o
i
FEATURE
Both sensors are equipped with the Optical Integrity
(o
i
) test feature to assure proper operation of the
detector by checking the cleanliness of the optical
surfaces, sensitivity of the sensors, and proper func-
tioning of the electronic circuitry. No testing with an
external test lamp is required. The detector automati-
cally performs the same test that a maintenance per-
son with a test lamp would perform — once every
minute, 60 times per hour. A successful automatic o
i
test does not produce an alarm condition.
The U7652 can be programmed (using a jumper
plug) for automatic and/or manually initiated o
i
test-
ing. Use of automatic o
i
is highly recommended.
Automatic o
i
With automatic o
i
selected, the o
i
test is automatical-
ly performed on each sensor once every minute. If a
fault is detected, the normally energized Fault relay is
de-energized and the LEDs on the faulty sensor stop
blinking. When automatic o
i
is selected, the detector
can also be tested using the manual o
i
test.
Manual o
i
The detector also incorporates a manual o
i
feature
that provides the same test as the automatic o
i
, and
in addition actuates the Alarm relay to verify output
operation. The manual o
i
feature is available in all
models and can be performed at any time. This test
requires bypass of all extinguishing devices to
avoid release resulting from a successful test.
RELAYS AND OUTPUTS
All U7652 Models
All U7652 Models are furnished with two standard
output relays that are rated for 5 amperes (resistive)
at 30 vdc.
Fire relay has SPDT (normally open/normally closed)
contacts:
— Normally de-energized (no fire).
— Energizes upon detection of fire.
— Field programmable for either latching or non-
latching operation.
Fault relay has SPST (normally open) contacts:
— Normally energized (no fault).
— De-energizes when fault is detected.
— Non-latching operation (automatically resets when
fault is corrected).
U7652C Model
The U7652C is furnished with either an auxiliary relay
or a 4 to 20 ma output in addition to the standard out-
puts. The U7652C with auxiliary relay requires the
presence of radiation at only one sensor for relay
actuation-rated for 1 ampere at 30 vdc. (Not recom-
mended for uncontrolled locations.)
Auxiliary relay has SPST (normally open) contacts.
— Field selectable for actuation when “UV radiation
only” or “any UV or IR radiation” is detected.
(Factory-shipped with the field selectable jumper
plug in the “UV only” position.)
— Normally de-energized (selected radiation not
detected).
— Energizes upon detection of selected radiation.
— Non-latching when responding to UV only or IR
only condition.
— Latches in response to UV and IR radiation at
background levels (fire threshold not exceeded).
Table 1—Detector Status Chart
2
Status UV LEDs IR LEDs Fire Relay Fault Relay
Normal Blinking Blinking De-energized Energized
UV Fault Off Blinking De-energized De-energized
IR Fault Blinking Off De-energized De-energized
General Fault Off Off De-energized De-energized
Background UV On Off* De-energized Energized
Background IR Off* On De-energized Energized
Fire On On Energized Energized
Manual o
i
Test On On Energized Energized
During normal operation when automatic o
i
is selected, LEDs blink once
every 5 seconds. During normal operation when manual o
i
is selected, UV
and IR sides blink alternately every 5 seconds.
*Some earlier models will blink under these conditions.
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