
ZENO
®
-3200 USER MANUAL
Coastal Environmental Systems (206) 682-6048
Page 241
13. ELECTRICAL
CONSIDERATIONS
Coastal Environmental Systems
ZENO
®
-3200 User Manual
13.1. THE ZENO
®
-3200 ENCLOSURE
The ZENO
®
-3200 enclosure is NOT watertight, moisture-resistant or
weatherproof!
If you plan to install the ZENO
®
-3200 outdoors, it must be sheltered to
protect it from condensation and weather.
13.2. GROUNDING
Proper grounding is required to minimize errors in sensor readings and to
protect the ZENO
®
-3200 from damage due to ESD
280
, lightning-induced
power surges, and other potential causes.
Without proper grounding, interfering signals can couple to your sensor circuits, resulting in errors much
greater than those due to thermal noise. These errors can be introduced as:
Noise induced from AC signals typically arises from mutual inductance
281
or capacitive coupling
282
between different parts of the same circuit or different circuits. Using twisted pairs for signal and
excitation leads greatly reduces noise created by mutual inductance. Capacitively coupled noise can
be reduced by using shielded wire, with the shield grounded to earth at one end only.
280
ESD stands for electrostatic discharge.
281
A varying current in a circuit will create a varying magnetic field surrounding the circuit. If a separate, nearby
circuit is unprotected, the varying magnetic field from the first circuit can induce noise current in the unprotected
circuit. This phenomenon is called inductive coupling or mutual inductance.
282
Capacitive coupling occurs when the varying voltage of one circuit affects the voltage level of a nearby
unprotected circuit because of the varying electric field created by the first circuit.
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