Thermo Fisher Scientific Alpha DO 1000 User Manual

Page 21

5. If the calibration is successful, the controller switches to the second point,

which is the high-level of dissolved oxygen. Take the probe out of the
solution and immerse it in a solution with a higher concentration of
dissolved oxygen. When the reading is stable, “READY” annunciator
comes on. Use the

▲ or ▼ keys to adjust the displayed value to the

correct value. Press ENTER key to accept the value and the status of the
probe is displayed.

NOTE: If the displayed value is > ±2 mg/l, the controller will not

accept the high-level calibration and retains the previous
calibration values.

6. After calibration, the controller automatically displays the condition of the

probe in the upper display and the temperature in the lower display. You
can view these values without calibration --- see Section 5.1.1 for
instruction. The probe condition is re-determined after each calibration.

7. Press the ENTER key. If you entered the calibration mode using the CAL

key, the controller will return to the Measurement mode. If you entered the
calibration mode from the Advanced Set-up mode, the controller will return
to the sub-function menu.

NOTE: If there is a calibration error, the controller displays “ERR”. If

this happens, push both the

▲ or ▼ keys (escape) to restart the

calibration beginning from Step 1.

NOTE: When calibrating with manual temperature compensation, the

controller automatically changes from the preset process
temperature to the calibration temperature. After leaving the
Calibration mode, the controller switches back to process
temperature (for setting the calibration temperature and the
process temperature, see Section 7.4.3).

6.2

Dissolved Oxygen Calibration in % Saturation of Oxygen

A one-point calibration is done in air. When you carry out a two-point calibration,
you need a standard D.O. buffer solution that matches the low value, which is 0%.

1. Enter Calibration mode. While in the Measurement mode, push the CAL

key and scroll to Calibration code “11”. Push the ENTER key again. The
upper and lower display reads “CAL dO”.

2. Press the ENTER key. Use the

▲ or ▼ keys to select 1- or 2-pt calibration

points.

3. For

One-Point Calibration, only calibration at the 100% level is possible.

The probe is allowed to equilibrate with air. The “CAL” indicator flashes at
the top, right-hand corner. When the reading is stable, the “READY”