Connecting To Power Supply; Preparing The Connection - Vega VEGABAR 17 Operating Instructions Manual

Note safety instructions
Take note of safety
instructions for Ex
applications
Select power supply
Select connection cable
Cable screening and
grounding
VEGABAR 17 •
5

Connecting to power supply

5.1

Preparing the connection

Always keep in mind the following safety instructions:
•
Connect only in the complete absence of line voltage
•
If overvoltage surges are expected, overvoltage arresters should
be installed.
Tip:
We recommend VEGA overvoltage arrester ÜSB 62-36G.X.
In hazardous areas you must take note of the respective regulations,
conformity and type approval certificates of the sensors and power
supply units.
The supply voltage and the current signal are carried on the same
two-wire connection cable.
Provide a reliable separation between the supply circuit and the
mains circuits according to DIN EN 61140 VDE 0140-1.
VEGA power supply units VEGATRENN 149AEx, VEGASTAB 690,
VEGADIS 371 as well as all VEGAMETs meet this requirement. When
using one of these instruments, protection class III is ensured for
VEGABAR 17.
Keep in mind the following additional factors that influence the operat-
ing voltage:
•
Output voltage of the power supply unit can be lower under nomi-
nal load (with a sensor current of 20.5 mA or 22 mA in case of fault
message)
•
Influence of additional instruments in the circuit (see load values in
chapter "Technical data")
The instrument is connected with standard two-wire cable without
screen. If electromagnetic interference is expected which is above the
test values of EN 61326 for industrial areas, screened cable should
be used.
Use cable with round cross-section. A suitable cable outer diameter
of (see chapter "Technical data") ensures the seal effect of the cable
gland. If you are using cable with a different diameter or cross-sec-
tion, exchange the seal or use a suitable cable gland.
For the version with round plug connector M12 x 1, a suitable, ready-
made connection cable (article no. ASL.1S.) in 5 m, 10 m or 25 m
lengths is available from the line of VEGA accessories.
If screened cable is required, connect the cable screen on both ends
to ground potential.
In Ex systems, the grounding is carried out according to the installa-
tion regulations.
In electroplating and CCP systems (cathodic corrosion protection) it
must be taken into account that significant potential differences exist.
5 Connecting to power supply
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