Preparing The Connection - Vega VEGABAR 17 Operating Instructions Manual

5 Connecting to power supply
Note safety instructions
Take note of
safety instruc-
tions for Ex ap-
plications
Select power supply
Selecting connection
cable
12
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
l
If overvoltage surges are expected, overvoltage arresters should
l
be installed.
Tip:
We recommend VEGA overvoltage arrester 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.
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 VDE 0106 part 101.
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.
Bear in mind the following factors regarding supply voltage:
Output voltage of the power supply unit can be lower under
l
nominal 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
l
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 cable outer diameter of 5 ... 9 mm
(0.2 ... 0.35 in) ensures the seal effect of the cable gland. If you are
using cable with other diameter or cross-section, you have to
exchange the seal or use a suitable cable gland.
For the version with round plug connector M12 x 1, the suitable
confectioned connection cable (article no. ASL.1S.) is available from
the line of VEGA accessory with 5 m, 10 m or 25 m length.
VEGABAR 17