LaMotte 2020i Turbidimeter - Manual (Page 35)

Header M e n u T i t l e
Message or Result
Window
M e s s ag e
o r R e s u l t
Menu Selection Window * F i r s t C h o i c e
~
€
Footer 1 6 : 0 2 : 1 9 0 1 / 0 4 / 0 5
S e c o n d C h o i c e
a n o t h e r
a n d s o o n
As described previously, the
button allows an exit or escape from the current menu
and a return to the previous menu. This allows a rapid exit from an inner menu to the
main menu by repeatedly pushing the
button. Pushing OFF at any time will turn the
2020 off.
The display may show the following messages:
E r r 1 t o E r r 7 Error messages. See Trouble Shooting Guide. (page 30)
l o w b a t t e r y Low battery
>
Over range indicator.
pq
More choices are available and can be viewed by scrolling up
and/or down through the display.
Header Identifies the current menu and information on units and
reagent systems if applicable. In the data logging mode the
number of the data point is displayed and the total number of
data points in the memory will be shown.
Footer Shows current time and date.
Negative Results
There are always small variations in readings with analytical instruments. Often these
variations can be observed by taking multiple readings of the same sample. These
variations will fall above and below an average reading. Repeated readings on a 0.00
sample might give readings above and below 0.00. Therefore, negative readings are
possible and expected on samples with concentrations at or near zero. This does not
mean there is a negative concentration in the sample. It means the sample reading
was less that the blank reading. Small negative readings can indicate that the sample
was at or near the detection limit. This is a normal variation that results in a negative
reading. A large negative reading, however, is not normal and indicates a problem.
Some instruments are designed to display negative readings as zero. In this type of
instrument, if the meter displayed zero when the result was actually a large negative
number there would be no indication that a problem existed. For this reason, the 2020
displays negative numbers.
DISPLAY & MENUS 35