Emerson MultiFlex RTU, Installation And Operation Manual

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12 • MultiFlex RTU Operator’s Guide 026-1706 Rev 3
All Analog Temperature Sensors and Air Flow
Sensors
Temperature and air flow sensors are to be wired
with shielded, 2 conductor, at least 22 GA wire
(Belden # 8761 or equivalent).
All Pressure Transducers, Humidity Sensors, and
Refrigeration Transducers
Pressure and refrigeration transducers and
humidity sensors are to be wired with shielded, 3
conductor, at least 22 GA wire (Belden #8771 or
equivalent).
Dew Point and Light Level Sensors
These sensors are to be wired with shielded, 4
conductor at least 22 GA wire (Belden # 8729 or
equivalent).
4.1.3.3. Input Type Dip Switches
Each MultiFlex input point has an input type dip
switch that must be set. The input type dip
switches for the RTU are on the switch bank
labeled S1.
The input type dip switch tells the input board
whether or not the sensor connected to the point
is a resistive type sensor. Generally, if the sensor
or transducer supplies its own voltage signal to
the point, the dip switch should be set to the
LEFT (OFF) position. If the sensor uses variable
resistance and requires voltage to be supplied to
it from the input point, set the dip switch to the
RIGHT (ON) position. Dip switches for unused
points should be set to the RIGHT (ON)
position.
4.1.4. Input Connection When
Replacing ARTC with RTU
If the RTU you are installing is replacing an
existing ARTC, you will not be able to simply
unplug the input connectors from the ARTC and
plug them into the RTU. Doing so will cause the
inputs to be reversed and the polarity to be
swapped.
You must either re-wire each input to the proper
place on the RTU board, or obtain a Multiflex
input adapter cable (
P/N 335-2301),
as shown in
Figure 4-4 . Plug the connector with the probe
wires attached into the female end of the adapter,
and plug the male end into the RTU input socket.
4.1.5. On-Board Power Connection
If power is needed to operate the sensor, four
points are provided on the MultiFlex board that
supply DC power: one +12VDC point, and three
+5VDC points. See Figure 4-5 for the location
of these points.
Figure 4-3 - Input Type Dip Switches for RTU Board
(ON)
(OFF)
Figure 4-4 - MultiFlex Input Adapter Cable
Figure 4-5
- Input Board Power Sources
RIBBON CABLE
(P/N 335-2301)
FEMALE END (PLUG INPUT
CONNECTOR FROM OLD
BOARD HERE)
MALE END (PLUG INTO
MULTIFLEX
INPUT SOCKET)
POINT #1
POINT #2
POINT #3
POINT #4
POINT #1
POINT #2
POINT #3
POINT #4
+5 VDC
+12 VDC