Connecting To Power Supply; Preparing The Connection - Vega VEGABAR 81 Operating Instructions Manual

5 Connecting to power supply

Safety instructions
Voltage supply
Connection cable
Cable screening and
grounding
Cable glands
24
5 Connecting to power supply
5.1

Preparing the connection

Always keep in mind the following safety instructions:
•
Carry out electrical connection by trained, qualified personnel
authorised by the plant operator
•
If overvoltage surges are expected, overvoltage arresters should
be installed
Warning:
Only connect or disconnect in de-energized state.
The voltage supply and the signal transmission are carried out via the
four-wire, shielded connection cable from the Primary Device.
You can find the data for this signal circuit in chapter " Technical data".
The device is connected via the supplied four-wire, shielded cable or
a similar cable provided by the customer. You can find detailed infor-
mation of the connection cable in chapter " Technical data".
Use a cable gland suitable for the cable diameter to ensure the seal
effect of the cable gland (IP protection).
The shielding of the cable between Primary and Secondary Device
must be connected on both ends to ground potential. In the sensor,
the shielding is 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).
Metric threads:
In the case of instrument housings with metric thread, the cable
glands are screwed in at the factory. They are sealed with plastic
plugs as transport protection.
Note:
You have to remove these plugs before electrical connection.
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.
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".
VEGABAR 81 • Secondary Device for electronic differential pressure