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.
Refer to Table VI-1 to determine the maximum allowable
wiring from the PointWatch to the power supply (through
the DCU).
NOTE
To ensure proper operation, it is essential to
maintain a minimum of 18 vdc (including ripple) at
the PointWatch detector.
EQ2200DCUEX DIGITAL COMMUNICATION UNIT
USED WITH DET-TRONICS COMBUSTIBLE GAS
SENSORS
Determine the best mounting locations for the detectors.
Whenever practical, detectors should be placed where
they are easily accessible for calibration. Always orient
the junction box with the sensor pointing down.
WARNING
Do not apply power to the system with the cover
removed unless the area has been verified to be
free of combustible gases or vapors.
The DCUEX uses the following:
1.
The terminal wiring board is mounted at the bottom
of the junction box.
2.
The transmitter board is mounted above the
terminal wiring board.
3.
The communication module is mounted above the
transmitter board.
The boards are connected to each other using the
standoffs provided. See Figure VII-37.
NOTE
Be sure to note correct orientation of the
transmitter board. If the transmitter board is
rotated 180° from proper orientation, the device
will not operate correctly — a LON
communication fault will result. See Figure VII-
37.
Assembly and Wiring Procedure
Connect the external wiring to the appropriate terminals
on the DCU terminal wiring board. See Figure VII-38.
Attach the sensor 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 below.
VII-24
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 VII–36—PointWatch Connected to DCU
Содержание Eagle Quantum 95-8470-05
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Страница 128: ...LON is a registered trademark of Echelon Corporation Modbus is a registered trademark of Modicon Inc...