Connecting To Power Supply; Preparing The Connection - Vega VEGAMET 381 Ex Manual De Instrucciones

Abb. 12: Screw mounting
1 Metal strap
2 Covering slide switch active-passive
Carrier rail mounting
1. Place the adapter plate [1] to the rear of
VEGAMET 381 Ex (spring of the adapter
plate downward) and fasten the plate with
screw [2] (M4 x 6).
2. PlaceVEGAMET 381 Ex against the carrier
rail [3] from below and push the instrument
upward until it snaps in.
Abb. 13: Carrier rail mounting
1 Adapter plate
2 Screw (M4 x 6)
3 Carrier rail
5 Connecting to power
supply
5.1

Preparing the connection

Safety instructions
Always keep in mind the following safety inst-
ructions:
Warning:
Connect only in the complete absence
of line voltage.
•
Connect only in the complete absence of
line voltage
•
If overvoltage surges are expected, overvol-
tage arresters should be installed
Note:
Install a separating facility for the
VEGAMET 381 Ex • 4 ... 20 mA signal conditioning instrument
1
80
1 2 3
instrument which is easy to access. The
separating facility must be marked for
the instrument (IEC/EN 61010).
2
Safety instructions for Ex applications
In hazardous areas you must take note
of the respective regulations, conformity
and type approval certificates of the
sensors and power supply units.
Voltage supply
The power supply can be 20 ... 253 V AC,
50/60 Hz or 20 ... 253 V DC.
Connection cable
The voltage supply of VEGAMET 381 Ex is
connected with standard cable according to the
national installation standards.
The instrument is connected with standard
two-wire cable without screen. If electromag-
netic interference is expected which is above
the test values of EN 61326 for industrial areas,
screened cable should be used.
Make sure that the cable used has the required
temperature resistance and fire safety for max.
occurring ambient temperature
Cable screening and grounding
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
sensor housing must be connected to the
potential equalisation.
If potential equalisation currents are expected,
the screen connection on the side of VEGAMET
381 Ex must be made via a ceramic capacitor
(e. g. 1 nF, 1500 V). The low frequency potential
equalisation currents are thus suppressed, but
the protective effect against high frequency
interference signals remains.
Connection cable for Ex applications
Take note of the corresponding instal-
lation regulations for Ex applications. In
particular, make sure that no potential
equalisation currents flow over the cable
screen. In case of grounding on both
sides this can be achieved by the use
of a capacitor or a separate potential
equalisation.

5 Connecting to power supply

25