2.3 Displays/Controls
Fig. 2.3.1 - Displays/Controls
1.
Display
Provides direct readout of pH, millivolts, temperature of
samples and standards and low battery indication.
2.
Function
Used for selection of mode of operation.
Switch
Off
- power off.
pH
- pH measurement based on last calibration (the adjustment
controls have no function).
pH Cal
- pH display based on settings of the adjustment
controls for buffer and slope.
°C
- displays the measured temperature if an ATC probe is
connected, or the manually adjusted temperature (set by the
Slope/Manual temperature control).
mV
- displays the electrode potential in mV.
3.
Buffer
Used to balance out the electrode offset between the pH
measurement cell and reference. This should be set with the
electrode immersed in pH7 buffer. This control adjusts the electrode effect
between -60mV to +60mV.
4.
Slope
Used to compensate for the variable sensitivity of pH
electrodes. As the electrodes age their sensitivity decreases
and this control is used to compensate for this. This control
adjusts the slope between 75% and 125% of Nernst.
5.
Manual Temp
When the °C mode is selected (without the ATC probe connected)
this control allows the compensation temperature to be set on the
display. This control becomes inoperative during use of the
ATC probe. The display will show the measured temperature if an ATC
probe is connected, or the manually adjusted temperature (set by the Slope/
Manual Temp control).
350 550/REV A/03-03
3
