Campbell Scientific AM16/32A Multiplexer - Manual (Page 41)

AM16/32A Relay Analog Multiplexer
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7. General Measurement Considerations
ths – Longer sensor-to-AM16/32A leads result in
duced and capacitively coupled voltages (cross-talk)
etween cable wires. To minimize capacitive effects CSI
recommends the use of cabling having Teflon, polyethylene, or
ould
ith PVC insulation around individual conductors
(PVC cable jacket is acceptable). It may also be necessary to program
within the measurement instruction allowing time for lead
wire capacitances to discharge after advancing a channel, before the
rement is made. Please consult the theory of operation section
of your datalogger manual for more information.
Ground – The AM16/32A o
earth ground via an 8 AWG wire. This connection should be as short
as possible. The AM16/32A also connects to earth ground via the
er. The lead wire that connects the datalogger power ground
32A power ground (“GND”) establishes this connection.
nance Section of your datalogger manual
ation on grounding procedures.
- In some applications it is advantageous to place
completion resistors at the datalogger terminal strips. Certain sensors
specific to the use of multiplexers are available from CSI. Examples
include soil moisture probes and thermistor probes. Please consult
ng and pricing information.
on - Once excitation in excess of 30 mA has been
, that channel’s relay contacts have been rendered
for further low voltage measurement. To prevent undue
gradation, it is advisable to reserve certain channels for sensor
and employ other channels for sensor signals.
8. Ins l a
rd AM16/32A may be operated in an indoor, non-
ronment. If condensing humidity is present or if the
ts that the multiplexer might be exposed to liquids, a
h CSI (models
/12, ENC 12/14, ENC 14/16, and ENC 16/18). They offer a
of protection against dust, spraying water, oil, falling dirt, or
dripping, noncorrosive liquids. These enclosures contain a mounting
Long lead leng
greater in
b
polypropylene insulation around individual conductors. You sh
not use cables w
a delay
measu
Earth ’s ground lug should be connected t
datalogg
to the AM16/
The Installation/Mainte
contains more inform
Completion resistors
CSI for orderi
Contact degradati
multiplexed
suitable un
de
excitation
ta l tion
The standa
condensing envi
possibility exis
water-resistant enclosure is required.
Several encl
10
osures are available for purchase throug
ENC
degree
35