The Inputs
I/O Board Input and Output Setup • 11
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.
The exception to this rule is for CPC’s
5VDC pressure transducers
-- though they
supply their own voltage signal, the dip switch
MUST be set to the RIGHT (ON) position.
4.1.4. 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
for the location
of these points.
4.1.4.1.
Current Ratings for On-Board
Power Sources
The maximum current that may be drawn
from the +12VDC terminal is 100 milliamps.
The maximum current that can be drawn from
all three +5VDC terminals COMBINED is 50
milliamps.
4.1.4.2.
Powering Sensors Requiring
24VAC Off the Power Trans-
former
Some sensors that requires 24VAC can be
powered off the MultiFlex’s own 24VAC power
connection. To connect to the 24VAC power
source, connect the sensor’s power wires to ter-
minals AC1 and AC2.
This can only be done with sensors that keep
the 24VAC signal isolated from its DC output
signal (such as CPC’s Dew Point Probe). If the
output signal is not isolated from the 24VAC
input, you must use a separate transformer.
4.1.5. Sensor Types for MultiFlex
Input Points
Because different controllers may be com-
patible with different sensor types, this manual
cannot list all sensor types and how to wire them
to a MultiFlex input point. Refer to your site
controller’s documentation for sensor wiring
information.
Figure 4-2
- Input Board Power Sources
Summary of Contents for MultiFlex PAK
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