AMI INSPECTOR pH
Maintenance
A-96.250.761 / 161017 33
6.5. Quality Assurance of the Instrument
Every SWAN on-line instrument is equipped with integrated, auton-
omous quality assurance functions to survey the plausibility of each
measurement.
For AMI pH-Redox these are:
continuous monitoring of sample flow
continuous monitoring of the temperature inside the transmit-
ter case
Further a manual, menu driven inspection procedure can be carried
out using a certified reference instrument. Running at the same
sampling point as an inspection equipment, the AMI Inspector pH
verifies the measuring results. After enabling the quality assurance
procedure by defining the quality assurance level, the instrument
reminds the user periodically to run the procedure and results are
stored in a history for review.
Quality assur-
ance level
Central feature of the quality assurance function is the assignment
of the monitored process to a Quality assurance level.
There are three predefined levels plus a user level. Hereby the in-
spection interval, the deviation limits of temperature and measuring
result between the inspection equipment and the monitoring instru-
ment are defined.
Level 1: Trend; Measurement used as an additional informa-
tion to follow the process indicating trends.
Level 2: Standard; Monitoring of several parameters of a pro-
cess (e.g. oxygen, hydrazine and pH in feedwater). In case of
instrument failure, other parameters can be used for process
monitoring.
Level 3: Crucial; Monitoring of critical processes, value is
used for control of another part or subsystem (valve, dosing
unit, etc.).
Additional level:
Quality level 4: User; User defined inspection interval, maxi-
mal deviation of temperature and measuring result.
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