horiba U-51, Инструкция по эксплуатации

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3 Basic Operation
54

Turbidity (TURB) calibration
Note

To support a wide range of sample concentrations, turbidity is divided into three measurement
ranges: 0.0 to 9.9 NTU, 10 to 100 NTU, and over 100 NTU.

When manually calibrating turbidity, you can select two calibration procedures (one zero-point
calibration procedure and a span calibration procedure for one of the three measurement
ranges), three calibration procedures (one zero-point calibration procedure and a span
calibration procedure for two of the three measurement ranges) or four calibration procedures
(one zero-point calibration procedure and span calibration procedures for all three measurement
ranges). Carry out the four calibration procedures to ensure good measurement precision
throughout all measurement ranges.

Always use the calibration cup provided. Using other containers can create effects from ambient
light that cause incorrect calibration.

Preparing the standard solutions
1.
Weigh out 5.0 g of hydrazine sulfate (commercial special grade or above), and
dissolve it in 400 mL of deionized water. Dissolve 50 g of hexamethylene tetramine
(commercial special grade or above) in 400 mL of deionized water in anther flask.
2.
Mix the two solutions and add deionized water until the total solution volume is
1000 mL, and mix well. Store this solution at a temperature of 25

C ±3

C for 48
hours.
The turbidity value (TURB) of this solution is equivalent to 4000 NTU.
3.
Dilute 4000 NTU-solution 5 times (use a pipette to measure 50 mL of the 4000 NTU
solution and pour it into a 250 mL measuring flask, and fill up to 250 mL meniscus)
The turbidity value (TURB) of this solution is equivalent to 800 NTU.
4. Dilute 800 NTU solution 10 times (use a pipette to measure 25 mL of the 800 NTU
solution and pour it into a 250 mL measuring flask, and fill up to 250 mL meniscus)
The turbidity value (TURB) of this solution is equivalent to 80 NTU.
5.
Dilute 80 NTU solution 10 times (use a pipette to measure 25 mL of the 80 NTU
solution and pour it into a 250 mL measuring flask, and fill up to 250 mL meniscus)
The turbidity value (TURB) of this solution is equivalent to 8 NTU.
Note
Instead of the standard solutions above, you can use other standard solutions of known
concentration measured with other standard instruments.

U-52, U-53, U-54 turbidity calibration
Set the number of calibration points.
You can set between 2 and 4 points.
1. Press the control unit’s CAL key to set the calibration mode.
2.
Press the down (

) key to move the cursor to "Manual Calibration", then press the
ENTER key.