13
5 Connecting to power supply
PLICSMOBILE • Mobile network unit PLICSMOBILE T81
55234-EN-191217
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
•
The electrical connection must only be carried out by trained,
qualified personnel authorised by the plant operator.
•
If overvoltage surges are expected, overvoltage arresters should
be installed.
Warning:
Connect only in the complete absence of line voltage.
Power can be supplied optionally via PLICSMOBILE B81 or a sepa-
rate power supply unit.
When using a power supply unit, the secondary circuit must be
separated from the primary circuit by double or reinforced insulation
(according to the nationally valid safety standards).
The air and creeping distances in PLICSMOBILE T81 meet the re-
quirements of EN IEC 61010-1 for secondary circuits with reinforced
insulation under overvoltage category III (altitude up to 2000 m).
The voltage supply of PLICSMOBILE T81 is connected with standard
cable according to the national installation standards.
If electromagnetic interference is expected which is above the test
values of EN 61326-1 for industrial areas, screened cable should be
used.
Make sure that the cable used has the required temperature resist-
ance and fire safety for max. occurring ambient temperature
We generally recommend the use of shielded cable for HART
multidrop mode.
Use cable with round cross section for instruments with housing and
cable gland. Use a cable gland suitable for the cable diameter to
ensure the seal effect of the cable gland (IP protection rating).
Connect the cable screen on the sensor side to ground potential.
In the sensor, the screen must be connected directly to the internal
ground terminal. The ground terminal on the outside of the sensor
housing must be connected to the potential equalisation (low imped-
ance).
5.2 Connection options
Power can be supplied to the sensors and PLICSMOBILE in two
ways:
This version requires only one power supply for all devices. Up to
15 HART sensors can be connected to the PLICSMOBILE T81. The
power supply is connected to the PLICSMOBILE T81. In addition to
the measured value, the sensor connection cable also transmits the
power supply to all sensors via HART.
Safety instructions
Voltage supply
Connection cable
Cable screening and
grounding
Common voltage sup-
ply of the sensors and
PLICSMOBILE
