Emerson Rosemount Clarity II T56, Справочное руководство

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A Verify linearity
This procedure describes how to verify linearity between turbidity and TSS.
Procedure
1. Collect a sample of the process liquid.
You may need 10 L or more if you use the Rosemount ™ Clarity II for measuring
turbidity. If you uses a laboratory turbidmeter, you will need less volume. The
Rosemount Clarity II requires about 500 mL for the measurement; laboratory
turbidmeters require 50 mL or less. Verify that the turbidity of the sample is less
than 200 NTU. Store in a clean bottle.
2. Filter a portion of the sample to obtain at least 5 L of dilution liquid.
The filtrate is needed to dilute the sample in subsequent steps. Verify that the
turbidity of the dilution water is low. If filtering the sample is impractical, use
deionized water for dilution.
3. Measure the total suspended solids (TSS) in the sample obtained in Step 1 .
Thoroughly mix the sample before withdrawing liquid.
A magnetic stirrer is best, but inverting the sample repeatedly for about a minute
works too. Avoid violent shaking or mixing. Refer to any standard reference work on
water and wastewater testing for the procedure for determining TSS.
4. Dilute the sample from Step 1 by a factor of 0.9, 0.7, 0.5, 0.3, and 0.1.
See the table for recommended volumes. Measure TSS and turbidity for each
dilution. For lower TSS values, use a larger volume of sample.
Dilution factor Volume of stock, mL Final volume, mL Volume for
Rosemount Clarity II,
mL Volume for TSS, mL
1.00 -- -- 500 50 - 250
0.9 900 1000 500 50 - 250
0.7 700 1000 500 50 - 250
0.5 500 1000 500 50 - 250
0.3 300 1000 500 50 - 250
0.1 100 1000 500 50 - 250
5. Plot the data obtained in Step 4 , with turbidity on the Y-axis and TSS on the X-axis.
Fit the best straight line to the data.
6. Locate two points (P1 and P2) on the line separated as much as possible. Read the
ppm and NTU value for each point and enter these into the transmitter.
Reference Manual Verify linearity
00809-0100-3565 July 2020
Rosemount T56 59