Vega MET 381 Mise En Service page 24

6 Setup with the integrated display and adjustment unit
potential equalisation.
If potential equalisation currents are expected,
the screen connection on the side of VEGAMET
381 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.
Select 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.
5.2 Input mode active/passive
With the function switch you can changeover
between active and passive operation of the
measuring data input.
•
In active mode, VEGAMET 381 provides
the power for the connected sensors. Power
supply and measurement data are transmit-
ted over the same two-wire cable. This mode
is provided for connection of measuring
transducers without separate voltage supply
(sensors in two-wire version).
•
In passive mode the sensors are not powe-
red, only the measured value is transmitted.
This input is for connection of transmitters
with their own separate voltage supply (sen-
sors in four-wire version). The VEGAMET
381 can be also looped into the existing
circuit like a normal ammeter.
5.3 Connection procedure
Proceed as follows:
1. Mount VEGAMET 381
2. Connect sensor cable to terminal 1 and 2,
and where applicable, connect the screen
3. Connect power supply (switched off) to
terminal 5 and 6
4. If necessary, connect fail safe and operating
relay as well as current output
The electrical connection is finished.
24
5.4 Wiring plan
Overview
7
Abb. 13: Wiring plan with two-wire sensor
1 Measurement data input, optionally available with
sensor power supply
2 Current output
3 Fail safe relay
4 Relay 2
5 Relay 1
6 Voltage supply
Tipp:
For parameter adjustment of connec-
ted HART sensors, the sockets are
integrated in the terminals of the meas.
data input. A VEGACONNECT can be
directly plugged in without the need of
an additional HART resistor.
6 Setup with the integrated
display and adjustment
unit
6.1 Adjustment system
The integrated display and adjustment unit is
for measured value display, adjustment and
diagnosis ofVEGAMET 381. Indication and
adjustment is carried out in the front via a clear
LC-display and a function switch as well as two
keys.
To open the cover, insert a screwdriver in the
two slots on the top and turn it slightly.
VEGAMET 381 • 4 ... 20 mA signal conditioning instrument
+ - + -
1 2
1 2 3 4
1 2
%
18 17 16 15 14 13 12 11 10 9 8 7 6 5
N- L1+
3 4 5
1
2
on
6