Metrohm 916 Ti-Touch - Manual (Page 359)

￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
28 Parameters
916 Ti-Touch
￭￭￭￭￭￭￭￭ 343
Table 11 Possible errors during the electrode test
Test criterion Message Remedy
Buffer pH 9:
The drift in stirred solution is > 1 mV.
General problem ￭ Connect an electrode.
￭ Replace the defective electrode
cable.
￭ Clean the diaphragm (see leaflet
for the electrode).
￭ Replace the electrode.
Buffer pH 9:
–10 mV < U(not stirred) < 10 mV
and
The sum of the drift values after 1, 2,
3 and 4 min is < 12 mV/min.
Short circuit Replace the electrode.
A response time does not fulfill the
limit value for the rating Usable
electrode. Glass membrane / Diaphragm Clean the diaphragm (see leaflet for
the electrode).
The pH values are not defined for all
the buffers at the temperature mea-
sured. No buffer data Repeat the electrode test at a tem-
perature at which the pH values of
all the buffers are defined.
All the slopes fulfill the limit values
for the rating Usable electrode.
and
Uoff is outside the preset limits.
Unsuitable reference electrode ￭ Repeat the electrode test with a
suitable reference system.
￭ Replace the contaminated refer-
ence electrolyte.
￭ Select Electrode type = Cus-
tom and adjust the limits for
Uoff.
The streaming potential is too high. Contaminated diaphragm Clean the diaphragm (see leaflet for
the electrode).
Two slopes do not fulfill the limit val-
ues for the rating Usable electrode. Wrong buffer Repeat the electrode test with buf-
fers pH 4, 7 and 9.
All the slopes do not fulfill the limit
values for the rating Usable elec-
trode. Partial short circuit ￭ Check the temperature sensor.
￭ Enter the correct calibration tem-
perature.