Frontend Interfaces Russell O Redman Frontend Interfaces Overview

Frontend Interfaces Russell O. Redman

Frontend Interfaces Overview • Frontend role is simple with automated tuning – given a frequency, load, etc. tune to that frequency, direct the beam to the load, etc. – report the current frequency, load, etc. to the OCS • In normal operation the frontend is controlled using DRAMA actions issued by the TODD – INITIALISE, CONFIGURE, TUNE, SEQUENCE, . . . – Arguments are passed in XML files generated by the translator » XML files will usually be small and simple • 0 or more name-value pair • NOT necessarily disk files (may be character strings)

Frontend Interfaces DRAMA actions for Observing • Major actions – – INITIALISE CONFIGURE TUNE SEQUENCE • Minor actions (possibly superfluous) – – – LOAD BALANCE SHIFT_FREQ TRACK FSW TEST 1

Frontend Interfaces Format of discussion • Interface 1 » » item 1 new item depreciated item etc. • Interface 2 » item 1 » etc. • Comments

Frontend Interfaces - Major INITIALISE • Translator to Frontend » Simulate (0. . 3) • None=0, Hardware=1, Network=2, Hardware. And. Network=3 » FE_Init_File(s) • sets values for variables that are not frequency-dependent • disk file with possibly a large number of name-value pairs • possibly several files? – Tuning curves, active mixer mask, . . . » Debug • (TRUE | FALSE) or (ON | OFF)? • Motor controller will home axes, so will take up to 1 minute to return.

Frontend Interface - Major CONFIGURE • Translator to Frontend » » » » » load nu_rest[] nu_if[] sideband nu_offset_scale FE_active_channels[] sb_mode vel_source vel_defn vel_ref » centre_corr (SKY | AMBIENT | LOAD 2) rest frequency GHz IF frequency (GHz) (USB | LSB) (frequency switching scale MHz) array of (GOOD | UNSTABLE | BAD) (SSB | DSB) [ SSB for HARP-B ] source velocity km/s (RADIO | OPTICAL | RELATIVISTIC) (TOPOCENTRIC | GEOCENTRIC | HELIOCENTRIC | LSR) (TRUE | FALSE)

Frontend Interface - Major CONFIGURE (cont. ) • Frontend to PTCS – DOPPLER » vel_source » vel_defn » vel_ref » centre_corr DRAMA parameter or DRAMA action with real return value source velocity km/s (RADIO | OPTICAL | RELATIVISTIC) (TOPOCENTRIC | GEOCENTRIC | HELIOCENTRIC | LSR) (TRUE | FALSE)

Frontend Interfaces - Major TUNE • Translator to Frontend » Completeness (FULL | AUTO | ELECTRONIC) • Frontend to PTCS – DOPPLER DRAMA parameter or DRAMA action with real return value

Frontend Interfaces - Major SEQUENCE • Translator to Frontend » » default state (FREQ_OFFSET = 0) state 1 (FREQ_OFFSET = 1). . . State N (FREQ_OFFSET = (1 | -1) • RTS to/from Frontend » SC » SR » DV from RTS to RTS from RTS • Frontend to PTCS (Doppler tracking ON) – DOPPLER

Frontend Interfaces - Major SEQUENCE (cont. ) • Frontend to ACSIS DR » » » » current values of all CONFIGURE parameters (includes LOAD) Sequence Number FE_NULO DOPPLER FREQ_OFFSET TEMP_AMB TEMP_LOAD 2

Frontend Interfaces - Minor LOAD • Translator to Frontend » load (SKY | AMBIENT | LOAD 2) • Comments: – The load could be specified in CONFIGURE » CONFIGURE does not move anything » TUNE will always update at least electronic tuning – LOAD completes in one action what would require two using CONFIGURE and TUNE

Frontend Interfaces - Minor TRACK (Doppler tracking) • Translator to Frontend – FE_Track (ON | OFF | UPDATE) • Comments: – FE_Track (ON | OFF) could be added to CONFIGURE – TRACK FE_Track=UPDATE is equivalent to TUNE Completeness=ELECTRONIC – If FE_Track=ON, when should the Doppler factor be updated? » At the start of a SEQUENCE? » Every second, gated by SEQUENCE? – How often is Doppler tracking actually used?

Frontend Interfaces - Minor BALANCE • Translator to Frontend – N/A • Comments – – Directs the beam to the hot load (warmer of AMBIENT or LOAD 2) Adjusts IF attenuators to optimum levels Redirects the beam to SKY Does NOT adjust other parts of the receiver

Frontend Interfaces - Minor SHIFT_FREQ • Translator to Frontend – OFFSET _FREQ MHz • Comments: – Used in slow frequency switching – Equivalent to SEQUENCE with a single state

Frontend Interfaces - Minor FSW • Translator to Frontend – N/A • Only for compatability with existing systems – issue a warning and return success

Frontend Interfaces - Minor TEST 1 • Translator to Frontend – Level = 1 • Comments – This has been mentioned as a way to check the receiver lock, with the idea that it should be used at the start of every sequence. I think this is not the correct way to test the lock! – TEST 1 reads current values for all hardware variables and returns TRUE if everything seems OK, FALSE otherwise. The lock check is a side effect of this test. – Will this be used in TODD recipes?

Frontend Interfaces Miscellaneous Housekeeping • • • EXIT PING READ_TEMP SET_TEMP TEST WRITE_DATA