NivoRadar
®
Continuous level measurement
Series NR 7200
Technical information / Instruction manual
page 21
Connecting to power supply
Preparing the connection
Always keep in mind the following safety instructions:
•
Carry out electrical connection by trained, qualified personnel
authorised by the plant operator
Warning:
Only connect or disconnect in de-energized state.
The data for power supply are specified in chapter " Technical
data".
Note:
Power the instrument via an energy-limited circuit (power max.
100 W) acc. to IEC 61010-1, e.g.
•
Class 2 power supply unit (acc. to UL1310)
•
SELV power supply unit (safety extra-low voltage) with suitable
internal or external limitation of the output current
Keep in mind the following additional factors that influence the
operating voltage:
•
Lower output voltage of the power supply unit under nominal
load (e.g. with a sensor current of 20.5 mA or 22 mA in case of
fault signal)
•
Influence of additional instruments in the circuit (see load values
in chapter " Technical data")
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.
The instrument is connected with standard two-wire cable. If elec-
tromagnetic interference is expected which is above the test values
of EN 61326-1 for industrial areas, shielded cable should be used.
Note:
Shielded cable generally necessary in HART multidrop mode.
Note:
If the temperatures are too high, the cable insulation can be dam-
aged. Hence keep apart from the ambient temperature also the
self-heating of the instrument for the temperature resistance of the
cable in the connection compartment in mind
1)
Metric threads
In the case of instrument housings with metric thread, the cable
gland is screwed in at the factory. It is sealed with plastic plugs as
transport protection.
Safety instructions
Voltage supply
Connection cable
Cable gland
1) With an ambient temperature ≥ 50 °C (122 °F) the connection cable should
be suitable for a temperature which is at least 20 °C (36 °F) higher.
