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5 Connecting to power supply
VEGAPULS C 21 • SDI-12
58342-EN-200121
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
•
Carry out electrical connection by trained, qualified personnel
authorised by the plant operator
•
If overvoltage surges are expected, overvoltage arresters should
be installed
Warning:
Only connect or disconnect in de-energized state.
The device is supplied with power via an SDI-12 datalogger.
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
The data for power supply are specified in chapter "
Technical data
".
The instrument is connected with standard three-wire cable without
screen. If electromagnetic interference is expected which is above the
test values of EN 61326-1 for industrial areas, screened cable should
be used.
5.2 Wiring plan
1
2
3
4
Fig. 15: Wire assignment in permanently connected connection cable
Wire colour
Function
Polarity
1
Brown
Voltage supply
+
2
Blue
Voltage supply
-
3
White
SDI data
+
4
Shielding
5.3 Switch-on phase
After connection to the power supply, the device carries out a self-
test.
Safety instructions
Voltage supply
Connection cable
Wire assignment, con-
nection cable
