LX10 KORNER




•Introduction
•Skyguider
•Z88
•Optical Encoders
•Hardware
•Schematic
•Notes



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 DIGITAL SETTING CIRCLES PROJECT

Hardware

Interface Box

The interface box contains two connectors - a card connector to the Z88 and a 14 pin Centronics socket to connect it to the telescope connector box. In between there is the electronics which do the job of telling the Z88 which way the telescope has moved and by how far. It does this by decoding the signal pulses from the encoders. Also in the box is an EPROM chip which contains the DSC software and databases to run on the Z88. It is 512K bytes in size.

The card connector is an old 128K EPROM card with its EPROM chip removed and replace by a 28 pin DIL header connect to a grey flat IDC cable. Four other connections are soldered directly to the card's PCB to allow addtional address lines to fed to the interface box. It is inserted into one of the Z88's card slots. The Z88's power sources powers the interface box, LEDs and encoders.

Two Hewlett Packard IC's (chips), HCTL-2016, monitor the pulses from the encoders and supply the Z88 with a count of the postion of the encoders. For my setup the encoders will generate 8192 counts per each complete revolution, going back to 0 after the 8191 count.

A 10 way coiled cable connects the interface box to the telescope connector box via it's Centronics socket. The other end of the cable is a 9 pin D-type female plug.

Telescope ConnectorBox

This box is fixed to the LX10 into the recess at the bottom of the right hand fork mounting. There exists a 5mm, factory drilled, threaded hole along bottom part of the mounting . The box is butted up against the fork arm and secured by a 30mm long 5mm screw. This can be seen in the in the picture below:

Also, in the upper corner of the recss is an elongated hole, just large enough to insert a 9 way D-type male connector. It is possible to secure this in place. To this the coiled cable from the interface box can be connected, as seen below:

The outer part of the D-type connector is used to connect another electrical line to provide a total of 10 lines. These lines have the following purposes:

  1. +5v
  2. GND
  3. CHA from the RA encoder
  4. CHB from the RA encoder
  5. CHA from the Dec encoder
  6. CHB from the Dec encoder
  7. East LED
  8. West LED
  9. North LED
  10. South LED

The connector box has 4 LEDs in a diamond pattern (NESW). These will be lit by the computer to prompt the user to turn the telescope in a certain direction in order to find an object. A maximum of 2 LEDs will ever be lit.