within CAOBS.

set analogue$\vert$dsd

Calculate ${\mathrm T}_{\mathrm sys}$ measurements and attenuator changes in either analogue or digital form.

set atten ca0n jk[lm]

Set the fine attenuation levels of the samplers. where j is the fine attenuator level for A1, k is the level for B1, l is the level for A2 and m is the level for B2. Each attenuator step introduces (or removes) 2dB of attenuation. There are 8 fine attenuator steps (0-7). Setting fine attenuators does not effect the signal phase or amplitude.

In general this command should be executed while CAOBS is `observing' (i.e. the correlator is in the `go' state).

One might expect that it would be important to switch off the CAOBS automatic sampler level setting feature with the disable auto command before setting attenuator, however, in practice this is not, generally, necessary.
Related commands: sho atten, show coarse, set coarse, show mm, set mm, enable auto, disable auto, set bypass.

set aver n

Average your data in time (note, this can also be set in SCHED) - n is the number of integration cycles (which are typically 15, 20 or 30s) to be averaged. Stop the scan before using this command. When observing large fields you should be careful not to average so much that you significantly distort your image (azimuthal smearing caused by time averaging increases linearly with distance from the phase centre). Refer to Appendix D of Killeen (1993) for details. The current averaging time is displayed on the CAOBS screen.
Related command: show status.

set bypass

The automatic attenuator setting feature waits until the antennas are on source before adjusting the levels. Use this command to activate the feature as soon as a new scan starts. This feature is switched off by using init.
Related command: enable auto, set atten, disable auto, set coarse, show coarse.

set coarse ca0n jklm

Sets coarse attenuators. j,k,l,m The default values are those those from the most recent observations at this frequency and bandwidth or, if there are no recent observations, the values are set to 1. There are four coarse attenuator steps (0-3) Each coarse attenuator step adds (or removes) 6dB of attenuation.

In general this command should be executed while CAOBS is `observing' (i.e. the correlator is in the `go' state).

Note: The coarse attenuators should be adjusted at the beginning of the observations, ie. before applying cacal as this command produces a step in the phase and consequently cause a discontinuity in the delays. If you are forced to use this command in the middle of your observing run, you should observe your secondary calibrator first, change the coarse attenuators and observe the secondary calibrator again. The phase measurements on either side of a set coarse command are independent and separate calibration of the data is necessary.
Related commands: show coarse, disable auto, enable auto, set bypass, show atten, set atten, show mm, set mm.

set diode on/off/switching

Controls the noise cal. Switching is required for standard observations. On and Off are maintenance modes.

set el_limit

Define the elevation limit. The hardware limit is 12°. You can use this command to skip sources in your schedule file below a certain elevation. Please type init at the end of your run so you don't surprise the next observer.
Related commands: show el_limit, set rise_time.

set file filename

Load the schedule file filename, which must be in the directory $ATCA_SCHED on XBONES. Details of the schedule will appear on the topmost section of the CAOBS screen. Enter the start command to initiate an observation using this schedule file.
Related commands: show file.

set genset_on ALL$\vert$CB$\vert$CAOn

Turn on ALL generators, or generator for the control building only, or generator for antenna CA0n, respectively. Use of this operation is restricted to local staff or the Duty Astronomer except in cases of emergency. Observing must be stopped and only attached antenna generators will be started.
Related commands: attach, detach.

set genset_off ALL$\vert$CB$\vert$CAOn

Turn off ALL generators, or generator for the control building only, or generator for antenna CA0n, respectively. Use of this operation is restricted to local staff or the Duty Astronomer except in cases of emergency. Observing must be stopped and only attached antenna generators will be stopped.
Related commands: attach, detach.

set hold n

The HOLD parameter is used to inhibit correlation only during those cycles affected by antenna movement. This command sets the hold period to n times the hold increment for every cycle (normally 512 ms), irrespective of antenna drives. set hold 0 returns to automatic hold calculation.
Related commands: disable hold.

set lo_track_on$\vert$lo_track_off

Turn on/off the local oscillator phase stabilisation. Stop the scan before using this command.

set mm ca0n ab

Set the attenuation levels in the mm receiver. This command only works for the 12mm and 3mm wavelengths. Unlike the fine and coarse attenuators, the first attenuator setting (a) is applied to both `a' polarisations (A1 and A2) and the second setting (b) is applied to both `b' polarisations (B1 and B2). Each attenuator step introduces (or removes) 1dB of attenuation to the signal path. There are 16 mm attenuator steps (0-15).

In general this command should be executed while CAOBS is `observing' (i.e. the correlator is in the `go' state).

Related commands: show mm, show atten, set atten, show coarse, set coarse, disable auto, enable auto, set bypass.

set paddle in|out

Operates W band room temperature paddle

set point_antennas ####

Defines which antennas will have their pointing solutions solved for - so set point_ant 2,3,4 would find pointing errors for antennas 2, 3 and 4.
Related commands: cancel, point, set point_pattern, set point_ifflag

set point_ifflag jklm

Defines the IF channels to be used for pointing, e.g.
$>$ set point_if 12 would select XX and YY for the first frequency.
Related commands: cancel, point, set point_pattern, set point_antennas ####.

set point_pattern #

Specify the # of cycles the antenna will be on any given pointing position during a pointing scan.
If # is a positive number, the pointing mode is selfcal - all antennas move at the same time. There must be at least 4 antennas enabled for this mode of pointing to work.
If # is a negative number, holography mode pointing is executed - the array is divided into 2 sub-arrays and the pointing pattern is executed by the two sub-arrays separately.
Related commands: cancel, point, set point_ifflag, set point_antennas ####.

set reference ca0n

Set antenna ca0n as the reference antenna. That is usually the antenna in the center of the array.
Related commands: show reference

set rise_time [n]

If a source is below the horizon, CAOBS will wait for up to n minutes for the source to rise. If the source will not be up in that time, the array observes the next source in the schedule file.
Related commands: set el_limit, show el_limit, show rise_time.

set scanlength h:m:s

If you set the position to be observed using the track 0 command, you can set the length of the scan.

set servo_on$\vert$servo_off

Turn the automatic sample reference level servoing on/off. During normal observing this is on. Use show tcal on CAOBS to see servoing state.

set source sourcename

If you set the position to be observed using the track 0 command, you can modify the source.

set tt on$\vert$off

Turn the test tone on/off.

show catie

shows status of tied array box when connected

show coarse

Display the current coarse attenuator settings. Related commands: set coarse, set atten, enable auto, disable auto.

show declination

Display the declination of the current source. Use CAMON page /arr to look at the current position being tracked.

show el_limit

Display the elevation limit.
Related commands: set el_limit, set rise_time.

show file

Display the schedule file name.
Related commands: set file.

show frequency c

Display the frequency in MHz of conversion chain c.

show length

Display the length of the current scan.

show mode

Display the epoch currently being used by CAOBS.

show name

Display the name of the current source.

show param

Display the transit time from the control room to the antennas and back.

show point_pattern

Display the pointing pattern during a pointing scan.
Related commands: set point_pattern, set point_ifflag, set point_antennas ####, cancel, point.

show ra

Display the Right Ascension of the current source. Use CAMON page /arr to look at the current position being tracked.

show reference

Display the current reference antenna.

show rise_time

Display the time that CAOBS will wait for a source that is below the horizon. Related commands: set rise_time

show start

Display the Universal Time of the current scan's start.

show status

Display general array information.

show tcal

Display system temperatures.

start [n[/m]

] Commence observations once you have used the set file command to load your schedule file. This command opens a data file and starts a scan. See below for mosaicing. If you omit n/m then CAOBS starts a scan at the first object in the schedule file and stops after the last scan in the file. If you give a value for n then CAOBS starts a scan at the nth object in the schedule file. At the end of this scan, CAOBS starts a scan for the next object in the schedule file and so on until the end of the schedule file. If you include a value for m, then CAOBS repeats all the scans in the schedule file m times. If the source sets, CAOBS will send the array to the next source which has not set.
Related commands: stop, track, correlator closefile.

Warning: if all of your sources are set while this command is still being carried out, then you will get the same number of terminal beeps and twice as many lines of error messages as the number of sources you have asked to be observed (e.g., for sources that are set when the start command is run, m times the number of sources!).

For mosaic mode observing, the format for the command is start n,k/m, where n is the scan number in the schedule file, k is the position (data line number) in the mosaic file and m is the number of times to repeat the whole process.

stop

Stops the current scan. The antennas will stop moving. Use the correlator closefile command to close the data file. A stop command is always sent to the antennas, even if no scan is underway.
Related commands: start [n]/[m], track, corr closefile.

stow [ca0n]

or stow [n] Drives antenna ca0n to azimuth 90° and elevation 85°. Brakes are applied to the drives once this position has been reached. If you omit ca0n then all antennas are stowed. To start observations after a stow, just use the start or track commands.

systime

Synchronise the clocks on CACCC and XBONES to the station clock. This is done automatically at the beginning of every scan.

track [n]

Track the source in scan n of the current schedule file continually until a stop command. If n is omitted, track the first source in the schedule file. If n=0 use the current settings, but allow them to be modified by the set command.
Related commands: start [n]/[m], stop, corr closefile.

wrap north$\vert$south

Specify the desired wrap, after stopping the scan. Then restart the scan. The command that follows this must be a start or track command. Anything else will cancel the request.