YOKOGAWA RC400G, Руководство пользователя

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<7. Calibration>
7-6
IM 12F4A1-01E
(4) Set the residual chlorine concentration value of the calibrating standard solution.
First, measure residual chlorine concentration of the calibrating standard solution by manual
analysis. In principle, perform measurement using amperometric titration (AT method).
Note: Yokogawa employs amperometric titration for calibration.
On pressing [>] key, the most significant digit of the displayed value flashes indicating that
input is possible. Select the digits whose numeric values are to be changed using [>] key
and change the values using [Λ] and [v] keys.
(5) After equalizing the displayed value to the residual chlorine concentration of the calibrating
standard solution, execute span calibration.
Press [ENT] key. During the calibrating operation, <CAL> lamp flashes. Calibration is
performed when the analyzer stabilizes so that predetermined conditions are met after
measured value stability is automatically checked.
When calibration is executes, the value displayed in the data display flashes once and, at
the same time, flashing <CAL> lamp extinguishes.
(6) Now the span calibration is completed.
Remove the tube used for calibration and transfer the “sample water/standard solution”
selector valve to the “sample water” position.
If error message “Err22” <failure> is detected in span calibration, this calibrating operation
becomes invalid. Recalibrate span exercising care for correct entry of calibration standard
solution residual chlorine concentration.
“Err22” is detected when the ratio of measured sensitivity to the reference sensitivity is less than
0.5. The reference sensitivity set on shipment is the value of “2.62 µA/mg/l at 20 °C” based on
amperometric titration.
When the standard solution residual chlorine concentration is measured using manual analysis
other than amperometric titration (colorimetry, iodometric titration, etc.), if span calibration cannot
be executed by more accurate measurement, change the reference sensitivity to meet the
manual analytical method employed.
Reference sensitivity changing method is two-fold: predetermined reference sensitivity manual
entry and automatic change by span calibrating operation.
For reference sensitivity manual entry, specify function code “4” in <PROGRAM.1> mode.
Perform key operation for entry referring to subsection 5.3.4 (2).
For automatic change, perform span calibration with function code “d” in <MAINT.> mode. (See
subsection 5.3.3 (3).)
14th Edition : Jul. 15, 2020