Last update: 2021/04/27 20:10
safety:pass
https://wiki.pangolin.com/doku.php?id=safety:pass
https://wiki.pangolin.com/
Printed on 2022/07/28 09:15
optional laser output power and optional control panel signals, PASS, by itself, cannot ensure the safety
of a laser show. Divergence-modifying elements (such as the SafetyScan lens) are actually more critical
to audience safety than is PASS. This is because under normal circumstances, (i.e. when everything is
working properly and you are using proper divergence and show presentation techniques) PASS plays
only a secondary and passive role in audience scanning safety, whereas a divergence increasing lens and
proper show performance techniques play a primary and continuous role in audience scanning safety.
And although the PASS hardware has been designed to be self-testing and employs redundant circuitry, it
is ultimately an electronic circuit, and it is conceivable that, under certain rare circumstances, the PASS
circuitry could fail in such a way that it would not prevent an unsafe laser exposure. This is why the
Professional Audience Safety System is not considered to be only the PASS hardware circuit board by
itself, but rather an entire safety system, which includes the external light sensor, external shutter, and
projector interlock. It is only when all of these things are used together and properly adjusted, that there
will be sufficient redundancy and monitoring to reduce the risk of an unsafe laser exposure.
Of course the adjustments on PASS must be configured properly, for the scanning velocity and dwell time
as well as the projection horizon (if used). Moreover, the light-sensor-related adjustments on PASS must
be configured to monitor the minimum beam power of the laser (to ensure proper light sensor and laser
diode driver operation) as well as the maximum beam power of the laser (to ensure that exceeding a
safe power level will be detected by PASS).
And finally, it is clear that in order to ensure continued and repeated safe performance, tests of the entire
projection system must be conducted before each show performance (for example nightly), to make sure
all elements of the projector and computer system feeding the projector as well as the PASS hardware
itself are all working as expected. At a minimum, these tests should involve the projection of test
patterns specifically designed to demonstrate that PASS and other safety features are working properly
(both inside the audience area and outside), and that PASS will properly extinguish the laser beam when
needed, as well as properly disabling the projector (i.e.“tripping”) if the Maximum Beam Power is
exceeded. (Please contact Pangolin if you need assistance in the creation of such test patterns.)
The performance of these tests, along with any measurable analytical results should be logged, and the
log should be permanently kept in a safe place, so that it can be reviewed later if needed.
If any of the tests mentioned above provoke unexpected results, the projection system should not be
used for the laser show performance until the entire projection system has been examined and any
problem discovered has been remedied.
Board layout and Status LEDs