LaMotte LTC3000wi Turbidity & Chlorine Lab Meter - Manual (Page 7)

Auto Shut-off: 5, 10, 30 min, disabled
Power Source † : USB wall adapter, USB computer connection or
lithium ion rechargeable battery 2200 mAH, 3.7V
Battery Life: ~380 tests (backlight on) to 1000 tests
(backlight off)
(with signal averaging disabled)
Electrical
Ratings:
Provided on nameplate label
Dimensions: (W x L x H) 8.84 x 19.05 x 6.35 cm; 3.5 x 7.5 x 2.2
inches
Weight: 362 g, 13 oz (meter only)
USB Interface: mini B
† CE Mark: The device complies to the product specifi cations for the Low
Voltage Directive.
 STATISTICAL & TECHNICAL DEFINITIONS RELATED
TO PRODUCT SPECIFICATIONS
Method Detection Limit (MDL): “The method detection limit (MDL)
is defi ned as the minimum concentration of a substance that can
be measured and reported with 99% confi dence that the analyte
concentration is greater than zero and is determined from analysis of
a sample in a given matrix containing the analyte.” 1 Note that, “As Dr.
William Horwitz once stated, ‘In almost all cases when dealing with
a limit of detection or limit of determination, the primary purpose of
determining that limit is to stay away from it.’” 2
Accuracy: Accuracy is the nearness of a measurement to the accepted
or true value. 3 The accuracy can be expressed as a range, about the
true value, in which a measurement occurs (i.e. ±0.5 ppm). It can also
be expressed as the % recovery of a known amount of analyte in a
determination of the analyte (i.e. 103.5 %).
Resolution: Resolution is the smallest discernible difference between
any two measurements that can be made. 4 For meters this is usually
how many decimal places are displayed. (i.e. 0.01). Note that the
resolution many change with concentration or range. In some cases
the resolution may be less than the smallest interval, if it is possible to
make a reading that falls between calibration marks. A word of caution,
that resolution has very little relationship to accuracy or precision. The
resolution will always be less than the accuracy or precision but it is
not a statistical measure of how well a method of analysis works. The
resolution can be very, very good and the accuracy and precision can
be very bad! This is not a useful measure of the performance of a test
method.
Repeatability: Repeatability is the within-run precision.
5 A run is a
single data set, from set up to clean up. Generally, one run occurs
on one day. However, for meter calibrations, a single calibration is
considered a single run or data set, even though it may take 2 or 3 days.
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