Power Supply Connection; Connecting External Sensors - Endress+Hauser RTA421 Mode D'emploi

3.2 Power supply connection

- Before installing the unit please check that the power supply
corresponds with that shown on the unit legend plate..
- A power isolator must be situated within easy reach of the
unit, this should also be fused with ≤ 10 A.
L/ L+
N/ L
The terminals are internally linked and can be used for serial
connection.

3.3 Connecting external sensors

If there is a possibility of electrical transients on long signal
cable runs we would recommend that an overvoltage protection
unit is used.
3.3.1. Active current or voltage sources (e.g. transmitters with
their own power supply and active output).
Current input
0/4...20 mA
-
+
-
L/ L+ -
N/ L
Voltage input
0/2...10 V
Contactor
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