Introduction

The process DUMMSY, by itself, or combined with its GUI TkDs, provides a simple means of driving ATNF backend ( or correlator ) control computers ( CCCs ). It is mainly used to test the backends, providing the information and stimuli required to run the CCC. In this role it is used as a substitute for the main ATNF observing programs, CAOBS or TCS.

The commands listed below can be delivered to DUMMSY from three different sources:

  • By typing the command at the } prompt in the window from which the DUMMSY process was started.
  • From the TkDs GUI, either from buttons or entry fields, including the command entry field.
  • From the external command socket connected to port DS_COMMAND_PORT, defined in the parameters file, pointed to by the "cor_parameters_file" environment variable.

In general, with commmands used to enter parameters, entering the command by itself with no parameters, will result in a printout of the current settings of the parameters.

Commands

go [HH:MM:SS.sss]

Causes the backend to start cycling. If a data file is open, this command signals the start of a new scan. A scan header will be written. If a time is given, the scan will start at this UT. Otherwise, a start time will be chosen which is an integer multiple of the cycle period.

stop

Causes the backend to stop cycling. If a data file is open, this command signals the end of the current scan.

cyc[le] [period [blank [hold [switch] ] ] ]

Send a CYCLE message to the CCC. This defines the timing of the backend cycle. If given, the parameters, all in decimal seconds, define new parameters for the cycle. They are listed below. The default settings are set in the DEFAULT_CYCLE entry in the parameters file. The blank, hold and switch parameters are not relevent to some configurations.
  • period - the integration cycle period, in the range 2.0 to 30.0 seconds.
  • blank - the cycle blank time, in the range 0.01 seconds to period.
  • hold - the hold time quantum, only used in ATCA mosaicing mode.
  • switch - the period of the calibration switching signal.
Note: Both period and blank must, in general, be integer multiples of switch.

conf[ig] [name]

If name is given, the CCC is instructed to configure the backend to the configuration "name". Otherwise the CCC is instructed to enter its configuration process in interactive mode. In this mode existing configurations can be modified and new ones created. A special case is where name = ".". In this case, the CCC will configure the backend to its current configuration.

fo filename

Causes a data output fits file named "filename" to be opened.

fc

Causes the currently open data output fits file to be closed.

ant[ennas] ant1 [ant2 [ant3....... ] ]

Defines the names of the antennas which will compose the antenna table written in the data output fits file antenna table. Names beginning with "MB", "CA" and "#" have special significance for ATNF facilities and should be avoided.

obse[rver] observers_name

obst[ype] [type1 [type2 [type3 ....... ] ] ]

Defines the type of observation which can be any reasonable combination of the following types.
  • NORMAL - Standard mode - no special flags set.
  • FQSW - ATCA Frequency switching mode
  • MOSAIC - ATCA Mosaic mode
  • PSR - Pulsar binning mode
  • WBPSR - Wideband pulsar mode - required for all pulsar digital filter bank (DFB) observations.
  • REF - Next scan is a reference scan in position switched spectral line mode.
  • MBFQSW - Slow frequency switching mode. The frequency is switched every cycle.
  • F_FQSW - Fast frequency switching mode with the Parkes Multibeam correlator.
  • SCAN - Telescope scanning mode.
  • TRACK - Telescope tracking mode.
  • PADDLE - Next scan has the calibration paddle switched in. Used for the calibration of mm-wave receivers.

sou[rce] name ra dec epoch

The source parameters. ra in the format hh:mm:ss.sss, dec in the format [-]dd:mm:ss.sss

freq frequency_1 [frequency_2]

Defines the band centre frequencies, in decimal MHz.

rfreq rest_frequency_1 [rest_frequency_2]

Defines the rest frequency, in decimal MHz, of one spectral line contained in each band.

bw bandwidth_1 [bandwidth_2]

Defines the bandwidth, in decimal MHz, for each band.

finv[ert] yes/no [yes/no]

If "no" then the sky frequency increases with increasing backend channel number.

chan[nels] freq_1 [freq_2]

Defines the range of frequency channels to be written to the data output fits file for each frequency band. The parameter[s] can be "all" or "0-0" for all channels, or "ff-ll", where ff is the first channel number and ll is the last channel number.

Note: The last command entered from the set [freq,rfreq,bw,finv,chan] will define, by way of the number of parameters given, the number of active frequency bands.

tsys fn a1 b1 [a2 b2 [a3 b3 ....... ] ]

Defines the tsys values for polarisations a and b of antennas 1,2,3..... for frequency band n. The ai and bi tsys values given should be the square root of the actual system temperatures in the chosen units.

tsys e

At the start of the next scan, enables the amplitude calibration based on the given, or measured, tsys values.

tsys d

At the start of the next scan, disables the amplitude calibration based on the given, or measured, tsys values. A tsys value of 500 units is assumed for all antennas.

avg n

Defines the number of backend cycles for which the data will be averaged before being written to the output fits file.

ccc command_text

Send the text string command_text to the CCC via the CCOMMAND message. This provides a means of entering commands which are normally local to the CCC controller via DUMMSY.

q[uit] or ex[it]

Exits the program.

Special PULSAR Backend Commands

proj[ect] [project_name]

Defines the project name which is written in the header of the fits data output file.

sit[e] [site_name]

Defines the site name which is written in the header of the fits data output file.

fro[ntend] [frontend_name]

Defines the frontend (receiver) name which is written in the header of the fits data output file.

bac[kend] [backend_name]

Defines the backend name which is written in the header of the fits data output file.

psrc[al] [start_phase width]

Define the control of a calibration signal which is synchronous with the pulsar period. The start phase and width are in fractions of the pulsar period. If no parameters are given, the current settings are displayed. If the start phase is greater than or equal to zero, and the width is greater than zero, the calibration signal is turned on. If the start phase and width are set to zero, the calibration signal is turned off.

[no]fol[ding]

Enable or disable pulsar folding mode. If folding mode is enabled, pulsar search mode is disabled.

[no]sea[rch]

Enable or disable pulsar search mode. If search mode is enabled, pulsar folding mode is disabled.

sset

Enable pulsar search set mode. If search set mode is enabled, pulsar folding mode is disabled. A search set scan is used to determine calibration parameters which are used in subsequent search mode scans.

[no]apsr

Enable or disable pulsar apsr mode. Apsr mode can co-exist with all other modes.

[no]rfi

Enable or disable pulsar rfi mode. Rfi mode can co-exist with all other modes.

psrob[smode] [string]

Without parameter, show the current setting of the obsmode parameter in the PSRHDR message.
With parameter, set the obsmode parameter in the PSRHDR message to the given string.
The obsmode parameter is also set by the [no]folding, [no]search and sset commands.

snp[roducts] n

Set the number of products to collect in pulsar search mode to n. Valid values on n are 1, for AA and BB polarisations combined, 2, for AA and BB polarisations, and 4, for AA, BB and AB real and imaginary.

snb[its] n

Set the number of bits to which the search mode data is quantised to n. Valid values of n are 1, 2, 4 or 8.

ssamt[ime] x

Set the sample time for pulsar search mode to x, in seconds. The default is 1.0E-04 = 100us.

stc[onstant] x

Set the time constant for producing the average bandpass during pulsar search mode to x, in seconds. The default is 1 second.

sps[ub] n

Set the number of samples per subint for pulsar search mode to n. The default is 2048.

smfs n

Set the maximum file length in seconds for pulsar search mode to n. The default is 0, which means that the file will remain open for the entire scan. Otherwise, the current file will be closed and a new one opened after each successive n second interval throughout the scan. In this case multiple files are written, each no longer than n seconds in length, with "_K" appended to the filename and K incrementing with each new file.

apnba[nds] n

Set the number of bands to output in pulsar apsr mode to n. The default is 4.

apnbi[ts] n

Set the number of bits to which the apsr mode data is quantised to n. Valid values of n are 1, 2, 4 or 8.

rficli[p] n

Set the pulsar rfi time domain mode clipping level to n. The valid range for n is 0 to 65535. The number represents the square of the voltage at which clipping will occur, where the voltage is in the same units as the reported digitiser rms values.

rficlt[c] x

Set the pulsar rfi time domain mode clipping time constant to x microseconds. The setting is quantised to 2**n microseconds, in the range 2 to 128 microseconds.

rfiint[time] x

Set the pulsar rfi excision mode integration time to x seconds.

rfig[ain] x

Set the global pulsar rfi excision mode gain to x. The valid range for x is 0.0 to 1.0.

Special Parkes Multibeam Correlator Commands

[no]mbsam

At the start of the next scan, enables or disables the Multibeam Sampler total power data acquisition. Disabled on startup.

mbtp [OFF]

At the start of the next scan:

Without parameter, turns on the Multibeam fast sampling total power mode. This disables the correlator. With parameter = OFF, turns off this mode and returns to normal correlator operation.


Last updated: Warwick Wilson 20 January 2012

Warwick.Wilson@csiro.au
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