Connecting To Power Supply; Preparing The Connection - Siemens SITRANS LG260 Operating Instructions Manual

Safety instructions
Voltage supply
Connection cable
Cable glands
Cable screening and
grounding
PBD-51041061
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 instrument requires a operating voltage of 9 ... 32 V DC. Operat-
ing voltage and the digital bus signal are carried on the same two-wire
connection cable. Power is supplied via the H1 power supply.
Connection is carried out with screened cable according to Fieldbus
specification.
Use cable with round cross section for instruments with housing and
cable gland. To ensure the seal effect of the cable gland (IP protection
rating), find out which cable outer diameter the cable gland is suitable
for.
Use a cable gland fitting the cable diameter.
Make sure that the entire installation is carried out according to the
Fieldbus specification. In particular, make sure that the bus is termi-
nated with suitable terminating resistors.
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".
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.
SITRANS LG260 - Operating Instructions
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