VEGA VEGAPULS 54K enamel - Manual (Page 21)

VEGAPULS 54K enamel 21
24 101-EN-041227
4 … 20 mA
2
2
2
2
4
1)
Measuring system with VEGAPULS 54K on active PLC
• Two-wire technology, power supply from active PLC.
• Output signal 4 … 20 mA (passive).
• Measured value display integrated in the sensor.
• Optional external indicating instrument (can be mounted up to 25 m away from the sensor in
Ex area).
• Adjustment with PC, HART ® handheld or the adjustment module MINICOM (can be plugged
into the sensor or into the external indication instrument).
HART ® handheld
VEGA-
CONNECT 2
Electrical connection
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 process-
ing system. Digital communication with the PC
would not be ensured.
VEGADIS 50
passive 2)
PLC (active) 3)
2) 4 … 20 mA passive means that the sensor
consumes a level-dependent current of
4 … 20 mA. The sensor reacts electrically like a
varying resistor (consumer) to the PLC.
3) 4 … 20 mA active means that the PLC delivers a
level-dependent current of 4 … 20 mA. The PLC
reacts electrically like a current source.