oi
FEATURE
Both sensors are equipped with the Optical Integrity
(
oi
) 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
oi
test
does not
produce an alarm condition.
The U7652 can be programmed (using a jumper
plug) for automatic and/or manually initiated
oi
test-
ing. Use of automatic
oi
is highly recommended.
Automatic
oi
With automatic
oi
selected, the
oi
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
oi
is selected, the detector
can also be tested using the manual
oi
test.
Manual
oi
The detector also incorporates a manual
oi
feature
that provides the same test as the automatic
oi
, and
in addition actuates the Alarm relay to verify output
operation. The manual
oi
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
oi
Test
On
On
Energized
Energized
During normal operation when automatic
oi
is selected, LEDs blink once
every 5 seconds. During normal operation when manual
oi
is selected, UV
and IR sides blink alternately every 5 seconds.
*Some earlier models will blink under these conditions.
