Hanna Instruments HI93703-11 - 6.2. Log-On-Demand Data Storage

12
OPERATIONAL GUIDE
Even though HI93703-11 covers a very wide range of turbidity
values, for very accurate measurements of samples exceeding
40FTU*, Standard Methods require dilution. In such cases, the
correct amount of HI93703-0 or turbidity-free water to be added to
the sample can be calculated as follows:
Vos = 3000 / T
where:
Vos = volume of sample (mL) to be combined with HI93703-0 to
obtain the final volume of 100 mL.
T = HI93703 reading (exceeding 40FTU*)
E.g.: HI93703 reading = 200 FTU *
3000 / 200 = 15 mL (Vos)
15 mL (Vos)+85 mL (HI93703-0) = 100 mL
At this point, take a sample of this solution and measure its turbidity.
The correct turbidity value of the original sample will be:
T
n
x 100 mL / Vos = T
a
where:
T
n
= new HI93703 reading
T
a
= actual turbidity value of the original sample
E.g. If T
n
= 27 FTU *
T
a
= 27 FTU* x 100 mL / 15 mL = 180 FTU*
Note: Any sample taken above 1000 FTU will show out of range
by blinking “1000”.
6.2. LOG-ON-DEMAND
• After taking a reading, press the STO button. The last sample read
will be stored in memory. The display will also show on the bottom
right corner the reference number of the stored sample.
* 1 FTU = 1 NTU