MANUALP/4000_SERVICE_0712 July2012
18
6 Release all buttons. After about 3 seconds the temperature display will
show [---] then a HEXIDECIMAL number for about 2 seconds (This
number may be noted as a reference to the current calibration) then
another [---] and beep. The enclosure will now begin to adjust itself so
that the reference thermometer temperature matches the SET POINT
temperature. The indicated temperature will show a temperature offset
from the SET POINT Temperature immediately after the calibration. This
is normal as the controller is now endeavoring to match the SET POINT
to the work space reference thermometer.
The procedure may need to be repeated to obtain the best final calibration.
The temperature should be recorded on a daily basis by placing a thermometer
in the workspace so that it can be read without opening the inner glass doors
and the long term temperature performance can then be plotted to give an
assurance of correct temperature performance. Similarly, the CO
2
should be
checked and monitored regularly using the independent monitor. Record these
for long term assurance.
CO
2
CALIBRATION – THERMAL CONDUCTIVITY SENSOR
There are two modes of calibration for the THERMAL CONDUCTIVITY CO
2
system. An AUTO-CALIBRATION (AUTO-CAL) and MANUAL CALIBRATION
(MAN-CAL). Both types perform the same operation. AUTO-CAL enables the
enclosure to perform the calibration at ‘quiet’ times of operation, whereas MAN-
CAL is used when the cabinet has been empty of CO
2
for a long period. Both
require the enclosure to be stabilised at the desired set Temperature.
AUTO-CAL
The normal method of calibrating the CO
2
concentration is by using the
AUTO-CAL facility. To force the controller to carry out an AUTO-CAL the
following procedure is recommended.
1 Change the Temperature Set Point by 0.1
o
C (eg. if your normal operating
Temperature Set Point is 37.0
o
C change it to 36.9
o
C).
2 The CO
2
display should now be flashing, this indicates that the CO
2
is
now out of calibration. Note that the operation of the CO
2
gas inlet
solenoid(s) will be inhibited while the CO
2
display is flashing.
3OPEN both the outer and inner incubator doors, and leave them open for
at least 30 seconds. (This is to flush the enclosure of CO
2
gas).
4 CLOSE both doors.
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