KROHNE OPTISOUND 3010 C, Handbook

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5 Connecting to power supply
OPTISOUND 3010 C • Four-wire 4 … 20 mA/HART
30504-EN-220310
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
Warning:
Connect only in the complete absence of line voltage.
•
The electrical connection must only be carried out by trained,
qualified personnel authorised by the plant operator.
•
If overvoltage surges are expected, overvoltage arresters should
be installed.
Note:
Install a disconnecting device for the instrument which is easy to
access. The disconnecting device must be marked for the instrument
(IEC/EN 61010).
Supply voltage and current output are carried on separate two-wire
connection cables if reliable separation is required. The supply volt-
age range can differ depending on the instrument version.
The data for power supply are specified in chapter "
Technical data ".
The standard version can be operated with an earth-connected cur-
rent 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.
Always connect the instrument to vessel ground (potential equalisa-
tion) or in case of plastic vessels to the next ground potential. For
this purpose there is a ground terminal on the side of the instrument
housing.
For voltage supply, an approved installation cable with PE conductor
is required.
The 4 … 20 mA current output is connected with standard two-wire
cable without shielding. If electromagnetic interference is expected
which is above the test values of EN 61326 for industrial areas,
shielded cable should be used.
Make sure that the cable used has the required temperature resist-
ance and fire safety for max. occurring ambient temperature
Use cable with round cross section for instruments with housing and
cable gland. To ensure the seal effect of the cable gland (IP protection
rating), find out which cable outer diameter the cable gland is suitable
for.
Use a cable gland fitting the cable diameter.
If shielded cable is required, we recommend connecting the cable
screening on both ends to ground potential. In the sensor, the cable
screening must be connected directly to the internal ground terminal.
Safety instructions
Voltage supply
Connection cable
Cable screening and
grounding