Calibration; Calibration In Air - Hach LDO User Manual

Operation
Elevation in feet Barometric pressure in mm Hg
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500

5.6 Calibration

5.6.1 Calibration in Air

24
Table 4 Elevation Barometric Pressure
733
720
708
695
683
671
659
647
635
624
The dissolved oxygen sensor has been calibrated at the factory to the specifications listed
on Specifications on page
dissolved oxygen technology, sensor calibration is seldom or never necessary. The
calibration procedures will result in an instrument offset or gain correction and may be
performed if required by regulatory agencies. The air calibration is the most accurate
method. The calibration by comparison method is the least accurate and is therefore not
recommended.
For continued accuracy and repeatability, the manufacturer recommends replacing the
sensor cap after one year of operation.
1. Remove the sensor from the process stream and wipe with a wet cloth to remove
debris and biological growth.
2. Place the sensor in the supplied Calibration Bag, add a small amount of water
(25–50 mL) and secure the bag to the sensor body.
3. Lay the bagged probe on a flat surface where it will not be exposed to a heat source.
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 AIR CAL. Select the available Output Mode (Active, Hold, or Transfer) from the
list box and confirm.
8. "Move the sensor to air" will be displayed if the sensor is moved to air (in the
calibration bag).
9. The Air Calibration procedure will begin and "Wait to Stabilize" will be displayed. The
current DO and temperature readings will be displayed. Confirm.
10. The calibration will automatically occur when the reading stabilizes or when the
reading is confirmed to base the calibration on the currently displayed value. Two to
Elevation in feet
7000
7500
8000
8500
9000
9500
10000
10500
11000
—
5. Due to the inherent accuracy and stability of the luminescent
Barometric pressure in mm Hg
590
579
568
559
548
538
527
517
506
—