ANALOX 1371 MK 2 SURVEYOR CARBON DIOXIDE MONITOR
1371-810-03 User Manual, August 2007
917
Figure 1. Fixing Centres.
3.2
CONNECTIONS
3.2.1 Connections to remote equipment, eg Flashing beacons or High powered Sounders and data
recording devices are made through two cable glands, to the screw terminals in the middle area of
the terminal compartment. The upper row of terminals provide connections to the alarm relay
contacts and the lower row are signal input and output connections. On the 1371 Instrument,
only the extreme right hand two terminals are used on the Signal terminals - these provide a 4-
20mA DC output signal, representing 0 to 100% of Instrument measuring range. Optionally, a 0 -
1volt output can be provided instead of the 4-20mA, if this is requested when ordering.
3.2.2 On AC Supply versions, an AC mains supply of correct value as stated on the Internal label
covering the terminals, should be connected through the left most cable gland, to the terminals
marked 'L' and 'N'. The Earth lead should be fixed to the Ring connector provided on the Earthing
stud, on the Left inside wall of the Terminal compartment.
3.2.3 On DC Supply versions, a 12V DC supply should be connected to the terminals marked '12V', '+'
and '-'.
3.2.4 Remote gas sampling may be carried out by connecting up to about 30 metres of 4mm I.D. 6mm
OD plastic tubing between the 'GAS IN' bulkhead connector and the area to be monitored.
3.2.5 A Pump failure or gas flow failure Alarm circuit is incorporated and this operates a relay, whose
contacts are connected to a 3way screw terminal block, just to the left of the terminals described in
Section 3.2.1 Under normal flow conditions, the NC and CM contacts are closed and the NO and
CM contacts open. Under flow fail or power fail conditions, these contacts will change over.
3.3
COMMISSIONING
3.3.1 When the 1371 Surveyor is first switched on, it requires a period of about 40 Seconds, for the IR
Transducer to settle. During this period, the Reading on the Display will be clamped to read the
Full Scale Value of the particular Instrument.
3.3.2 When the settling time has expired, the Instrument will display the CO
2
concentration in the gas
being drawn through the Transducer, by the sample pump.
3.3.4 The Alarm setpoints should be checked and adjusted if necessary, following the procedure
outlined in Section 4 and a full Calibration carried out as detailed in Section 5.
