Campbell Scientific AM16/32B Relay Multiplexer - Manual (Page 36)

AM16/32B Relay Analog Multiplexer
Multiplexer to Datalogger Wiring — The two pairs of COM terminals (ODD
H, ODD L and EVEN H, EVEN L) are connected to two pairs of differential
analog inputs at the datalogger. Observe H to H and L to L from sensor to
multiple
be measu
With pan set to “2x32” mode, one differential input can measure up to
32 differential sensors in SETs of two with appropriate programming.
6.3 Half Bridge Mea
Measure
completi
nce and the presence or absence of measured excitation. If
the sensor’s completion resistor(s) are installed at the datalogger panel
ampl en
E
6-
potentio
ed.
Because ound may be multiplexed in common, up to two
sensors per SET may be measured (FIGURE 6-4). If measured excitation is
required (as in four wire half-bridge), then only one sensor per SET of four
may be measured (FIGURE 6-5).
6.3.1 Half Bridge Measurement with Completion Resistor at Datalogger
Sensor to Multiplexer Wiring — Up to three half bridges may be connected to
one input SET in “4x16” mode, provided the sensors’ three completion
resistors are located at the datalogger (FIGURE 6-3).
Multiplex gger Wiring — Signal lines from the multiplexer COM
terminals tie to three consecutive single-ended analog input channels. Three
precision completion resistors connect from analog input channels to analog
ground i
xer to analog input. In “4x16” mode up to 32 differential sensors can
red by two differential datalogger channels in this way.
el switch
surements
ments of this type may be subdivided into three categories based on
on resista
(ex
thre e: a Campbell Scientific 107 probe modified for multiplexer use), th
bes per SET may be excited and measured in “4x16” mode ( e pro
3). Ho
FIGUR
wever, if the circuit is completed within the sensor (for example,
meters), then excitation, wiper signal, and ground must be multiplex
excitation and gr
er to Datalo
n CR10(X) or to “ ” in the other dataloggers.
/
0
"4 X 16" Mode
COM H (ODD)
COM L
COM H (EVEN)
COM L
ODD H
ODD L
EVEN H
EVEN L
SHIELD SENSOR SHIELDS COM
MUXSIGNAL
SHIELD
CR23X/
CR800/
CR850/
CR1000
21X/
CR7 CR10(X)
CR3000/
CR5000
EX E E VX
H H H H
L L L L
H H H H
AG
G
6-3. Half bridge (modified 107 Temperature Probe) hookup
measurement
FIGURE
and
CABLE5CBL
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