Vega VEGACAL 69, Руководство по эксплуатации

Страница: 16 / 60

16
5 Connecting to power supply
VEGACAL 69 • Two-wire 4 … 20 mA/HART
31178-EN-200929
Note:
Prior to setup you have to replace these protective caps with ap-
proved cable glands or close the openings with suitable blind plugs.
On plastic housings, the NPT cable gland or the Conduit steel tube
must be screwed into the threaded insert without grease.
Max. torque for all housings, see chapter "
Technical data ".
If shielded cable is required, we recommend connecting the cable
screening on both ends to ground potential. In the sensor, the cable
screening must be connected directly to the internal ground terminal.
The ground terminal on the outside of the housing must be connected
to the ground potential (low impedance).
In Ex systems, the grounding is carried out according to the installa-
tion regulations.
In electroplating plants as well as plants for cathodic corrosion protec-
tion it must be taken into account that significant potential differences
exist. This can lead to unacceptably high currents in the cable screen
if it is grounded at both ends.
Note:
The metallic parts of the instrument (process fitting, sensor, concen -
tric tube, etc.) are connected with the internal and external ground
terminal on the housing. This connection exists either directly via
the conductive metallic parts or, in case of instruments with external
electronics, via the screen of the special connection cable.
You can find specifications on the potential connections inside the
instrument in chapter " Technical data ".
5.2 Connection procedure
Proceed as follows:
1. Unscrew the housing lid
2. If a display and adjustment module is installed, remove it by turn-
ing it to the left
3. Loosen compression nut of the cable gland and remove blind
plug
4. Remove approx. 10 cm (4 in) of the cable mantle, strip approx.
1 cm (0.4 in) of insulation from the ends of the individual wires
5. Insert the cable into the sensor through the cable entry
6. Lift the opening levers of the terminals with a screwdriver (see
following illustration)
7. Insert the wire ends into the open terminals according to the wir-
ing plan
Cable screening and
grounding