Det-Tronics EQP Fire and Gas Detection/Releasing System - Manual (Page 68)

3-49 14.1 95-8533
EQ22XXDCU DIGITAL COMMUNICATION UNIT
USED WITH POINTWATCH/DUCTWATCH
Determine the best mounting location for the detector.
Whenever practical, detectors should be placed
where they are easily accessible for calibration.
WARNING!
Do not apply power to the system with the cover
removed unless the area has been verified to be
free of combustible gases and vapors.
The DCU utilizes the following:
1. A terminal wiring board mounted at the bottom of
the junction box.
2. A communication module mounted above the
terminal wiring board using the standoffs
provided. See Figure 3-60.
Assembly and Wiring Procedure
Attach the PointWatch/DuctWatch to the DCU
enclosure. Do not over-tighten. If a sensor
separation kit is being used, attach the sensor to the
separation kit junction box and wire the device as
described in the “Sensor Separation” section.
Refer to the PointWatch instruction manual (form
number 95-8440) or the DuctWatch instruction manual
(form number 95-8573) for complete installation and
application information.
Refer to Figure 3-63 when wiring a PointWatch IR gas
detector and a DCU. The wiring code for PointWatch
is:
Red = + (24 vdc)
Black = – (common)
White = 4 to 20 ma signal
Yellow = Calibration input
Green = Chassis ground
Set the address for the device. Refer to “Setting
Device Network Addresses” for complete information
regarding the switch setting procedure.
Sensor Separation for DCU with PointWatch
Shielded four wire cable is recommended for
connecting the detector junction box to the DCU.
Cable with a foil shield is recommended. The shield
of the cable should be open at the detector junction
box and connected to earth ground at the DCU
junction box.
NOTE
To ensure proper operation, it is essential to
maintain a minimum of 18 vdc (including ripple)
at the PointWatch detector.
1
2
3
4
5
6
7
8
9
10
YELLOW
WHITE
BLACK
RED
GREEN
DCU POINTWATCH
14
13
12
11
–
–
+
+
24 VDC
POINTWATCH CALIBRATE
4 TO 20 MA IN
–
+
A
B
A
B
SENSOR POWER
COM 2
COM SHIELD
COM 1
A1876
Figure 3-63—PointWatch/DuctWatch Connected to DCU