5 connecting to power supply, 1 preparing the connection – KROHNE OPTISOUND 3040 C 4wire EN User Manual

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5 Connecting to power supply

5.1 Preparing the connection

Always observe the following safety instructions:

Connect only in the complete absence of line voltage

If overvoltages are expected, overvoltage arresters should

be installed.

In hazardous areas you should take note of the appropriate

regulations, conformity and type approval certiﬁcates of the

sensors and power supply units.

Power supply and current output are transmitted via separate

two-wire connection cables. The power supply range can diﬀer

depending on the instrument version. The exact range is

stated in the "Technical data" in the Supplement.
The standard version can be operated with an earth-

connected current output, the Exd version must be operated

with a ﬂoating output.
This instrument is designed in protection class I. To maintain

this protection class, it is absolutely necessary that the ground

conductor be connected to the internal ground terminal. Take

note of the general installation regulations.
As a rule, connect OPTISOUND 3040 C to vessel ground

(potential equalisation), or in case of plastic vessels, to the

next ground potential. There is a ground terminal on the side of

the instrument housing.

For power supply, an approved installation cable with PE

conductor is necessary.
The 4 ... 20 mA current output is connected with standard two-

wire cable without screen. An outer cable diameter of 5 ...

9 mm ensures the seal eﬀect of the cable entry. If electro-

magnetic interference is expected, we recommend the use of

screened cable.

Connect the cable screen on both ends to ground potential. In

the sensor, the screen must be connected directly to the

internal ground terminal. The ground terminal outside on the

housing must be connected to the potential equalisation (low

impedance).

Note safety instructions

Take note of safety

instructions for Ex

applications

Select power supply

Selecting the connection ca-

ble

Cable screening and ground-

ing

OPTISOUND 3040 C - 4 ... 20 mA/HART - four-wire

Connecting to power supply

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