VEGA VEGAPULS 45 4 … 20 mA; HART compact sensor - Manual (Page 36)

36 VEGAPULS 42, 44 and 45 – 4 … 20 mA
Electrical connection
2
- +
4 … 20mA
2
2
2
1)
4
Measuring system with VEGAPULS 42 or 44 in four-wire technology
• Four-wire technology, power supply and output signal via two separate two-wire cables.
• Output signal 4 … 20 mA active.
• Optional external indicating instrument with analogue and digital indication (can be mounted
up to 25 m away from the sensor).
• Adjustment with PC, HART ® handheld or adjustment module MINICOM (can be plugged into
the sensor or into the indicating instrument VEGADIS 50).
• max. resistance on the signal output (load) 500
Ω.
(active) 2)
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 of 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 would not be ensured.
HART ® handheld
VEGA-
CONNECT 2
≥ 250 Ω
2) 4 … 20 mA active means that the sensor delivers
a level-dependent current of 4 … 20 mA (source).
The sensor reacts electrically in the processing
system (e.g. indication) like a current source.