Connecting To Voltage Supply; Preparing The Connection - Burkert 8185 Mise En Service

Connecting to voltage supply

Note safety instructions
Take note of safety
instructions for Ex
applications
Select power supply
Selecting connection cable
Cable screening and ground-
ing
14
5 Connecting to voltage supply

5.1 Preparing the connection

Generally note the following safety instructions:
Connect only in the complete absence of line voltage
l
If overvoltage surges are expected, overvoltage arresters
l
should be installed
In hazardous areas you should take note of the appropriate
regulations, conformity and type approval certificates of the
sensors and power supply units.
Power supply and current signal are carried on the same two-
wire cable. The voltage supply range can differ depending on
the instrument version.
The data for power supply are stated in chapter "Technical
data" in the "Supplement".
Provide a reliable separation between the supply circuit and
the mains circuits according to DIN VDE 0106 part 101.
Bear in mind the following factors regarding supply voltage:
Output voltage of the power supply unit can be lower under
l
nominal load (with a sensor current of 20.5 mA or 22 mA in
case of fault message)
Influence of additional instruments in the circuit (see load
l
values in chapter "Technical data")
LEVEL TRANSMITTER 8185 is connected with standard two-
wire cable without screen. The outer cable diameter of
5 ... 9 mm ensures the seal effect of the cable gland. If strong
electromagnetic interference is expected, screened cable
should be used.
Connect the cable screen on both ends 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 housing must be connected to the potential equalisation
(low impedance).
If potential equalisation currents are expected, the connection
on the processing side must be made via a ceramic capacitor
(e.g. 1 nF, 1500 V). The low frequency potential equalisation
currents are thus suppressed, but the protective effect against
high frequency interference signals remains.
LEVEL TRANSMITTER 8185 - 4 ... 20 mA/HART