This report provides the updated schematics, board
layouts, and source code for the actual production version of the encoder
electronics upgrade. This is what is going into the VLA antennas as
you read this.
The schematic images are provided in two file formats:
*.gif for easy viewing, and *.ps for better-quality
printing. The final board designs are provided as gerber files that
you are welcome to make boards from. There are two modifications that
you should make, however. These are noted below.
ENCODER COARSE AND FINE DRIVER
Note: we had trouble with using the BRCX11 resolvers at 10kHz. Since the prior resolvers worked great at this frequency I hard wired production board so that the frequency select pins of U3 for 10kHz: pin 1 to VSS and pin 2 to GND. To get the system to work with the BRCX11 resolvers, I changed the frequency to 2kHz by drilling out pin 2 of the board where the socket for U3 sits and connecting pin 2 to pin 1. The schematic reflects this change, but the board is wrong.
Three programs are provided. Listing enc1x.asm
is for the PIC16C55 that resides in the encoder. This program reads
the coarse and fine resolver-to-digital converters and ships the data
down the fiber. The "1x" designation means that this program works
for the 1x gearbox on the coarse resolver. The listing
buffer.asm runs the PIC16C55 in the Data Receiver/Buffer which
reads the fiber data stream and make it available to the controller.
The controller code is enc_kbd.c and is put on the BL1600
EPROM along with the ZWorld BIOS.
These programs are provided in both HTML form for nice
viewing in a browser, or downloadable ASCII.
These programs are covered by the Gnu Public License