Hach-Lange SOLITAX sc - Manual (Page 18)

18
Operations
4.6.3 Calibration for Suspended Solids
Suspended solids calibration requires calibration to the actual sample. This optimizes the
compensation for the particle size and shape typical at a measuring site. It is best
performed by mounting the sensor as usual for normal measurement, and then grab
samples collected and evaluated by laboratory methods. While a single point calibration is
usually sufficient to provide accuracy, the SOLITAX does offer the ability to calibrate with
up to 5 calibration points.
1. From the Main Menu, select SENSOR SETUP and press confirm.
2. Select the appropriate sensor if more than one is attached and confirm.
3. Select CALIBRATE and press confirm.
4. Select CONFIGURE and confirm.
5. Select the number of points desired for calibration (the unit with linearly interpolate
values between calibration points). Select Factor for a single point calibration.
6. Mount the sensor as is during normal operation. Alternatively, place the sensor in the
calibration cylinder (or a container with dark, non-reflective walls) 2 inches of
clearance from the probe face with the probe face submerged by 1 inch or more.
7. Select SENSOR MEASURE and record the reading.
8. Immediately take a grab sample. Determine the total suspended solids using a
gravimetric method such as Method 2540 D in Standards Methods for the
Examination of Water and WasteWater.
9. Calculate the new factor. Refer to section 4.6.3.1 for single point (Factor) calibration.
Refer section 4.6.3.2 on page 18 for multiple point calibrations.
10. Select FACTOR and press confirm. The corrected measurement should be displayed.
4.6.3.1 For Single Point (Factor) Calibration
Calculate the new factor:
For example, if a sample measures 2.3 g/L using the SS sensor and the gravimetric value
was 2.0 g/L, the new factor would be calculated as follows:
4.6.3.2 Multi-point Calibration
1. Repeat steps 6 – 8 in section 4.6.3 on page 18 at different times to obtain different
measurements.
2. From the CONFIGURE menu, select the appropriate calibration point menu.
3. Enter the pairs of values for each reading, the target value being the laboratory
determined value, and the actual value being the reading that the SOLITAX produced
in step
5 . The pairs should be entered in order from lowest values to highest.
New Factor =
Determined gravimetric value
measured value
New Factor =
2.0 g/L
= 0.87
2.3 g/L