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
0.200 mg/L chlorine and a representative lot
of reagent, an operator obtained with a single
instrument a standard deviation of 0.004 mg/L.
Range
0.000 to 0.500 mg/L
Resolution
0.001 mg/L
Accuracy
@25 °C (77 °F)
±0.020 mg/L ±3% of reading
Light Source
Tungsten lamp
Light Detector
Silicon Photocell with narrow band interference filter @525 nm
Method
Adaptation of the Standard Method 4500‑Cl G. The reaction between
free chlorine and DPD reagents causes a pink tint in the sample.
Environment
0 to 50 °C (32 to 122 °F);
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 x 2.7”)
Weight
320 g (11.3 oz.).
Required Reagents
Code
Description
Quantity/test
HI95762‑0
DPD Powder reagent
1 packet
SPECIFICA
TIONS
PRECISION AND ACCURACY
