16
Once calibrated by outside air, the analyzer is ready for use.
Note
− Outside air calibration of the analyzer may be cancelled before Step
3 by pressing
MODE
. The analyzer will go into the DOC measuring mode, retaining
the values of previous calibration coefficients.
2.3.5 Analyzer zero calibration
Analyzer zero calibration allows the sensor residual zero current to be com-
pensated within narrow limits (–3,0 to +3,0 µg/dm
3
).
Proceeds as follows prior to carrying out this operation:
switch on the analyzer;
prepare a fresh null solution as per para.2.3.3.2;
enable the DOC measuring mode in mg/dm
3
;
perform cycling operations as per para.2.3.3.3;
hold the sensor in the air for 5 min, submerge the sensor, with its mem-
brane down, in the null solution and move it to slightly agitate the solution in order
to prevent air bubbles from amassing on the membrane;
hold the sensor in the null solution for at least 40 min.
Perform the following steps to set the analyzer zero.
1
Press
CAL
. The analyzer display will show the
с0
caption.
2
Press
ENTER
. The analyzer display will show DOC
Z
0
readings in the null
solution without allowance for zero adjustment, e.g.
с.002 mg/dm
3
.
3
Wait at least
8 s
before pressing
ENTER
once again. The
donЕ
caption
will briefly appear on the display and the analyzer will go into the measuring mode.
The analyzer display will indicate a DOC value in the null solution after analyzer
zero setting:
0,000;
if
−0,003 mg/dm
3
≤ Z
0
≤ 0,003 mg/dm
3
;
Z
0
−0,003;
if
Z
0
> 0,003 mg/dm
3
;
Z
0
+0,003;
if
Z
0
< −0,003 mg/dm
3
.
Note
− Analyzer zero setting may be cancelled before Step 3, by pressing
MODE
. The analyzer will go into the DOC measuring mode, retaining the values of
previous calibration coefficients.
