next up previous contents
Next: SPD Up: index Previous: LBACOR   Contents

The Correlator Schedule File

Here is the schedule file for a demonstration experiment. It is a basic file, just containing the essentials. Far more complex files can be written and a schedule file for a real experiment (v119a), is shown afterwards. You will see that the S2 transports as well as the correlator can be controlled through the schedule file.

----------------------------------

;LBA experiment file
EXPERIMENT V123

;Reference Date, day number
DATE 1998 053

;Freq(MHz) Bandwidth (+'ve for USB, -'ve for LSB)
FREQ/BW 4938.0 16.0 4954.0 16.0

SOURCE_LIST NEOS_9609

ANTENNAS 3

;NAME TSYS/MODE1 TSYS/MODE2 Delay(us) at T0(secs) rate(us/s)
PKS 100.0 0 100.0 0 0.0 0/00:00:00 0.0
MOP 400.0 0 400.0 0 2.0 0/00:00:00 0.0
HOB 1000.0 0 1000.0 0 -10.0 0/00:00:00 0.0

CONFIG 3B_16_64_2F

;Scan Source Scan start Scan stop
1 1622-253 0/21:57:30 - 0/22:15:04
2 1622-297 0/22:15:10 - 1/02:30:30

STOP
FILE CLOSE
;----------------------------------

The various sections of this file are now described in turn.

An ';' in the first column indicates that this line is not read by lbacor. This allows comment lines and blank lines to be included for readability, as well enabling a schedule to be written for a series of tapes with appropriate commands commented in or out as needed.

EXPERIMENT $<$expt_name$>$ The number/name assigned to this experiment. Optional, unless pulsar binning is used.
     
DATE $<$year$>$ $<$day_of_year$>$ Defines the year of day-of-year of the start time of the first scan in the schedule. This is the reference day for the rest of the expt.
     
FREQ/BW $<$freq1

$>\hspace{0.3cm}<$bw1$>$

 [$<$freq2$>$ $<$bw2$>$]
    Defines the centre sky frequency and bandwidth in MHz of each of the observing bands to be correlated (minimum of 1, maximum of 2 bands).The observing frequency is taken at the centre of the recorded band. The bandwidth must have a value of $\pm$ N, where N is currently contained to the values 2, 4, 8, 16. Narrower bandwidths than 2MHz are not yet implemented.
     
SOURCE_LIST $<$source_list$>$ Points to a file containing a list of source names and coordinates to be used in the correlating. The full file name is;
COR$DB:$<$source_list$>$.TAB
and must contain entries in the following format;
0537-441 05:38:50.3615 -44:05:08.939
0537-441 05:38:50.3615 -44:05:08.939

where the coordinates must be given in equinox/epoch J2000. The existing file NEOS_9609.TAB contains the USNO VLBI reference-frame list and may be used to find positions for calibrators.
     
CONFIG $<$config_name$>$ Defines the correlator configuration to be used. Consult with correlator personnel to determine the appropriate configuration.
     
ANTENNAS $<$n$>$ Defines the TSYSes, data format and clock parameters for each antenna (S2 playback) to be correlated. The ANTENNAS keyword must be followed immediately by n lines of the form;
 
name TSYS1 mode1 [TSYS2 mode2] delay ref_time rate [foff1 [foff2]]
 
where;  
name - pre-defined antenna name. See the file COR$DB:stations.tab
TSYS1 - the approximate TSYS of the antenna (frequency #1), for nominal on-line calibration
mode 1 - data mode of the antenna, as follows;
 
0 - normal
1 - if sign and mag bits swapped (Hobart data prior to 1-Aug-1996),
2 - if sampling is VLBA mode (offset binary) rather than AT mode (true sign/magnitude),
4 - to invert the recorded spectrum (e.g. if data were recorded LSB instead of USB).
TSYS2 - TSYS for frequency #2, if and only if defined
mode 2 - data mode for frequency #2, if and only if defined
delay - station clock offset in microseconds. A slow clock takes a positive value.
ref_time - specifies a reference time for the delay in the form dd/hh:mm:ss, where relative day dd is the offset from the reference day-of-year defined in the DATE line.
rate - clock rate in $\mu$s/s. Again, a slow-running clock takes a positive value.
foff1 - frequency offset for frequency #1, in Hertz. An actual observing frequency higher than the nominal frequency (in FREQ/BW) takes a positive value.
foff2 - frequency offset for frequency #2, if and only if the latter is defined.

The Schedule Section
The individual scans are now defined, along with commands to control the flow of the correlating. For fringe-searching, it is sufficient to specify only scan information. Additional commands to automate the processing are described later.

$<$n$>$ source dd/hh:mm:ss - dd/hh:mm:ss

Defines a scan on the named source, with the specified start and stop times (UT). The relative day dd is measured from the reference day defined in DATE $<$year$>$ $<$day_of_year$>$

Another Example Schedule File

In this next example schedule file is from a real experiment - V119. In this example file you can see that you can also control the S2 transports from within the schedule file. Stopping tapes, rewinding them, changing groups, realigning etc is all possible. Also you can open and close new data files, change correlator configurations as so on. It is also posible to allow transports to be taken offline for intermittent periods of time if no data was recorded at one station due to problems at that station.

The usual practice is to use combinations of all the available commands within the schedule file to allow several days observing of the one experiment to be written into the one schedule file. You can include all the configurations you'll need, all the source scans and all the tape changes required. You can then simply comment in or out the appropriate sections to allow correlating of particular time ranges and/or tape sets.

One thing to note: all commands issued to the S2 transports (the VCR's) from within a schedule file are straight forward. If however you wish to control the S2s manually through LBABOSS - all commands are prefixed with ``s2''. For Example - rewinding and stopping are controlled by the commands ``rewind'' and ``stop'' in the schedule file but if issued through LBABOSS would be ``s2rewind'' and ``s2stop''

Note: Use the PAUSE command with care. If, for example, PAUSE is issued directly after REWIND, and then followed by PLAY,

REWIND
PAUSE 360
PLAY

then the pause time starts directly after the rewind begins. If the pause time is shorter than the time to perform the rewind, the correlator appears to miss the play statement.

Here is the schedule file

; LBA experiment file:
EXPERIMENT V119A2

; Reference Date, day number
DATE 1998 310

; Freq(MHz) Bandwidth (+'ve for USB, -'ve for LSB)
FREQ/BW 1420.00 +4

TICK 0.040
HOLD 0.020
SOURCE_LIST V119

ANTENNAS 4

;NAME TSYS mode Delay($\mu$s) at T0(secs) rate($\mu$s/s)
PKS 30.0 0 0.0 0/00:00:00 0.0
MOP 400.0 0 0.12 0/00:00:00 0.0
HOB 1000.0 0 -10.0 0/00:00:00 0.0
CAT13 80.0 0 -53.54 0/00:00:00 0.0

;
; All recorded nominal USB, in order RCP,LCP except Parkes, which
; recorded dual-linears (multibeam receiver central beam).
; NB large clock offset at Mopra was reset to zero at 310/0000UT.
;
; Config for Autocorrelations
;config 4A_AC_4_2048_2P
;
; Configs for Fringe-finding
;config 6B_4_512_4P
;config 6B_4_64_4P
;
; Config for first pass: baselines 12,13,23
;CONFIG 3B_4_1024_4P
;
; Scan Source Timerange
;
; Pass 1: baselines 12,13,23.
; Manually align tapes to 1117UT.
;
;file v119a2_1100p1.rpf
;file v119a2_ac_1100.rpf
;group 0
;align 11:30:00
; 1 1934-638 0/10:00:00 - 0/11:45:00
; 2 0637-752 0/11:45:10 - 0/15:00:00

;stop
;rewind
;file v119a2_1500p1.rpf
;group 1
;align 15:00:30
; 2 0637-752 0/15:00:00 - 0/15:20:00
; 3 0537-441 0/15:20:10 - 0/16:00:00
; 4 0637-752 0/16:00:10 - 0/19:00:00

;stop
;rewind
;file v119a2_1900p1.rpf
;offline 4
;group 2
;align 19:00:30
; 4 0637-752 0/19:00:00 - 0/19:40:00
; 5 0537-441 0/19:40:10 - 0/20:20:00
; 6 0637-752 0/20:20:10 - 0/23:00:00

;stop
;rewind
;file v119a2_2300p1.rpf
;offline 4
;group 3
;align 23:00:30
; 6 0637-752 0/23:00:00 - 1/00:00:00
; 7 1253-055 1/00:00:10 - 1/01:00:00

;stop
;rewind
;file close
;
; Pass 2
;group 0
align 11:16:40
CONFIG 3B_4_1024_4P-2
;
file v119a2_1100p2.rpf
1 1934-638 0/10:00:00 - 0/11:45:00
2 0637-752 0/11:45:10 - 0/15:00:00

stop
rewind
file close
; There is probably no AT data past 1500UT (NOEL failure), so stop here.

next up previous contents
Next: SPD Up: index Previous: LBACOR   Contents

Paul Jones 2003-06-13
ASKAP
Public