Barnstead International MaxQ 4000, Manual

Page: 19 / 36

3. Press and hold the “star” (
✳
) key and using the
up or down arrow key, adjust the set point to
the desired temperature.
4. Allow the shaker to run until chamber tempera-
ture has stabilized.
5. The controller display should now be indicating
the set point temperature. Make note of the
thermometer reading.
6. Press and hold both arrow keys until the con-
troller display indicates “tunE”. Release the
arrow keys. Press and release the down arrow
key, the display should now alternate between
“LEUL” and “1”. Press and hold the “star” (
✳
)
key and using the up arrow key adjust the dis-
play to read “3”. Release the “star” (
✳
) key. The
display should now alternate between “LEUL”
and “3”. Press and release the up arrow key
until the display indicates “Zero”. The display
should now alternate between “Zero” and a
numerical value.
7. Using the examples shown in Figure 4 and the
thermometer value obtained in step 5 above,
enter the correct “Zero” value into the controller
by pressing the “star” (
✳
) key and using the up
or down arrow key. If there is already a “Zero”
value present then add the new value to the
one already present.
8. When the correct “Zero” value has been
entered, press and hold the two arrow keys
together until the display again indicates the
chamber temperature. If the procedure was
done correctly, the controller display should
now agree with the thermometer reading to
within ±0.5°C.
9. Allow the unit to run for at least an additional 30
minutes.
10. Re-check the thermometer reading. The con-
troller display and the thermometer should
agree to within ±0.5°C. If not repeat steps 6, 7
and 8.
19
O
PERATION
Thermometer = 60 °C
Controller Reading = 65 °C
Subtract = -5 °C
Enter Zero value of -5 °C
Thermometer = 70 °C
Controller Reading = 65 °C
Subtract = +5 °C
Enter Zero value of +5 °C
Figure 4: Determining Zero Value