Endress+Hauser Proline Promag 55, Руководство по эксплуатации

Страница: 73 / 120

Proline Promag 55 FOUNDATION Fieldbus Commissioning
Hauser 73
6.3.5 Advanced diagnostic functions
Using the optional software package "Advanced Diagnostics" (F-CHIP, accessories
→
ä
79),
changes in the measuring system can be detected early, e.g. changes due to buildup or corrosion on
the measuring electrodes. Such factors usually reduce the accuracy of measurement or, in extreme
cases, result in system errors.
Using diagnostic functions, it is possible to record different diagnostic parameters during operation
– e.g. electrode potentials of measuring electrodes 1 and 2, decay times for test pulses at electrodes
1 and 2 (as an indicator of possible buildup) etc. By analyzing trends in these measured values,
deviations in the measuring system compared to a "reference status" can be detected early and the
necessary measures taken.
!
Note!
Further information on this can be found in the "Description of Device Functions" manual.
Reference values as the basis for trend analyses
For trend analyses, reference values must always be recorded for the relevant diagnostic parameters.
These must be determined under reproducible and constant conditions. These reference values are
recorded for the first time during calibration at the factory and are stored in the measuring device.
However, reference data should also be collected under customer-specific process conditions, e.g.
during commissioning or directly afterwards. The recording and saving of reference values in the
measuring system is always performed using the REFERENCE STATUS USER (7501) device
function.
"
Caution!
An analysis of trends in diagnostic parameters without reference values is not possible! Reference
values should always be determined directly after commissioning. This ensures that the saved
reference values are values in the "original status" of the measuring system - i.e. which have not yet
been influenced by existing buildup or corrosion.
Type of data collection
There are two different ways to record diagnostic parameters, and you can set these in the
ACQUISITION MODE (7510) function:
• PERIODICAL option: Data acquisition is carried out periodically by the measuring device. The
desired time interval is entered using the ACQUISITION PERIOD (7511) function.
• SINGLE SHOT option: Data acquisition is carried out manually by the user at arbitrary points in
time.
!
Note!
In the measuring system, the last 10 diagnostic parameter values recorded are stored in
chronological order. The "history" of these parameter values can be called up using different
functions:
Diagnostic parameters of the
function groups * Saved data records (for each diagnostic parameter)
COATING 1
COATING 2
ELECTRODE POTENTIAL 1
ELECTRODE POTENTIAL 2
VOLUME FLOW
NOISE VALUE Reference value
→
REFERENCE VALUE function
Actual value
→
ACTUAL VALUE function
Smallest measured value
→
MINIMUM VALUE function
Highest measured value
→
MAXIMUM VALUE function
List of the two (or hundred) previous measured values
→
HISTORY function
Deviation, measurement/reference
→
ACTUAL DEVIATION function
* Further information on this can be found in the "Description of Device Functions" manual.