Det-Tronics R7495D UV/IR Flame Detection System - Manual (Page 21)

When a gate length of 0.5 second or greater is used, the
programmed counts per gate value is multiplied by a fac-
tor that is determined by the gate length that has been
programmed using rocker switches 2-5 to 2-8. Refer to
Figure 22 to determine the proper multiplication factor.
Note that the multiplication factor is determined by the
highest numbered rocker switch in the closed position.
The STAR logic program uses this multiplication tech-
nique to prevent accidental programming of a very low
count value combined with a long gate length, since this
combination would result in an extremely high sensitivity
level that would increase susceptibility to false alarms.
For example, suppose that a gate length of 1.5 seconds
and a sensitivity of 4 counts per gate is selected. Since
the gate length exceeds 0.5 second, the counts per
gate value must be multiplied by the factor determined
from Figure 22. In this case, 4 counts per gate is multi-
plied by a factor of 4, to obtain a total programmed
value of 16 counts per gate. Without this feature, it
would be possible to program the system to interpret 4
counts in 1.5 seconds as a fire signal, which would
make the system susceptible to frequent false alarms.
Consecutive Gate Selection - Rocker Switches 3-5 to
3-8
These rockers select the number of consecutive gates
required for a fire signal. Consecutive gates are
selectable in 1-gate increments from 2 to 15 gates. If
fewer than 2 gates are selected (only rocker 5 closed),
the microprocessor will select 2. The values of the rock-
ers closed are added together. The typical consecutive
gate settings used in most applications are between 3
and 8 gates.
Rocker 3-5 - 1 Gate
Rocker 3-6 - 2 Gates
Rocker 3-7 - 4 Gates
Rocker 3-8 - 8 Gates
Detector Grouping - Rocker Switches 4-1 to 4-2
Rocker Switch 4-1
Closed = individual
Open = combined
Rocker Switch 4-2
Not used - leave open
Outputs Latching/Non-latching - Rocker Switch 4-5
Open = latching
Closed = non-latching
Once energized, an output will remain on (latching) until
the controller is reset if rocker 4-5 is set open.
Rocker Switch 4-6
Not used - leave open
When the proper position for each of the rocker switch-
es has been determined, record this information careful-
ly on the system layout chart in Figure 23. This provides
a means of double checking switch positions before
power is applied to the controller, and to provide a
record of switch positions for future reference.
TYPICAL SYSTEM APPLICATION
The following application is an example only. For assis-
tance in adapting a system to your individual require-
ments, contact the Field Support Group at Detector
Electronics.
Figure 14 illustrates the standard method of connecting
detectors to the controller. All cable shields are tied
together and connected to circuit ground, terminal 33.
A switch (normally open) can be connected between
terminals 31 and 32 to perform a system reset from a
remote location.
The following examples show all relay contacts in the
normal operating condition after the system is reset. To
reset the system, switch the faceplate toggle switch
from NORMAL to TEST and back to NORMAL, or press
the RESET/LAMP TEST pushbutton.
21 95-8331
START
ROCKER 2–8
CLOSED?
ROCKER 2–7
CLOSED?
ROCKER 2–6
CLOSED?
ROCKER 2–5
CLOSED?
YES
YES
YES
YES
MULTIPLY BY 16
MULTIPLY BY 8
MULTIPLY BY 4
MULTIPLY BY 2
A974
NO
NO
NO
Figure 22—Multiplication Factors