Eppendorf Galaxy CO2 Sensor - Manual (Page 48)

Operating controls and function for Galaxy 170 S Incubator
Galaxy
® 170 R/170 S CO
2
Incubators
English (EN)
48
2. Press the Enter key to begin the cycle.
The Auto Zero System automatically re-references the CO
2
Sensor to atmospheric CO
2
in the following
way:
•
A small pump switches on for 2 minutes pumping filtered atmosphere at 0.3 liters/minute into the
measuring chamber of the sensor. This displaces the chamber atmosphere completely from the
sensor.
• At the end of the countdown, the Control System adjusts the auto-zero factor to reference the sensor
to 0.05 % CO
2
which is the approximate atmospheric level.
• The pump switches off and chamber atmosphere moves back into the measuring chamber of the
sensor. This takes 3 minutes after which the normal CO
2
control takes over.
• On completion of the auto-zero a prompt will appear:
CO2 AUT.O ZER.O IN RAN.GE
3. Press the ( * ) key to finish the cycle and return to the main display.
If the CO
2
Auto-Zero cannot reference the signal to atmosphere at the end of the Auto-Zero, the
following message will appear:
CO2 AUT.O ZER.O FAI.LED
This means that the CO
2
sensor is defective and requires replacement. If this occurs, please contact
your local distributor immediately.
The default setting for the auto-zero system is 28 days of running time for the incubator. After the incubator
has been switched on for a total of 28 days (672 hours), the auto-zero will automatically take place.
7.5.2 Changing auto-zero frequency
To change the frequency of the auto-zero
1. Press the Enter and ▲ keys simultaneously.
The following message will be displayed: PRG.A2 .
2. Press Enter.
The display changes to 28 DAY .
By pressing the ( * ) and enter keys this value can be changed in steps from 28 to 14, 7, 1 or OFF .
3. Press Enter to confirm the new setting.
If a CO
2
alarm occurs, the auto-zero will automatically take place after 1 minute. This is to confirm that the
CO
2
sensor is correctly referenced.
If after a 15-minute delay, the CO
2
is still in an alarm condition and re-alarms, it will again auto-zero.
In the event of high CO
2
alarms, open the inner door for a few seconds to ensure that the CO
2
level drops
below setpoint. Also check that the CO
2
pressure is set correctly to 5 PSI (0.35 bar).
In the event of low CO
2
alarms, check that the CO
2
supply is present and set to the correct pressure.