Metrohm 756 KF Coulometer - Manual (Page 119)

5.5 Testing the measuring input
756/831 KF Coulometer, Instructions of Use 111
5.5 Testing the measuring input
With the aid of the "767.0010 Calibrated Reference for mV, pH, Ω , uS, °C" you can check
the measuring input "Ipol" and the indicator electrode cable.
If a Remote Box is connected:
Deactivate the Remote Box (key <Config>,
>peripheral units
,
Remote Box: off
). Switch
the Coulometer off and screw off the Remote Box. Switch the Coulometer on again (so
that the new configuration will be recognized).
Procedure:
1. Switch off Coulometer.
2. Screw off indicator electrode cable and insert in socket 5 of the 767. The cover re-
mains closed on the 767.
3. Switch on Coulometer and press key <9> at the same time. The display shows:
diagnose press key 0...9
4. Press key <6>. The display shows:
pol/ADC test press 1..3
5. Press key <3>. The display shows:
polarizer test
6. Press <ENTER> on the Coulometer. The display shows:
dummy resistor 10.0 k ?
Press <ENTER> and enter the resistance from the cover of the 767 ( Ω -value 5). The
display shows:
polarizer test *
When the test has been completed the display shows:
polarizer test o.k.
7. Exit the diagnostic program with 3 times <CLEAR>.
8. Make the Coulometer ready for work again:
. Screw the cable back on to the indicator electrode.
. Plug in the cable of the generator electrode.
The measuring input and cable have now been checked.