Metrohm 781 pH/Ion Meter - Manual (Page 132)

8.4 Validation
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780/781 pH/Ion Meter, Manual
8.4 Validation
The checking and maintenance of the pH/Ion Meter can be carried out
in 3 steps. This list can be extended by the measures described in Sec-
tion 8.3.
1. Checking the electronic components when the instrument is
switched on.
2. Validation of the whole analytical system by wet chemistry.
3. pH/Ion Meter maintenance by Metrohm Service.
8.4.1 Electronic tests
After the pH/Ion Meter has been switched on an electronic system test
is carried out automatically. The following display is seen:
The tests are documented in the system test report; this can be printed
out when the instrument is switched on: (see Section 5.4):
'di
781 pH/Ion Meter 01104 5.781.0020
date 2004-05-21 15:32:00
RAM test OK
EPROM test OK
real time clock OK
COMPort OK
A/D converter OK
LCD display OK
==============
If one of these tests is not concluded with ' OK ' then please contact
Metrohm Service.
With a
real time clock error you can try resetting the date and time.
If the test is then ' OK ', you should check whether the stored methods
and instrument configuration are still unchanged.