Instruction manual

AM16/32 Relay Analog Multiplexer
2
For a discussion of single-ended versus differential analog
measurements, please consult the Measurement section of your
datalogger manual.
As purchased, the AM16/32 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 AM-ENC
(10” X 12”) enclosure is recommended.
1.2 Compatibility
The AM16/32 is compatible with Campbell’s CR5000, CR1000, CR23X,
CR10(X), 21X, and CR7 dataloggers.
The AM16/32 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, CR23X, and CR10(X) applications the AM16/32 may be used to
multiplex up to 16 Geokon vibrating wire sensors through one AVW-1
vibrating wire interface.
2. Physical Description
The AM16/32 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 AM16/32’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 AM16/32 can be fastened to a flat surface or an enclosure plate (Section 8).
All connections to the AM16/32 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 AM16/32 are for sensor and sensor shield
connection (Section 4.2). The sensor inputs are not spark-gap protected. All
terminals accept stripped and tinned lead wires up to 16 AWG or 1.6 mm in
diameter. The datalogger-to-AM16/32 cabling requires a minimum of six and
as many as nine individually insulated wires with shields.
NOTE