VEGA VEGAPULS 45 4 … 20 mA; HART compact sensor - Manual (Page 40)

40 VEGAPULS 42, 44 and 45 – 4 … 20 mA
Electrical connection
VEGAPULS 42 Ex or 44 Ex (loop powered) with pressure-tight encapsulated
connection compartment on active PLC (Ex d)
• Two-wire technology, supply via the cable from active PLC to Exd connection housing for
operation in Ex-Zone 1 (VEGAPULS …Ex) or Ex-Zone 0 (VEGAPULS …Ex0).
• Output signal 4 … 20 mA (passive).
• Measured value display integrated in the sensor.
• Optional external indicating instrument with analogue and digital display (can be mounted
up to 25 m away from the sensor in Ex area).
• Adjustment with PC, HART ® handheld or 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 250
Ω, a resistor must be connected to the
connection cable during adjustment to get a loop
resistance between 250
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 or the HART
® handheld would not be ensured.
2
4 … 20 mA
2
2
4
2
VEGA-
CONNECT 2
VEGADIS 50 Ex
passive 2)
Ex area Non Ex area
HART ®
handheld
PLC (active)
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.