Hach 1950Plus, Инструкция по эксплуатации инструмента, Страница: 98 / 188

Page 98
Calibration Menu
UVTOCOperation.fm
Section 6
TOC mg/L. Three of the calibrations, the primary calibration, the manual
calibration, and the auto calibration are two point calibrations as described
above. Ideally they would be all be the same data points, however minor
variations will exist due to tolerances. These calibrations should also all yield
a result of the same gain (slope). The fourth calibration is a multiple point
calibration arrived at by measuring the CO
2
ppm produced by more than two
standards, one of them always being the zero.
Primary Calibration and Manual Calibration
Primary and Manual Calibration are identical supervised calibrations that are
run by the operator. The distinction between the two is that a primary
calibration should be performed only after the peristaltic or lamp has been
replaced, when the analyzer will have the best performance and theoretical
gain. A successful primary calibration will automatically update the manual
calibration data set as well as the primary calibration data set.
Auto-calibration
This scheduled calibration sequence is automatically carried out by the
analyzer. Zero and span standards are automatically drawn from the ports
as required, to determine the auto-calibration data set. A successful
auto-calibration will become the active calibration.
Multi-point calibrations
The three forms of multi-point calibrations are detailed in
section 6.10.7 on
page 102 .
Active calibration
This is the calibration data set used to calculate the TOC during an online
TOC measurement. The primary, manual, autocalibration or multipoint
calibration may be manually set to be the active calibration.
The successful completion of any type of calibration will result in the
calibration being used as the active calibration and the entry in the manual
control/active calibration screen will be changed to reflect the type of
calibration just completed.
Active calibration versus primary calibration % (Prim v cal)
This is the ratio of the gains of the active calibration set to the gain of the
primary calibration set expressed as a percentage. The deviation from 100%
will identify the change in analyzer gain.
If the active calibration set gain:
g
a
=
is compared to the primary gain
g
p
= as a percentage,
the result is:
After a primary calibration, this percentage will always be 100% because the
active calibration is the primary calibration. If manual calibration is selected, it
will still be 100% as the primary calibration copies to the manual calibration
set. Only following the next calibration will the result be different. Thus a
y
2a
y
1a
–
( )
x
2a
-------------------------------
y
2p
y
1p
–
( )
x
2p
-------------------------------
100 g
a
•
g
p
----------------------
100 x
2p
•
y
2a
y
1a
–
( ) •
x
2a
y
2p
y
1p
–
( ) •
--------------------------------------------------------------- =