6
Precision
is how closely repeated measurements
agree with each other. Precision is usually expressed
as standard deviation (SD).
Accuracy
is defined as the nearness of a test result
to the true value.
Although good precision suggests good accuracy,
precise results can be inaccurate. The figure
explains these definitions.
In a laboratory using a standard solution of
1.00 mg/L chlorine and a representative lot
of reagent, an operator obtained with a single
instrument a standard deviation of 0.02 mg/L.
SPECIFICA
TIONS
PRECISION AND ACCURACY
Range
0.00 to 5.00 mg/L
Resolution
0.01 mg/L from 0.00 to 3.50 mg/L;
0.10 mg/L above 3.50 mg/L
Accuracy
@25
°
C (77
°
F)
±0.03 mg/L ±3% of reading
Light Source
Tungsten lamp
Light Detector
Silicon Photocell with narrow band interference filter @525 nm
Method
Adaptation of the EPA DPD method 330.5 and Standard Method
4500-Cl G. The reaction between free chlorine and the DPD reagent
causes a pink tint in the sample.
Environment
0 to 50 ºC (32 to 122 ºF); max 95% RH non-condensing
Battery Type
9V (1 pc.)
Auto-Shut off
After 10` of non-use in measurement mode;
after 1 hour of non use in calibration mode;
with last reading reminder
Dimensions
192 x 104 x 69 mm (7.6 x 4.1 x2.7”)
Weight
320 g (11.3 oz)
REQUIRED REAGENTS
Code
Description
Quantity/test
HI93701-0
DPD Powder Reagent
1 packet
