Delphin ProfiMessage, Руководство по оборудованию

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Profi Message
Connect the PE terminal with a ≥ 2.5mm2 cable to the protective earth of your
power supply.
Refer also to Shielding , Galvanic isolation .
7.3 Earth loops
By linking sensor, measurement device, and computer, connections then exist
between different ground points. Unless the individual devices are connected to
protective earth, this electro conductive connection creates an electrical circuit
between the devices. The result is what is known as an earth or ground loop
(shown red in the example).
This can have the following effects:
l
In practice the earthing points U1 to U3 shown in the graph do not neces-
sarily possess equal potential. Constant or changing potential differences
can occur between the earthing points due to the earthing plan and wiring.
Compensating currents then occur in the sensor and communication cir-
cuits.
l
Interference in the sensor or communication circuits, for example through
electromagnetic fields, enable parasitic currents to occur within the circuit.
Compensation and parasitic currents lead to interference or noise voltage at the
input of the measuring instrument and thus constant or shifting errors in meas-
urement.
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Delphin Technology AG
Dezember 2015
Profi Message Manual