Connecting; Preparing The Connection - Siemens SITRANS L Series Operating Instructions Manual

Connecting

5.1

Preparing the connection

Safety instructions
Always keep in mind the following safety instructions:
•
•
Only connect or disconnect in de-energized state.
Voltage supply
The data for power supply are specified in chapter "Technical data".
Power the transmitter via an energy-limited circuit (power max. 100 W) acc. to
IEC 61010-1, e.g.
•
•
Keep in mind the following additional factors that influence the operating voltage:
•
•
Connection cable
The transmitter is connected with standard two-wire cable. If electromagnetic inter-
ference is expected which is above the test values of EN 61326-1 for industrial areas,
screened cable should be used.
Screened cable generally necessary in HART multidrop mode.
SITRANS LR120
Operating Instructions, 01/2020, A5E49829026
Carry out electrical connection by trained, qualified personnel authorised by the
plant operator
If overvoltage surges are expected, overvoltage arresters should be installed
WARNING
WARNING
Class 2 power supply unit (acc. to UL1310)
SELV power supply unit (safety extra-low voltage) with suitable internal or exter-
nal limitation of the output current
Lower output voltage of the power supply unit under nominal load (e.g. with a
transmitter current of 20.5 mA or 22 mA in case of fault)
Influence of additional transmitters in the circuit (see load values in chapter
"Technical data")
5
19