Campbell Scientific CS420 and CS425 PDCR 1830-8388 Pressure Transducer - Manual (Page 19)

CS420-L and CS425-L Pressure Transducers
8. Using Multiplexers
Multiplexers increase the number of transducers a single datalogger can
measure.
The CR500 and CR510 dataloggers do not support the use of
multiplexers. NOTE
8.1 Examples
The dataloggers in the examples measure four Druck pressure transducers that
are connected to an AM16/32A multiplexer. Excitation is supplied to the
sensor from the datalogger wiring panel. In the examples, excitation voltage
and ground connection to the sensor bypass the multiplexer and are applied
directly from the datalogger to the sensor.
This configuration allows up to 16 pressure transducers to be measured using a
single datalogger. Because the 5000 mV excitation exceeds the 21X’s drive
current, the 21X requires two loops that measure eight sensors each.
These examples require a pressure transducer with a minimum
impedance of 2K. Most Druck pressure transducers meet this
requirement. However, you can verify the transducer’s
impedance by reading across the red and white wire with an ohm
meter. NOTE
8.1.1 Wiring For One Druck Multiplexer/Datalogger
Multiplexer CS420-L/CS425-L Datalogger
SENSOR #1:
H1 (1)
Orange (Monitor +)
L1 (1) Black (Monitor -)
H2 (1) Yellow (Output +)
L2 (1) Blue (Output -)
Shield Clear (Shield)
Red (Excitation Voltage) E1
White (Supply G.) AG
Sensors #2, #3, and #4 are wired similarly to the multiplexer in sequential
input terminals. All red and white sensor wires bypass the multiplexer and
connect to the datalogger’s E1 and G respectively.
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