Siemens SITRANS LR140, Руководство по эксплуатации

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Connecting
5
5.1 Preparing the connection
Safety instructions
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.
Voltage supply
The data for power supply are specified in chapter " Technical data .
Note
Power the transmitter 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
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 )
Connection cable
Use cable with round cross section for transmitters 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.
Shielded, two-wire cable is recommended for connecting the device.
Note
If the temperatures are too high, the cable insulation can be damaged. Hence keep
apart from the ambient temperature also the self-heating of the transmitter for the
SITRANS LR140
Operating Instructions, 08/2020, A5E50352144
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