Interfacing Issues
Interfacing with the shack unit operates in a number of different ways
AZ/EL board to shack unit
Via the 9 pin sockets on the rear of the shack unit connections should be made through pins:
| Pin on DB9 | Function |
| 1 | 12V to AZ/EL board's voltage regulator |
| 3 | 9600 baud data IN to shack unit |
| 5 | Earth - 0V |
| 7 | Handshake out to ant unit |
The connections to the Elevation and Azimuth ports should be identical. The shack unit determines if the information is Azimuth or Elevation depending on which port is in use. Note that if a plug or socket is mounted on the AZ/EL board the hardware should be mounted on the soldering side of the board, otherwise the pins will not match up with the shack unit. Sorry about this layout error.
Note that there is a different wiring pattern required on J3 if you use the AD2-B interface from US-Digital. See the separate document in Encoders.
Potentiometer connections to DB9
| Pin on DB9 | Function |
| 4 | +5V out to top of potentiometer |
| 5 | 0 V (earth) |
| 8 | Wiper of pot |
Computer connection to DB25
| Pin on DB25 | Function |
| 2 | 9600 baud IN from comp - RS232 levels |
| 3 | 9600 baud OUT to comp - RS232 levels |
| 5 | CTS to computer (TTL unless wired differently see manual) |
| 7 | Earth |
| 20 | DTR from computer (TTL unless wired differently see manual) |
With computer connections some computers are more forgiving than others. Some will work quite nicely with TTL levels on their serial ports while others need RS232 levels. See the manual for more interfacing detail on this. It is suggested that initially the DTR line in the shack unit not be connected to pin 20 but instead it is connected to pin 7, that is 0V. This results in the DTR line from the computer being left floating when standard cables are used. This can be quite important because a negative voltage on the 18F4620 input port for DTR can have quite an affect on performance. If your computer does need RS232 levels see the manual regarding activating the level converter in the MAX232.
Large Display Connection to DB25
| Pin | Function |
| 3 | TTL data out of shack unit to display interface |
| 7 | Earth |
Using Orbitron
Orbitron is an excellent program for tracking satellites (not so accurate for moon or sun though). The shack unit interfaces well to Orbitron thanks to the excellent programming support provided by the author. Note that in January 2008 I fixed a problem with the Update Time function which did not allow for summer time.
Here is the manual describing how to interface Orbitron to my shack unit.
Using EME tracker by Doug VK3UM
Doug's excellent EME tracker program interfaces to the shack unit through the serial port. Here is the latest copy of his program.
Programmers: How to interface to the VK5DJ Beam Rotator Controller
Download this zip file that contains a document describing the issues and some sample Delphi code.