OM0133
31
9.2
Door and Perimeter Temperature Calibration
The DH Autoflow's inner glass door and perimeter temperature calibration is best accomplished by running the
incubator 24 hours with the water pan in place and perform the following calibration sequence, if required.
Open the incubator door and look for general condensation. Some condensation on the glass door can be
desirable as an indication of adequate humidity in the chamber. Typically, one to two inches of condensation in
the corners of the glass door indicates a properly calibrated door heater. The perimeter heater controls the
heater located on the inner chamber next to the glass door. Typically, no condensation should form on the inner
chamber next to the glass door. However, if calibration is required, simply perform the procedure as stated
below. The door and perimeter heater operates as a duty cycle percentage ON/OFF (0 is off, 100 is Full ON).
Typically, 35 to 50 percent is the most effective duty cycle for both door and perimeter heaters in 22ºC ambient
with a 37.0ºC setpoint. Default settings are door and 40% and perimeter 45%.
The following steps should be taken for setting these duty cycle percentages:
Allow incubator to stabilize at its given temperature and humidity level in run mode.
Press "SEL" to indicate LED next to temperature display.
Press and hold UP and DOWN keys simultaneously for three seconds. Temperature display
alternates between either "dor" or "PEr" and the duty cycle percentage.
Press UP or DOWN key to desired "dor" or "PEr" duty cycle percentage (press RUN/SETUP key to
change from "dor" to "PEr" and back again).
Press "SEL" to set current value and exit calibration.
9.2.1
Automatic Door and Perimeter heater duty cycle automatic control
T
he door and perimeter duty cycles are automatically reduced when the room temperature in the lab
increases enough to allow the contribution from these heaters to over heat the chamber. For example if
the door and perimeter duty cycles are set up when the room temperature is 22ºC and the room
temperature is allowed to increase to 27º. Less heat is required to keep the chamber at set-point. If the
chamber starts to overheat, the duty cycles will be reduced at a rate of 3%/per minute starting when the
chamber temperature is 0.2ºC above set-point. The duty cycles will continue to be reduced until the
chamber temperature returns to set-point. These duty cycles are continuously monitored and will be
increased slowly again, as long as the chamber temperature does not go over the set-point. If the room
ambient reduces back to 22ºC the door and perimeter duty cycles will actually be returned to their
original settings.
NOTE: If it is known that the lab room temperature where the incubator is installed will vary
significantly. (For example, the heater or air conditioning is shut off after work hours or there is no air
conditioning and the room temperature has large temperature swings.) The door and perimeter duty
cycles should be set in the lower temperature expected in the lab. Then the door and perimeter heaters
will automatically be adjusted to avoid over temperature conditions in the chamber when the room
temperature rises. In this case the chamber should be monitored for condensation regularly. If the
chamber walls and ceiling start to get excessive condensation the door and perimeter heater duty cycle
settings will need to be reduced. Do not adjust the duty cycle settings by more than 5% at a time.
9.3
Setting Air Injections
If there is still some undesired condensation in the chamber when the door and perimeter heaters are set for the
desired result, the air injections can be adjusted. There is a control for length of the air injection labeled, Air
Inject Time, and the frequency that air is injected called, Air Inject Cycle. These controls are described in more
detail in the "Opt" menu. The default is 30-second injections every 10 minutes. Start by increasing the length
of the injection by a few seconds at a time then increase the frequency if needed.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
