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PASS
Complete Help Docs - https://wiki.pangolin.com/
PASS Logic System monitor
The PASS circuitry is implemented almost entirely in analog circuitry. There are logic circuits within PASS,
but these logic circuits are entirely combinatorial in nature. This means that the logic is made up of
simple AND and OR statements, which can be easily understood by peers in the safety community. There
are no sequential-logic circuits within PASS, nor are there any microprocessors, which could not be fully
validated.
In addition to the logic used by PASS to implement the basic safety features, PASS also includes a
separate layer or logic that actually watches the first logic layer, and verifies sanity. If there is a problem
within the PASS logic, the color and intensity signals are blanked, the shutter is closed, and the projector
interlock signal path is opened. The system will remain in that state until power is recycled, or until a
Manual Reset is performed.
Layout and Connections
The general layout of PASS is shown above, with connectors identified.
Pangolin includes connectorized ribbon cables with PASS. These ribbon cables can be used directly,
allowing minimal effort to integrate PASS within a projector. When ribbon cables have a red stripe on one
side, the red stripe indicates the side of the cable associated with pin 1.
J801: Projector-Signal-Input
The Projector-Signal-Input to PASS may come directly from the DB- 25 input on the projector, or may
come after projector internal electronics that condition the color signals (for example, allow adjustment
of intensity for each color or scanner axis inversion and rotation). When PASS is used for direct projector