Metrohm 781 pH/Ion Meter - Manual (Page 125)

8 Troubleshooting – Messages – Maintenance
780/781 pH/Ion Meter, Manual
115
Problem Possible cause Remedy
With standard addition
'auto' the potential step
'delta U' is not reached Streaming potential of the
measuring or reference elec-
trode causes potential differ-
ence between addition in stirred
and measurement in unstirred
solution
• Lower dosing rate
• Increase stirring rate
• Increase 'delta U'
• 'auto dos' instead of 'auto'
System test message:
system error #X Instrument fault
• Note error number and inform
Metrohm Service
8.2 Messages
The pH/Ion Meter uses various messages to selectively inform you
about possible errors or operating problems. These are shown in the
bottom line of the display and illustrated by a symbol in front:
Type Symbol Example of a message
Error same buffer
Warning cal.data out of limits
Information manual stop
change buffer <ENTER>
calibration OK
Monitoring cal.interval expired
These messages can normally be removed by pressing the <QUIT>
key. However, some messages will remain until their cause has been
remedied. For example, this applies to a monitoring message or a
warning message during a standard addition run. In the latter case it is
necessary to carry out a new and successful analysis to remove such a
warning message.
Please note that you should not press <QUIT> to acknowledge a
message while a report is being produced as this will cancel the re-
port.
The following table lists all the messages which could appear on the
display of the pH/Ion Meter.