Eppendorf Galaxy CO2 Sensor - Manual (Page 84)

Equipment options
Galaxy
® 170 R/170 S CO
2
Incubators
English (EN)
84
4. Securely attach the two-stage pressure regulator to the nitrogen tank’s outlet and to the inline pressure
regulator’s inlet with tubing, securing both ends with clips.
5. Connect the inline pressure regulator’s outlet to the incubator’s N
2
inlet on the right side of the control
box at the rear of the incubator (see Fig. 2-3 on p. 11); secure both ends with clips.
6. Proceed as indicated in (see Setting up O
2
control on p. 84).
12.6.2 Setting up O
2
control
Oxygen control is tailored such that both the O
2
and the CO
2
levels are achieved at approximately the same
time, via control of the O
2
or N
2
valve’s duty cycle.
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.
4. Install the oxygen cylinder in the same manner as outlined for the nitrogen cylinder installation (see
Setting up the N
2
tank on p. 83), using the incubator’s O
2
inlet, of course. For this application, you will
need another two-stage pressure regulator and another inline pressure regulator.
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.
12.6.3 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 add an automatic gas cylinder changeover instrument: with the incubator turned off,
connect its inlet to the two-stage pressure regulator’s outlet, and the changeover instrument’s
outlet to the inline pressure regulator’s inlet with tubing, securing the ends with tubing clips.
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.
Be sure to humidify the incubator and leave it overnight to stabilize before proceeding further.