O2NE+ & Safe-Ox+
User Manual
Int. Approved
Document ref: P0120-820-14
August 2017
Page 10 of 23
Commercial in Confidence
4.7
Alarm relay output models
You may have ordered your Ax
O2NE+™/Safe-Ox+™ with a relay. The relay contacts are ‘Volt-
Free’ single pole changeover, rated 240VAC/30VDC 2 amps. The relay is non-latching. This
means the relay will only initiate when gas is present. As standard the relays are setup in a
fail-safe configuration. This means that the relay is energised during normal operation. Please
note that on power up the relay is only energised after the 10 second start-up period. See
below for details of how the relay should be connected.
4.8
Relay wiring
The cable gland is for cables of outside diameter between 5 and 7mm, if cable fitted is outside
that range, a suitably specified cable gland must be used. Ensure that the gland is properly
tightened. Test that the cable is adequately gripped by the cable gland. Ensure that the cable
is suitable for purpose, the load is within the limits of the relay, 240VAC/30VDC, 2 amps, and
the insulation of the external circuit meets the requirements for basic insulation
240VAC/30VDC, 2 amps. After completing wiring, ensure that the terminal box cover is securely
replaced.
RELAY TERMINAL BOX TERMINATIONS
4.9
4 to 20mA output models
You may have ordered your Ax
O2NE+™/Safe-Ox+™ with a 4 to 20mA output. A 2m cable is
factory fitted to the instrument. The 4 to 20mA output current is generated by the instrument.
