Xylem CG 839 - Manual (Page 6)

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6 pH-measurement with combination pH-electrode and
separate temperature sensor Pt 1000
pH-measurement with automatic temperature-compensation is possible too using a combination pH-
electrode and a separate Pt 1000 temperature sensor. In this case, connect one plug of the temperature
sensor to the socket marked Pt 1000 and connect the other plug to the reference electrode socket.
7 pH-measurement with manual temperature compensation
When using an electrode without integrated temperature sensor (e. g. combination pH-electrode type
no. N 62), the manually set temperature is shown in the display together with the message <<°C man>>.
This temperature value can be adjusted with the keys < > and < > to correspond to the actual
measuring temperature. Manual temperature adjustment is not possible in the <>-function and no
temperature is indicated in the display.
8 mV-measurement
Press the - key to switch the Microprocessor pH Meter CG 839 to the <>-function. The
<>- function display lights up.
Dip the electrode combination (e. g. the combination Pt-electrode, type no. Pt 62, for redox voltage
measurements) into the sample solution. The digital display shows the resulting reading directly in mV.
9 Temperature measurement
Dip the Pt 1000 temperature sensor or the combination electrode type no. N 2042 A (with integrated
temperature sensor) into the sample medium.
The display shows the temperature reading. The simultaneously displayed pH- or mV-value is of no
significance if only the temperature sensor is connected.
10 Hold function
Press the - key to hold the readings. The message <> appears in the display. Press the
- key to switch the Microprocessor pH Meter CG 839 back to the normal measuring mode.
11 Automatic switch-off
The Microprocessor pH Meter CG 839 switches itself off automatically 60 minutes after the last keypress.
To override this automatic switch-off function, switch-on the Microprocessor pH Meter CG 839 with the
- key whilst simultaneously holding the key and depressed. Only the message
<> appears in the display as acknowledge. The Microprocessor pH Meter CG 839 is ready for
making measurements after pressing the - key again. The automatic switch-off function is always
disabled in <> mode of the Microprocessor pH Meter CG 839.
12 Reset function
If the Microprocessor pH Meter CG 839 gives incorrect readings or displays for no apparent reason, the
Microprocessor pH Meter CG 839 must be switched-off. Then press the -key and the - key
at the same time. Only the message <> appears in the display. The Microprocessor pH Meter
CG 839 is ready for making measurements after pressing the - key again. After switching-on in
this way, the Microprocessor pH Meter CG 839 is set to 98 % slope and zero-point pH = 7.00. A new
calibration with the electrode is necessary if the actual electrode characteristic differs from these values.