VEGA Capacitive electrodes EK 4 … 20 mA - Compact - Manual (Page 29)

Capacitive electrodes EK 4 … 20 mA - Compact 29
22574-EN-020809
4.4 Adjustment with HART ®
handheld
The capacitive electrodes EK with oscillator
CAP E32 H Ex are HART
® protocol capable
and can be adjusted with a HART ® handheld.
All relevant sensor functions can be executed
with the HART
® standard menus. A manufac-
turer-specific DDD (Data-Device-Description)
is not necessary.
Connect the HART
® handheld to the sensor
signal cable after you have connected the
sensor to power supply.
Multidrop mode
The multidrop mode can be selected with the
HART
® handheld.
With this mode, several HART ® sensors can
be connected to a single two-wire cable.
Beside the 4 … 20 mA signal, the sensor also
delivers a digital (HART
® ) level signal.
• If you enter address 0 (factory setting), the
sensor consumes a level-dependent
4 … 20 mA current and delivers a digital
(HART
® ) level signal. It is also possible to
connect e.g. an indicating instrument
(4 … 20 mA) to this cable.
• If you enter an address between 1 and 15,
the sensor consumes a permanent 4 mA
current and delivers a digital (HART
® ) level
signal.
4 3 2 1
+ - + -
mA
250 Ohm
HART® handheld
Setup
Burst mode
Normally the sensor signals the measured
values to the processing unit only on request.
If you switch on the burst mode, the sensor
signals the measured value without being
requested.
Note
If the resistance of the power supply is less
than 250 Ohm, a resistor must be connected
to the signal/connection cable during adjust-
ment. Otherwise the adjustment and communi-
cation signals would be short-circuited by
insufficient resistance, e.g. of the supply cur-
rent source or the processing system, result-
ing in possible failure of sensor
communication. The easiest way is to connect
the adjustment resistance in parallel to the
connection socket of the HART
® handheld
(see fig. 1, page 36).
Connection to a VEGA signal conditioning
instrument
(fig. 3 on the next page)
If you operate a HART
® capable sensor on a
VEGA signal conditioning instrument, you
have to a connect a resistance (acc. to the
following table) to the sensor connection on
the signal conditioning instrument during the
HART
® adjustment.
VEGA signal conditioning instr. Rx
VEGAMET 513, 514, 515, 602
VEGATRENN 544
VEGATOR 521…527
50 … 100 Ohm
VEGAMET 614 no additional
VEGADIS 371 resistance
necessary
VEGAMET 601 200 … 250 Ohm
VEGASEL 643 150 … 200 Ohm
VEGAMET 513 S4, 514 S4
515 S4
100 … 150 Ohm