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5 Connecting to power supply
PLICSMOBILE T81/B81/S81 • External GSM/GPRS/UMTS radio unit
55234-EN-170206
sion can only be carried out via radio transmission through e-mail/
SMS/VEGA Inventory System.
With this version, the sensor and the PLICSMOBILE T81 are each
powered via a separate power supply. Here, the measured values can
be transmitted via radio communication and the 4 … 20 mA HART
signal is available in parallel for processing, e.g. via a PLC.
HART communication
If the internal resistance of the connected power supply for the sensor
is less than 230 Ω, the HART signal is extremely damped or short-
circuited. Digital communication with PLICSCOM is then no longer
possible. With low impedance processing systems, a resistance of
approx. 230 Ω must be looped into the 4 … 20 mA cable. This resist-
ance is already integrated in PLICSMOBILE T81 and can be looped
automatically into the circuit by selecting the appropriate wires (see
wiring plan).
The connection to power supply is carried out as described in the
respective operating instructions manual.
5.3 Connection steps sensor connection cable
The sensor connection cable is used for transmission of the meas-
ured value from the sensor to the PLICSMOBILE T81. In addition, it
can also transmit the voltage supply for the connected sensor.
The sensor connection cable is available in Ex version (blue)
as well as in non-Ex version (black). It can be ordered in three
lengths (5/10/25 m) and can be shortened afterwards to individual
lengths. On one end there is a ready-for-use plug for connection to
PLICSMOBILE T81. On the other end are free cable ends for direct
connection to the sensor.
To connect, proceed as follows:
1. Connect the colour coded wire ends to the respective sensor
terminals, as described in the wiring plan and the operating
instructions of the sensor.
2. Isolate unused wires, depending on connection type and cable
version
3. Connect the screen to the internal ground terminal, connect the
outer ground terminal on the housing to potential equalisation
4. Tighten the compression nut of the cable entry gland. The seal
ring must completely encircle the cable
5. Insert the plug of the sensor connection cable into the plug con-
nection on PLICSMOBILE T81
6. Tighten plug connection
5.4 Connection steps voltage supply
The connection of the voltage supply is made via spring-loaded termi-
nals in the electronics compartment. A small screwdriver is required
to open the terminals. Solid as well as flexible cores without cable end
sleeves can be used.
Separate voltage sup-
ply for sensor and
PLICSMOBILE
Connection technology
