Blizzard Enclosure User Manual
page 40
DEC3 Control – Introduction
Tempest Lighting and Projector Enclosures have been in daily use around the world for almost a
decade. Tempest enclosures protect expensive and delicate equipment in all climates, maintaining
a comfortable operating temperature, and preventing condensation – the real outdoor enemy.
DEC3
TM
– that’s
Digital Enclosure Control, third Generation
– is the brain of your Tempest
enclosure. It will maintain the internal environment in a comfortable temperature and humidity
range, and prevent condensation – the real equipment killer. DEC3 monitors internal temperature,
humidity and lamp current at all times, and uses this information to control its lamp relay, fan(s)
and heater(s). It can report back over the DMX cable, using the RDM protocol (Remote Device
Management) if desired.
Unless otherwise specified, this version of the user guide refers to DEC3 units fitted with software version 2.1
or later.
So, what does DEC3 actually DO?
DEC3 is the brains of the operation – here’s a layout:
DEC3’s mission is to maintain temperature and humidity inside the enclosure, within determined
bounds, and to prevent condensation – particularly overnight dew formation – inside the
equipment housed. Condensation is fatal to electronic equipment, particularly in polluted areas or
saline environments, where it brings not only rust and short-circuits, but also a steady buildup of
mineral and/or salt deposits. Incidentally, condensation is very hard to control with air-
conditioning type systems, which is why we don’t use them.
Broadly speaking, DEC3’s function depends on whether the fixture/projector lamp is on or off:
Lamp
Heater
Fan
Relay
On
DMX
Temp
ESC
OK
Lamp
Current
Sensor
2
-
pole 25amp
240V lamp relay
40amp Fan switch triac
40amp Heater switch triac
Temperature Sensor
Humidity Sensor
DMX/RDM Input
Power
Supply
Controller
User Interface
DMX/RDM
Passthrough
to next DEC3
enclosure
DMX/RDM
Passthrough
to Projector (optional)
This schematic
shows the
relationship between
DEC3’s functional
elements.
The power supply is
universal 90-260V,
but fans and heaters
are either 120V or
230VAC, and must
be so specified.
A high-quality
25amp 2-pole
electro-mechanical
relay isolates
fixture/projector
power in the event of
an over-temperature
condition.
Fans and heaters are
switched using
generously overrated
40amp Triac devices
for maximum
reliability.
Two DMX outputs
connect to the
internal fixture (if
desired) and on to
other enclosures or
DMX devices.
