Det-Tronics U7602E Unitized UV Flame Detector/Controller - Manual (Page 10)

8
Different combinations of these variables
allow for various levels of transient arc
rejection capability. There are four arc
rejection levels (very high, high, medium,
and low) that are selectable for each
detector (SW- 6 and 7). Refer to Table 2.
The proper arc rejection setting for a given
application must be determined through
testing. For indoor applications with known
electrostatic energy fields within 15 feet of
the detector, an arc rejection setting of
“very high” or “high” is typical. For
outdoor applications, “medium” or “low”
arc rejection settings are typical.
It is recommended that each detector be
thoroughly tested at the programmed arc
rejection setting within the ambient
conditions that will be present during
normal operation. This will help to ensure
that the selected arc rejection setting is
proper for the application.
Close SW-1 to select arc rejection logic.
Place SW-1 in the open position for
standard fire detection.
SW-2 Automatic or Manual oi
The oi system uses an internally
generated UV test signal to determine the
relative condition of the detector and its
optical surfaces.
If automatic oi testing is selected, the oi
test is automatically performed once
every minute. The automatic
oi test does
not actuate the alarm relay or interfere
with normal detector operation.
The manual oi test is initiated using an
externally wired switch. A successful
manual
oi test activates the alarm relay
and current loop. The manual oi test can
be used in addition to automatic oi to
verify operation of the fire relay, LEDs and
field wiring.
Close switch to turn off automatic oi.
SW-3 Fire Relay Latching
When latching operation is selected, the
fire relay is reset by removing input power
for a minimum of 0.1 second.
SW-4 Fault Relay Latching
If the fault relay is set for latching, the fault
will not clear until it is corrected and the
unit is reset. If a fire occurs, the unit will
indicate a fire, over-riding the fault
condition. If a fault is still present after the
fire has been extinguished, the unit will
again indicate a fault until the problem
has been corrected and the unit is reset.
SW-5 Not used
SW-6,7 Select Level of Arc Rejection
(SW-1 closed)
The “very high” and “high” levels are
typically used in indoor applications. The
“medium” and “low” levels are typically
used in outdoor applications. These
switches have no effect when standard
signal processing is selected.
SW-8,9 Sensitivity
These switches affect the sensitivity of the
detector in both standard and arc rejection
modes. The selected sensitivity level
determines the fire alarm threshold
setpoint. The higher the sensitivity level,
the greater the detection range, but the
possibility of false alarms will be increased.
Four sensitivity levels are selectable. The
sensitivity setting must be appropriate for
the anticipated fire size at the required
distance from the detector.
SW-10 to 12 Time Delay
Standard Mode
The fire relay is actuated only if the fire
signal exceeds the sensitivity setting for
the entire duration of the programmed
time delay.
Arc Rejection Mode
If the fire signal meets the programmed
arc rejection requirements, the time delay
begins. The fire relay is actuated if the
fire signal continues for the duration of the
time delay.
NOTE
If the switch settings are ever changed, power to
the unit must be cycled before those changes will
take effect.