Campbell AM16/32, Instruction Manual

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AM16/32 Relay Analog Multiplexer
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same composition as the high side of the thermocouples. Also, the
wire that connects COM EVEN L to datalogger ground should be of
the same composition as the low side of the thermocouples.
If the reference junction is at the AM16/32 (CSI 107 thermistor, RTD,
etc.), then copper wire should be used to connect COM terminals to
the datalogger.
6.6.3 Differential Thermocouple Measurement
AM16/32 panel switch set to “4X16” mode.
Sensor to Multiplexer wiring - up to two thermocouples per input
SET.
Multiplexer to Datalogger wiring - The wire types here can be
handled in one of two ways. If a reference junction (107 thermistor, or
RTD, etc.) is at the AM16/32, then two pairs of copper wires may be
run between the COM terminals of the multiplexer and two differential
input channels.
If the reference junction is at the datalogger, then two pairs of
thermocouple wire should be run between the COM terminals of the
multiplexer and the two differential input channels (observe TC wire
polarity).
6.7 Mixed Sensor Types
In applications where sensor types are mixed, multiple hook-up
configurations and programming sequences are possible. Please
consult CSI for application assistance if you need to multiplex
markedly different sensor types in your application.
6.7.1 Mixed Sensor Example: Soil Moisture Blocks and
Thermocouples
AM16/32 panel switch set to “4X16” mode.
In this example, 16 thermocouples and 16 soil moisture blocks will be
multiplexed through the AM16/32. One thermocouple and one soil
moisture block are input into each SET.