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
calibration OK
Monitoring cal.interval expired
These messages can normally be removed by pressing the
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 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.