Campbell OBS-3A Spécifications télécharger pdf (Page 42)

Section 6. Calibration

Preparation

1. Clean containers and glassware with detergent and rinse with filtered

water.

2. Perform the calibration under fluorescent lighting.

3. Based on the material, select the appropriate sample duration from TABLE

6.2-1.

4. Open the calibration box with

and enter sediment concentration

values.

5. After each addition of sediment compute mg/l or ppm with the equations

given below.

6. Start the OBS-3A Utility and wake the OBS-3A. Click the mg/l or ppm

button.

TABLE 6.2-1. Sample Durations for

Sediment Calibrations

Sediment Seconds

Clay 10

Silt 20

Fine Sand 40

Sediment concentrations are calculated with the following equations:

mg/l





;

ppm



Where:

= Mass (mg) of sediment in suspension

= Initial water mass, )(1 i kgVu

= Initial volume (L)

= Sediment density (usually ) l/mg1065.2

7. For the zero calibration point you will need a clean black 20” x 14” x 16”

container filled with clean tap water. A Rubbermaid plastic storage box is

suitable.

8. Add 2 l of filtered water to the 1 gallon container submerging the sensor at

least 5 cm; tap bubbles off container walls.

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Campbell OBS-3A Spécifications Page 42