Endress+Hauser Nivector FTI26, Руководство по эксплуатации

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Electrical connection Nivector FTI26
14 Hauser
5.3 Post-installation check
 Is the device undamaged (visual inspection)?
 Is the device adequately protected from wet conditions and direct sunlight?
 Is the device properly secured?
 Use in hazardous areas: Is the protection cover installed?
6 Electrical connection
6.1 Connection conditions
The measuring device has two modes of operation:
• Maximum point level detection (MAX): e.g. for overfill prevention
The device keeps the electrical switch closed as long as the sensor is not yet covered by
medium.
• Minimum point level detection (MIN): e.g. Dry running protection
The device keeps the electrical switch closed as long as the sensor is covered by medium.
Choosing the MAX or MIN mode of operation ensures that the device switches in a safety-
oriented manner even in an alarm condition, e.g. if the power supply line is disconnected.
The electronic switch opens if the point level is reached, if a fault occurs or if the power
fails (quiescent current principle).
6.2 Connecting the measuring device
• Supply voltage 12 to 30 V DC
• In accordance with IEC/EN61010 a suitable circuit breaker must be provided for the
measuring device.
• Voltage source: Non-hazardous contact voltage or Class 2 circuit (North America).
• The device must be operated with a 500 mA fine-wire fuse (slow-blow) which is suitable
for DC current in accordance with IEC 60127-2.
• Depending on the analysis of the switch outputs, the measuring device works in the
MAX or MIN modes.
6.2.1 Function monitoring
With two-channel evaluation, functional monitoring of the sensor is also possible in
addition to level monitoring.
When both outputs are connected, the MIN and MAX outputs assume opposite states
(XOR) when the device is operating fault-free. In the event of an alarm condition or a cable
break, both outputs are de-energized.
Connection for function monitoring using XOR operation
Yellow LED
(ye)
Red LED
(rd)
0.5A
L– L+
2 1
3
4
K1 K2
Sensor covered
1
2 1
4
Sensor free
4 1
1 2