ELECTRONICS NEWS
 
Dome Operation System for 3.5m Telescope

Regarding the modernization of the telescope electronics, a wide part of the dome operation has been renewed.
Considering the costs, time expenditures and benefits, the selection fell onto an operation system which works with PC´s (Programmable Controllers). PC´s are microprocessor controlled one-output units device, that by mean of interface modules and analog-digital converters make a flexible environment.
The use of 6 PC´s could eliminate hundreds of electromechanical components.
The most important changes applied for the new dome operation system are the following:
  1. Simple communication with the TECS (Telescope Control System).
  2. Wireless data communication to the moving parts of the dome.
  3. "Dome Automatic System" and "Automatic System Variations" programs, are moved to the Dome Operation System from the TECS.
  4. Operation of dome vents from the observing room.
The old Dome / TECS interface consisted of a great number of parallel one-output modules. Each signal had an associated electromechanical relay to control the In/Out ports of the TECS or to operate the hardware of the dome.
The new PC design needs only a two leads system: the normal RS232C-interface. All commands between TECS and dome are defined in a command list.

Formerly the data communication between the moving parts and fixed parts of the dome were carried out through sliding lines and a special data bus.
The new PC design operates through a wireless data communication RS232 by means of a radio modem link.

PC
PC Mitsubishi FX2N
(SML2400) (MCprof.)
SML2400 (2.4 GHz)
MCprof. (433 MHz)

With the application of PC´s, a part of the TECS software packets could be shifted to the dome operation system:

  • The automatic tracking of the dome opening depending on the Telescope position (Dome tracking).
  • The automatic interchange of the telescope front rings.

    • The new air vents in the moving part of the dome contribute to the improvement of the "Seeing". These flaps can be operated with a separate wireless data communication media.

    Photograph of the  3.5m telescop (399 kByte)
     
    W. Müller (mueller@caha.es)
     

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