RIO (Remote Input/Output) MICROPROCESSOR BOARD

The last two such control boards use Wizardry's RIO (Remote Input/Output), which was introduced in 1986.
The RIO delivers I/O ports to a remote (100 meters distance) location.
Communication is over a RS-485 (1-twisted-pair) communications interface, using a 4-conductor cable which also supplied the RIO's power (unregulated 24VDC).
The RIO was so usable that new systems incorporating it shipped as recently as 2004, and new replacement boards shipped as recently as 2008.

Since being introduced, the RIO's hardware design (based on the Intel 8096) was unchanged,
although the product was enhanced several times through software upgrades.

About 1550 units have been fabricated thus far.
About half the units ever made are running faithfully 24 hours/day.
Much of the balance is still installed in factories, waiting to be reactivated when business conditions to improve.

About $1 billion product/year is manufactured by machines controlled by this board at this time (2009).

Input/Output features:

RS-485 communications to/from control computer (1-twisted-pair).

32 logic-inputs.

32 logic-outputs.

8 A2D (Analog-to-Digital) inputs.

4 D2A (Digital-to-Analog) outputs
    & 4 corresponding duty-cyle outputs.

4 pulse-counting/tachometer (frequency-measuring) inputs.

4 communications-ID-number inputs.

All I/O is unpluggable.

Software features:

Efficient communications protocol (token-passing, 1 byte per token-pass).

EPROM-based firmware written in assembly-language.

Power-supply features:

Power using unregulated 24VDC.

Undervoltage detection & overvoltage crowbar on all power-supplies.

Multi-layer power-supply distribution, for reliable noise-free operation.

Maintenance features:

Easy field-maintenance is achieved through extensive use of socketed parts.

Through-hole construction means simple soldering repairs (no specialty surface-mount tools required).

Demonstrated field-lifetime exceeding 20 years.