Electrical Connection; Connecting The Device - Endress+Hauser Liquiphant FTL33 Operating Instructions Manual

Electrical connection

6 Electrical connection
The device has two operating modes: maximum safety (MAX) and minimum safety (MIN). By
choosing the corresponding operating mode, the user ensures that the device also switches in
a safety-oriented manner even in an alarm condition, e.g. if the power supply line is
disconnected.
• Maximum safety (MAX)
The device keeps the electronic switch closed as long as the liquid level is below the fork.
Sample application: overfill protection
• Minimum safety (MIN)
The device keeps the electronic switch closed as long as the fork is immersed in liquid.
Sample application: Dry running protection for pumps
The electronic switch opens if the limit is reached, if a fault occurs or the power fails
(quiescent current principle).
6.1

Connecting the device

In accordance with IEC/EN61010 a suitable circuit breaker must be provided for the
device.
6.1.1 Electronic version 3-wire DC-PNP
3-wire DC-PNP is preferably used in conjunction with programmable logic controllers (PLC),
DI modules as per EN 61131-2. Positive signal at the switch output of the electronics (PNP).
Voltage source: non-hazardous contact voltage or Class 2 circuit (North America).
Connection with M12 plug
Depending on the analysis of the switch outputs, the device works in the MAX (maximum
safety) or MIN (minimum safety) mode.
A cable is optionally available
 10 M12 plug
20
Liquiphant FTL33
A0022901
Endress+Hauser