Campbell Scientific AM16/32A Multiplexer - Manual (Page 8)

AM16/32A Relay Analog Multiplexer
For a discussion of single-ended versus differential analog
measurements, please consult the Measurement section of your
datalogger manual. NOTE
As purchased, the AM16/32A is intended for use in indoor, non-condensing
environments. An enclosure is required for field or high humidity use. In
applications where one or two multiplexers are deployed, the ENC 10/12
(10” x 12”) enclosure is recommended.
1.2 Compatibility
The AM16/32A is compatible with Campbell’s CR5000, CR800, CR850,
CR3000, CR1000, CR23X, CR10(X), 21X, and CR7 dataloggers.
The AM16/32A is compatible with a wide variety of commercially available
sensors. As long as relay contact current maximums are not exceeded (see
Cautionary Notes, page iii), and no more than four lines are switched at a time,
system compatibility for a specific sensor is determined by sensor-datalogger
compatibility.
In CR1000, CR800, CR850, CR3000, CR23X, and CR10(X) applications the
AM16/32A may be used to multiplex up to 16 Geokon vibrating wire sensors
through one AVW1 vibrating wire interface.
2. Physical Description
The AM16/32A is housed in a 10.2 cm x 23.9 cm x 4.6 cm (4.0” x 9.4” x 1.8”)
anodized aluminum case (Figure 1). The aluminum case is intended to reduce
temperature gradients across the AM16/32A’s terminal strips. An aluminum
cover plate is also included to this end. This is extremely important if
thermocouples are being multiplexed (Section 6.6).
The case can be opened for inspection/cleaning by removing two phillips-head
screws located on the under-side of the case. Mounting tabs are provided so
the AM16/32A can be fastened to a flat surface or an enclosure plate (Section
8).
All connections to the AM16/32A are made on the top panel terminal blocks.
The island of four terminals located near the mode switch are dedicated to the
connecting of datalogger power and control lines (Section 4.1). The four
“ODD” and “EVEN” “COM” terminals on the other side of the mode switch
carry shielded multiplexed sensor signals destined for datalogger analog
inputs. The remaining terminals on the AM16/32A are for sensor and sensor
shield connection (Section 4.2). All of the inputs of the AM16/32A are
protected with gas tubes. The terminals accept stripped and tinned lead wires
up to 16 AWG or 1.6 mm in diameter. Datalogger-to-AM16/32A cabling
requires a minimum of six and as many as nine individually insulated wires
with shields.
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