Hach-Lange 5740 sc - Manual (Page 20)

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Operation
4.7.3 Sample Cal—Calibration by Comparison to a Hand-held DO Analyzer
1. Place the dissolved oxygen sensor as close to the DO sensor as possible.
2. Wait for the hand-held DO analyzer to stabilize.
3. Select the Main Menu.
4. From the Main Menu, select SENSOR SETUP and confirm.
5. Select the appropriate sensor if more than one is attached and confirm.
6. Select CALIBRATE and confirm
7. Select SAMPLE CAL.
8. Select the available Output Mode (Active, Hold, or Transfer) from the list box and
confirm.
9. The display will show “PRESS ENTER WHEN STABILIZED” and the current DO and
temperature readings. After confirmation or when the reading has been accepted as
stable, the display will change to an entry screen. Without confirmation, the sensor
will determine when the reading is stable. Two to three minutes for the reading to
stabilize is typical, however, if it has not stabilized after 45 minutes, the display will
show “UNABLE TO CALIBRATE”.
10. When a stable reading has been accepted, the display will show “SAMPLE CAL” and
an area for entry of the value obtained from the Winkler Titration.
11. Change the displayed reading to match the hand-held DO analyzer memory.
12. After calibration, one of the responses in Table 2 on page 17 will be displayed.
4.7.4 Concurrent Calibration of Two Sensors
1. Begin a calibration on the first sensor and proceed when “WAIT TO STABILIZE” is
displayed.
2. Select the BACK button, then LEAVE. The display will return to the Main
Measurement screen.
3. Begin the calibration for the second sensor and continue until “WAIT TO STABILIZE”
is displayed.
4. Select the BACK button, then LEAVE. The display will return to the Main
Measurement screen and the reading for both sensors will be flashing.
5. To return to the calibration of either sensor, select the Main Menu button. Select
SENSOR SETUP and confirm. Select the appropriate sensor and confirm .
6. The calibration in progress will be displayed. Continue with the calibration.