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5 Connecting to power supply
PLICSMOBILE T81/B81/S81 • External GSM/GPRS/UMTS radio unit
55234-EN-170206
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
•
Connect only in the complete absence of line voltage
•
If overvoltage surges are expected, overvoltage arresters should
be installed
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
requirements of EN IEC61010-1 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.
The sensor connection cable included in the delivery is used to con-
nect the sensor.
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).
Note:
When connecting more than one HART sensor, a different address
must be assigned to each sensor (address range 1-15). Address 0
(mode 4 … 20 mA) may not be used. When assigning an address,
only one sensor should be connected to PLICSMOBILE T81. If con-
nection is already completed, the wiring must be briefly undone for
addressing. Depending on the installation location of the sensors, it
can be advantageous to carry out this addressing before installing
and connecting the sensors. This can be conveniently carried out
e.g. in the workshop. You only need a 24 Volt power supply as well as
an indicating and adjustment module PLICSCOM or the adjustment
software PACTware with VEGACONNECT.
5.2 Connection options
Power can be supplied to the sensor and PLICSMOBILE in two ways:
With this version, only one voltage supply is required for both devices.
The voltage supply is connected to the PLICSMOBILE T81. In
addition to the measured value, the sensor connection cable also
carries the voltage supply of the sensor via HART. Hence there is
no 4 … 20 mA HART signal from the sensor electronics available for
processing, e.g. via a PLC. That's why the measured value transmis-
Note safety instructions
Select power supply
Select connection cable
Cable screening and
grounding
Common voltage sup-
ply for sensor and
PLICSMOBILE