VEGA VEGASON 66 4 … 20 mA_HART four-wire - Manual (Page 24)

5 Connecting to voltage supply
5.1 Preparing the connection
Generally not the following safety instructions:
l
Connect only in the complete absence of line voltage
l
If overvoltage surges are expected, overvoltage arresters
should be installed
Tip:
We recommend VEGA overvoltage arresters FS-LB-I and ÜSB
62-36G.X.
In hazardous areas you should take note of the appropriate
regulations, conformity and type approval certificates of the
sensors and power supply units.
If reliable separation is required, power supply with mains
voltage and current output are transmitted via separate two-
wire connection cables. The supply voltage range can differ
depending on the instrument version. The exact range is
stated in the "Technical data" in the "Supplement".
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 VEGASON 66 to vessel ground (potential
euqalisation) 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 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. If strong electromagnetic interfer-
ence is expected, screened cable should be used.
An outer cable diameter of 5 … 9 mm ensures the seal effect
of the respective cable entry.
If screened cable is necessary, 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 on the outside of 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
24 VEGASON 66 - 4 ... 20 mA/HART - four-wire
Connecting to voltage supply
28783
-EN
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