Remote or Robotic Operation

The telescope is primarily designed to be operated remotely or robotic. The main interface is the Beckhoff ADS connection to the TelescopeControl by setting the respective variables listed below. Since the ADS communication cycle is in the order of tens of seconds this can be considered a realtime interface.

The following conditions have to be met for remote or robotic operations:

  1. The main power switch is turned ON.

  2. The brake clearance is OPEN (ON).

  3. The pendant control has the MANUAL set to OFF.

  4. The selector on the pendant control is in setting 15, 14 or 11.

API Description

Since ADS does not implement protected variables, specific input and output variables have been defined.

Input Variables

  • power: activates the the telescope. The telescope performs the following actions:

    1. activate the hydraulic pumps (Hydraulics System)

    2. opens the covers (Telescope Covers)

    3. enable the elevation and azimuth

    4. enable the dome, if available (Dome Operation)

    5. enable the de-rotator (De-rotator)

    6. enable the filterwheel (Filter-Wheel)

    7. enable the focuser (Focus)

    If the power command is issued for the first time after a hard-reset or power-cycle, the calibration cycle for each axis will be performed. When disabling the power signal the axes will be disabled in reverse order and the covers will be closed.

  • gohome: The telescope moves to the hard-coded home position. Azimuth 180 degrees and elevation 45 degrees.

  • park: the telescope moves to the hard-coded parking position and closes the covers. After reaching the parking position, the telescope is powered down.

  • ra: new right ascension. Issue a goto command to move the telescope there.

  • de: new declination. Issue a goto command to move the telescope there.

  • track: start tracking at the current position. This operates the elevation, azimuth and de-rotator axis.

  • goto: moves the telescope to the ra and de position.

  • stop: aborts the current movement of the telescope.

  • pumping: moves the telescope and the de-rotator to the hard-coded position for pumping the Dewar.

  • reset performs a reset of all axis errors.

  • elevation_offset: offset for the elevation in degrees.

  • azimuth_offset: offset for the azimuth in degrees.

  • time_offset: offset for the time in seconds.

  • derotator_offset: offset for the de-rotator in degrees.

  • Nasmyth_port: desired Nasmyth port (1 or 2).

  • focus_position: position in millimeters for the focuser.

  • filter_position: new position of the filter-wheel (0…23).

Output Variables

  • ready: signals that the last command has been executed and the telescope is ready for a new command.

  • error: signals an (axis-)error

  • errorid: NC axis error number

  • sliding: the telescope is moving to a new position

  • tracking: the telescope is in tracking mode and follows the set right ascension and declination position.

  • stopped: the telescope is not moving.

  • slewtime: time in seconds, until the telescope reaches its goto-position.

  • tracktime: time in seconds, until the telescope will reach a limit-switch.

  • homed: signals if all axis are calibrated.