VEGA VEGAPULS 51K…54K 4 … 20 mA; HART compact sensor - Manual (Page 48)

48 VEGAPULS 51K … 54K
21750-EN-031222
Connection to a VEGA signal conditioning
instrument
If you operate a HART ® compatible sensor on
a VEGA signal conditioning instrument, you
have to connect the sensor via a resistor
(see following table) during HART
® adjust-
ment. This resistor, together with the internal
resistance of the instruments, provides the
value of 250 Ohm required for the HART
®
instrument. An inherent system load resist-
ance allows a corresponding reduction of Rx.
VEGA signal conditioning instr. Rx
VEGAMET 513, 514, 515, 602 50 … 100 Ohm
VEGAMET 614 no additional
VEGADIS 371 resistor
required
VEGAMET 601 200 … 250 Ohm
VEGASEL 643 150 … 200 Ohm
VEGAMET 513 S4, 514 S4
515 S4, VEGALOG EA card
100 … 150 Ohm
Set-up
Just connect the HART ® handheld to the
signal cable, after having connected the
sensor to power supply.
Note:
If the resistance of the power supply is less
than 250 Ohm, a resistor must be connected
into the signal/connection loop during adjust-
ment.
The digital adjustment and communication
signals would otherwise be short-circuited
due to insufficient resistance of the supply
current source or the processing system,
and as a result, communication with the sen-
sor would not be ensured.
Ri > 250
Ω
+
-
250
Ω
Ri < 250 Ω
+
-
With any HART ® handheld you can set up the
VEGAPULS series 50K radar sensors like all
other HART
® compatible sensors. A special
DDD (Data Device Description) is not neces-
sary.
5.4 Adjustment with HART ® handheld