VEGA VEGAPULS 56K - Manual (Page 27)

VEGAPULS 56K 27
22915-EN-041227
2
4
4 ... 20 mA
+
1)
-
> 250
Ω
4.4 Configuration of measuring
systems
A measuring system consists of a sensor
with 4 … 20 mA signal output and a unit that
evaluates and further processes the level-
proportional current signal.
On the following pages, you will see a
number of instrument configurations, desig-
nated as "measuring systems“, some of
which are shown with signal processing
units.
Measuring systems in two-wire technol-
ogy:
• 4 … 20 mA shown without processing unit;
• 4 … 20 mA on active PLC;
• 4 … 20 mA on active PLC in Ex area (ia);
• 4 … 20 mA on passive PLC in Ex area (ia);
• 4 … 20 mA on passive PLC in Ex area (d);
• 4 … 20 mA on VEGADIS 371 Ex indicating
instrument;
Measuring systems in four-wire technol-
ogy:
• 4 … 20 mA shown without signal condition-
ing instrument
Measuring systems with VEGAPULS 56K
• Two-wire technology (loop powered), supply and output signal via one two-wire cable
• Optional external indicating instrument with analogue and digital display (can be mounted
up to 25 m away from the sensor).
• Adjustment with PC, HART ® handheld or the adjustment module MINICOM (can be plugged
into the sensor or into the external indicating instrument VEGADIS 50).
1) If the resistance of the processing
systems connected to the
4 … 20 mA signal output is less
than 200
Ω, a resistor must be
connected to the connection cable
during adjustment to get a loop
resistance of 250
Ω up to 350 Ω .
The digital adjustment signal would
otherwise be severely damped or
short-circuited due to insufficient
resistance of the connected
processing system. Digital
communication with the PC would
not be ensured.
VEGADIS 50
VEGA-
CONNECT2
Electrical connection