KROHNE OPTIBAR DP 7060 C EN - Manual (Page 39)

ELECTRICAL CONNECTIONS
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OPTIBAR DP 7060 C
www.krohne.com 04/2014 - 4003292001 - MA OPTIBAR DP 7060 C R01 en
4.4 Grounding the measuring device
If a shielded cable is necessary, connect the cable shield on both ends to the grounding potential.
In the signal converter, the cable shield must be connected directly to the internal ground
terminal. The ground terminal outside on the housing must be connected to the equipotential
bonding with low impedance. If equipotential bonding currents are expected, the evaluation side
must be connected with a ceramic capacitor (e.g. 1 nF, 1500 V). The low frequency equipotential
bonding currents are thus suppressed, but the protective effect against high frequency
interference signals remains.
4.5 Description of the current output
The current output is a 2-wire 4…20 mA output with a low alarm of 3.6 mA and high alarm of
21 mA set by default. A high frequency HART
® signal superimposes this signal. For further
information on the current output, refer to Technical data on page 63.
WARNING!
Within galvanic plants as well as vessels with cathodic corrosion protection there are
considerable potential differences. Considerably equipotential bonding currents can be caused
via the cable shield when the shield is grounded on both ends. To avoid this, the cable shield
must only be connected to the grounding potential on one side of the control cabinet in such
applications. The cable shield must not be connected to the internal ground terminal in the
device and the outer ground terminal on the housing not to the equipotential bonding!
CAUTION!
The metallic and wetted parts (process connection, cap flange, measuring cell and separating
diaphragm etc) are conductive connected with the inner and outer ground terminal on the
housing.
.book Page 39 Friday, May 2, 2014 10:25 AM