First Generation I/O Cards

The old documentation was gathered from 1988 and put through LaTeX in 2011, with a download:
Digital Interfaces—Our First Generation 2181 kBytes gen1.pdf


PE Tech documentation

PE Tech system documentation

The digital I/O boards that were designed for PE Technikon for alternative energy research in 1988 were considered our “first generation” digital I/O cards. We had designed numerous “one-off” boards before that, however, these we manufactured in reasonable quantities and covered their development costs.

Generation 1 I/O cards

The two populated boards were described in the PDF download—the left hand is a 24Vdc contact closure monitoring card with power sourced (and current limited) by the card; the top middle card is the AC/DC monitoring card with the design inspired by Hewlett Packard’s HCPL-3700 application note1, the top layout is a double sided 68008 processor board with photographs in the download; and the bottom layout is a short SABUS backplane. The backplane was not shown in the PDF download, however, it was double sided with an interleaved ground screen (only one side shown here as a “doctored” Photoshop of the original scanned in image with some colour fills). The backplane was incredibly cheap when compared to Zilog’s ZBus and Vero Electronics’ VME backplanes. Vero and others had patented their strip-line and interleaved grounding, which we saw in brochures but while under sanctions, did not bother about further. We bought plenty of Vero VME backplanes later for Oettle & Riechler cards and PowerPC work.

1 Hewlett Packard (now Avago Technologies), “Threshold Sensing for Industrial Control Systems with the HCPL-3700 Interface Optocoupler”, Application Note 1004, not sure of the year but over 20 years ago. The new download was 5953-0406E, May 4, 2010.