NAR300 system for high temperature
Electrical connection
Hauser
39
6.5
Operating principles of alarm activation
The oil leak detection signal detected by the NAR300 float sensor is converted to a power
signal in the transmitter or the sensor I/F Ex box. After this, it is connected to the current
detection circuit via the Ex [ia] safety barrier in the transmitter. In the current detection
circuit, the presence or absence of an oil leak alarm signal is determined by the magnitude
of electrical current values, and the alarm output relay is turned on or off by the operation
delay circuit.
The delay time can be set, and there is a trimmer for setting the delay time in the alarm
delay circuit. A fail-safe function is available in the relay contact output (refer to the
following table).
Between
terminals
NRR262 between NC and COM
NRR262 between NO and COM
Condition
NRR261 between NC and COM terminal
No. 11, 13
NRR261 between NO and COM terminal
No. 13, 15
Non-alarm
Contact point is open
Contact point is closed
Oil leak alarm
Contact point is closed
Contact point is open
Power OFF
Frozen liquid
The high-temperature sensor is exclusively for use in the presence of water; an alarm
will be activated in an empty pit.
NAR300 current value
Non-alarm
12 mA
Oil leak alarm
16 mA
Other trouble
< 10 mA or 14 mA <
