Det-Tronics C7050 A, C, G, P UV Flame Detector - Manual (Page 14)

IMPORTANT
Use only DE1888 sensor modules with the C7050
Detector. The jumper plug must not be installed on
the UV sensor module used with the R7404 Controller
(see Figure 12). The jumper plug is supplied for
detectors that are used with other controller models.
5. Using the index pin as a guide, install the sensor
module on the detector terminal block.
6. Re-assemble the detector housing. If the detectors
are equipped with cover locking devices, loosen the
clamp sufficiently so that the “catch” can be seated
in the blind hole provided on the terminal cap. (See
Figure 10.) The clamp must then be fastened
securely around the detector barrel by tightening
with the proper tool.
NOTE
If the wires from individual detectors are connected to
the R7404 Controller using a multiple conductor cable
with a single outer shield and without twisted pairs,
careful placement of the individual detector leads is
necessary to prevent “cross-talk” between zones.
The individual B-leads should be arranged around the
outside of the cable with a ground lead between. The
inner layer of conductors should be the D-leads and
the common A-lead should be in the center.
When using multiconductor cable with twisted pairs,
only one leadwire of each twisted pair can be con-
nected to the B-terminal in the detector. The other
leadwire must be used as a shield by connecting it
to the C-terminal in the detector and to ground ter-
minal 2 on the R7404. When several detectors are
connected to one controller using twisted pairs of
leadwires, a junction box is required to connect the
many ground leads together so that only one
ground leadwire need be run to the controller.
(Keep this common ground leadwire as short as
possible.) Ground all unused leads at the con-
troller. For additional information refer to Service
Memo 75-1003, “Multiconductor Cable Wiring.”
CONTROLLER
The controller is furnished with a field wiring connector
that incorporates pressure type screw terminals for
attaching wires and two circuit board edge connectors
for plugging in the controller.
The controller must be located in a non-hazardous area.
The use of a mounting cage is recommended for mount-
ing the controller. The cage is designed to hold the field
wiring connectors for ease in making electrical connec-
tions and installing, servicing, or replacing the modules.
The Q4004 Mounting Cage is designed to hold up to 8
modules in a 19 inch instrument rack (See Figure 5).
This mounting cage can also house voltage converters
or other equipment that is used in conjunction with the
R7404 as part of the total detection system. Cages that
hold fewer modules are also available. Optional filler
panels (part number 002188-001) are available for cov-
ering unused sections of the mounting cage.
NOTE
The R7404 Controller contains several semicon-
ductor devices that are susceptible to damage by
electrostatic discharge. An electrostatic charge can
build up on the skin and discharge when an object
is touched. Therefore, the controller should be
handled carefully, taking care not to touch the ter-
minals or electronic components. For more infor-
mation on proper handling of the controller, refer to
the Service Memo (form 75-1005)
Switch Setting Procedure
It is essential that the controller be properly pro-
grammed before applying power to the system.
There
are four rocker switch assemblies on the left side of the
controller. Each switch assembly has eight rockers,
which are opened or closed to select zone and detector
combinations, controller sensitivity, fire logic, output
latching, and time delay. Figure 13 illustrates the left
side of the R7404 and contains a short explanation of
rocker switch usage.
CAUTION
Use care when setting the rocker switches on the
controller. An incorrectly set rocker switch can
result in an obvious controller malfunction, or in
some cases the controller can appear to be func-
12
A0971
REMOVE JUMPER PLUG
Figure 12—Jumper Plug