Connection Procedure - Vega VEGABAR 17 Operating Instructions Manual

Cable screening and
grounding
Select connec-
tion cable for Ex
applications
Connection via angle
plug connector
VEGABAR 17
Connect the cable screen on both ends to ground potential.
If potential equalisation currents are expected, the connection on the
processing side must be made via a ceramic capacitor (e. g. 1 nF,
1500 V). The low frequency potential equalisation currents are thus
suppressed, but the protective effect against high frequency interfer-
ence signals remains.
Warning:
Considerable potential differences exist inside galvanic plants as well
as vessels with cathodic corrosion protection. Very large equalisation
currents can flow through the cable screen when the screen is
grounded on both ends. To avoid this, the cable screen must be
connected to ground potential only on one end (inside the switching
cabinet) in such applications. The cable screen must not be
connected to the internal ground terminal in the sensor and the outer
ground terminal on the housing not to potential equalisation!
Information:
The metallic parts of the instrument (antenna, transmitter, concentric
tube, etc.) are conductively connected with the inner and outer ground
terminal on the housing. This connection exists either as a direct
metallic contact or via the shielding of the special connection cable on
instruments with external electronics. You can find specifications on
the potential connections within the instrument in chapter "Technical
data".
Take note of the corresponding installation regulations for Ex
applications.

5.2 Connection procedure

Proceed as follows:
Loosen the screw on the rear of the plug connector
1
Remove the plug connector and seal from VEGABAR 17
2
Remove the plug insert from the plug housing
3
5 Connecting to power supply
13