Rae FMC-40, Operating Handbook

Page: 8 / 16

8
Commissioning
Before applying power to the instrument ensure that all detector heads are connected to
the sensor terminals on the printed circuit board (fig 2) and that each detector head is
connected to its appropriate channel, identified by a small circular, coloured label:
WARNING – DO NOT INSERT OR REMOVE ALARM CARDS FROM THE
MOTHERBOARD WHILE THE POWER IS ON
Red = flammable
Yellow = toxic
Blue = oxygen
Green = others
Switch on power to the instrument.
Check that the green ʻPʼ power lamp is on.
Each channel alarm card has a green (ACTIVE) indicator located on the mother board
(D102, D202, D302, D402). On power up these will flash for 60 seconds indicating that the
sensors are stabilising, during this period all alarms are held in the off condition.
Where an internal standby battery has been supplied the connectors should be made on
JP11 and JP12.
Re-set alarms by pressing the reset button located on the front panel.
Allow ten minutes for the sensors to stabilise.
Select channel 1 and for flammable or toxic sensors adjust meter to read zero by means
of appropriate ZERO POTENTIOMETER marked (Z) on the alarm module, or for oxygen
sensor adjust the s-span potentiometer for a reading of 20.8 repeat for Channel 2, 3 and 4.
CALIBRATION
Establish calibration figures with respect to the L.E.L. limit or the T.L.V. limit of the
calibration gas being used. See page 13.
The following calibration gases are recommended:
Flammable gases - 2.5% methane in air. Toxic gases - T.L.V. When using this gas ensure
adequate ventilation.
If necessary zero each detector channel in clean air (for ambient oxygen monitoring the
meter should be adjusted to read 20.8% using the s-span potentiometer).
Apply the calibration gas to the appropriate head at a flow rate of approximately 1 litre per
minute.
When the meter reads a steady value adjust the Span Potentiometer marked (S) to obtain
the correct reading for the calibration gas being used.
SERVICE ADJUSTMENTS
The following adjustments need only be made if the standard factory settings (see test
certificate) are to be adjusted.