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Thoughts on Automation

MOVE computer

This is currently a Pentium III computer running MS-DOS 6.11. The interface to the telescope systems is through 4 serial ports, a PCX-48 motor controller and a video frame grabber used by the guider.

Serial ports:

  • COM1 - guider motor control
  • COM2 - remote control
  • COM3 - barcode reader for dome position
  • COM4 - guider camera control

COM1 and COM3 share an interrupt; the IO is handled by assembly code in com13io.asm, likewise COM2 and COM4 in com24io.asm.

The PCX-48-4E motor controller (data) is managed by the assembly code in pcxio.asm and FORTRAN functions PUTPCX in putpcx.for. PUTPCX() is called from many places in the code with hard-wired command strings.

PCX-48 channels:

  • Axis X is RA (positive to the W)
  • Axis Y is Dec (positive to the S)
  • Axis Z is Focus (positive out at 72)
  • Axis T is dome motor for 72"

The T axis uses the LOTC-07 expansion box, which allows addressing multiple motors (only one used for Dome drive on the 72"). The details are dscribed on page 10 of the perkins manual. Essentially the sequence "AT MR# GO" where # is a small integer indicates address selection.

Telescope motion

Could replace PCX-48 interface in DOS machine with a newer one from Oregon Micro Systems. With care it could be wired into the LOTC "green card box". Commands in Fortran code would have to be updated.

Dome Shutter

This could be done fairly easily by driving the contactor on the dome which is currently controlled by the lever switch. Safety features:

  • Camera viewing the shutter opening
  • Speed monitor on the winch drum
  • Computer readback of the limit switches

Dome Rotation

Dome rotation is controlled by the T axis of the PCX-48 controller, while the current position is read by a barcode reader on COM3, see subroutine BARCODE in barcode.for.


This would probably need to be completely redone.

Last modified 5 years ago Last modified on May 29, 2018, 12:55:44 PM