wtw AmmoLyt 700 IQ, Руководство по эксплуатации

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AmmoLyt
®
700 IQ Calibration and measuring
4 - 1 ba75353e05 03/2006
4 Calibration and measuring
4.1 Calibration
4.1.1 General information
Why calibrate? When an ammonium electrode is operated its characteristic curve
changes with the course of time. The characteristic curve is generally
characterized by the slope and the axis intercept. The characteristic
curve is the base for calculating the measured value from the electrode
voltage.
With calibration, the current characteristic curve parameters are deter-
mined as follows:
!
With all calibration procedures, i.e. 1-point and 2-point procedures,
the change of the axis intercept is determined ("drift potential").
!
All two-point calibration procedures additionally determine the
slope.
Why calibrate? Calibrate during the initial commissioning, after exchanging an elec-
trode and at regular intervals (depending on the application).
Calibration log and
calibration history
The calibration history contains the calibration log of the initial and last
of the following calibrations. You can call up the calibration history via
the
Calibration history of selected sensor display option.
Citation form There are two common citation forms for the specification of ammo-
nium contents in a solution. The citation form NH4 specifies the ammo-
nium content (NH
4
+
). The citation form NH4-N specifies the amount of
ammonium nitrogen only. You can select the required citation form in
the settings for the sensor.
If the citation forms do not correspond, you can carry out the conversion
yourself.
1 mg/l NH4 = 0.777 mg/l NH4-N.
1 mg/l NH4-N = 1.287 mg/l NH4.
Note
Ordering information on ammonium standard solutions can be found in
section 6.2.