Vega POINTRAC 31 Operating Instructions Manual page 21

Cable screening and
grounding
Connection technology
Connection procedure
POINTRAC 31 • Foundation Fieldbus
NPT thread
In the case of instrument housings with self-sealing NPT threads, it is
not possible to have the cable entries screwed in at the factory. The
free openings for the cable glands are therefore covered with red dust
protection caps as transport protection.
Before setup you have to replace these protective caps with approved
cable glands or close the openings with suitable blind plugs. Unused
cable glands do not provide sufficient protection against moisture and
must be replaced with blind plugs.
The suitable cable glands and blind plugs come with the instrument.
Make sure that the cable screen and grounding are carried out ac-
cording to Fieldbus specification. We recommend to connect the
cable screening to ground potential on both ends.
In systems with potential equalisation, connect the cable screening
directly to ground potential at the power supply unit, in the connection
box and at the sensor. The screen in the sensor must be connected
directly to the internal ground terminal. The ground terminal outside
on the housing must be connected to the potential equalisation (low
impedance).
The voltage supply and signal output are connected via the spring-
loaded terminals in the housing.
Connection to the display and adjustment module or to the interface
adapter is carried out via contact pins in the housing.
Proceed as follows:
The procedure applies to instruments without explosion protection.
1. Unscrew the big housing cover
2. Loosen compression nut of the cable gland and remove blind
plug
3. 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
4. Insert the cable into the sensor through the cable entry
5 Connecting to power supply
21