Metrohm 817 Bioscan - Manual (Page 71)

5.4 Instrument test with the dummy cell
817 Bioscan
63
5.4 Instrument test with the dummy cell
If any interference occurs whose source is suspected to lie in signal re-
cording or transfer you can selectively check the instrument electronics
and the connection to the PC. This is done by connecting the
6.2813.030 Dummy Cell supplied instead of the built-in flow-through
measuring cell. The temperature in the 817 Bioscan should be kept
constant (30 °C) and, for optimal shielding, the front door should be
closed.
This dummy cell contains a resistor (300 M
Ω) and a condenser (0.47
µF) connected in parallel. If a voltage of 0.8 V is applied in the DC mode
then a current of 2.67 nA (
± 1%) is measured at this cell. The condenser
functions as a noise generator and simulates the capacitance of a well-
functioning measuring cell.
Please make the following settings in IC Net:
If you use these settings to record a baseline ( Control / Startup hard-
ware (Measure baseline )) you should see a smooth signal line at 2.67
nA. Even at maximum magnification the noise should not exceed 0.01
nA.