Eppendorf Galaxy CO2 Sensor - Manual (Page 81)

Equipment options
Galaxy ® 170 R/170 S CO
2
Incubators
English (EN)
81
1. Remove the black plastic protective cover (making sure that the hydrophobic filter cap is not removed
with it) from the port inside the chamber. Retain the cover for use when you clean the chamber.
2. Open the nitrogen gas supply from the tank and set the N
2
tank’s outlet pressure gauge to 1.5 bar.
3. Set the nitrogen regulator to 14.5 PSI (1 bar). The nitrogen will be fed into the incubator through a filter
that is already installed in the gas line. The gas flow rate is approximately 20 liters/minute.
Be sure to humidify the incubator and leave it overnight to stabilize before proceeding further.
To automatically calibrate the sensor to atmospheric oxygen levels, select OXYGEN SENSOR – REF TO
ATMOSPHERE in the USER menu, and then follow the onscreen instructions.
The oxygen reading is automatically adjusted to 19.7 %, which is the true reading taking into account the
Relative Humidity in the chamber.
12.5.3 Enabling or disabling O
2
control
To enable oxygen control:
1. Select the USER screen by pressing the USER function key.
2. Use the direction keys to select MANUAL DISABLE.
3. Press the ENTER function key, then use the direction keys to select ON for Oxygen Control.
4. Press the ENTER function key again.
Program the required oxygen level in the PROG screen, following the onscreen instructions.
To disable oxygen control, follow the pattern used to enable it, but this time select USER, MANUAL
DISABLE, ENTER, OFF and then ENTER again.
12.5.4 Alarms
The alarm levels are set automatically to ± 0.5 % above and below the programmed value, but these points
can be altered in the
ALARM screen. In addition, the re-arming of the alarm can be delayed until the
Programmed Value is achieved by selecting the relevant option in the ALARM screen.
For example, it is possible at low oxygen levels that the CO
2
and O
2
levels might not fully recover within the
Alarm Limits after the 15-minute DELAY IN ARMING AFTER DOOR OPENING period has elapsed, so this
time period can be increased in the ALARM screen to suit individual circumstances.
12.5.5 Referencing to atmosphere
To reference the oxygen sensor to atmospheric oxygen levels, (see Referencing to atmosphere on p. 74).
• If the programmed O
2
level is close to the ambient oxygen, it may be necessary to reduce
the cylinder pressure below 1 bar to stop the oxygen level from undershooting the
programmed value.
• When working at 0.1% O
2
, set the CO
2
pressure to 10 PSI (0.7 bar).