Commissioning
Proline Promag 55 PROFIBUS PA
76
Hauser
6.4.2
Advanced diagnostic functions
With the aid of the optional software package "Advanced Diagnostics" (F-CHIP, accessories
Page 99), changes in the measuring system can be detected early on, e.g. as a result of build-up
(coating) or corrosion at the measuring electrodes. Such factors cause a reduction in accuracy under
normal circumstances, or cause system errors in extreme cases.
With the aid of diagnostic functions it is possible to record different diagnostic parameters during
operation – e.g. electrode potential of measuring electrodes 1 and 2, decay time of test pulses at
electrodes 1 and 2 (as a measure of possible build-up) etc. By analyzing general trends in these
measuring values, deviations in the measuring system relative to a "reference condition" can be
detected early on, and the necessary measures can be taken.
!
Note!
Further information on this can be found in the "Description of Device Functions" manual.
Reference values as a basis for the analysis of general trends
In order to analyze general trends, reference values for the appropriate diagnostic parameters are
required. These values must be obtained under reproducible and constant conditions. Such
reference values are first recorded during factory calibration and stored in the device. However,
reference data should also be collected under customized process conditions, e.g. during
commissioning or immediately afterwards. The reference values are always recorded and saved in
the measuring system via the REFERENCE STATUS USER (7501) function.
"
Caution!
It is not possible to analyze general trends in diagnostic parameters without reference values.
Reference values should always be obtained immediately after commissioning. This ensures that the
reference values saved are values pertaining to the "original condition" of the measuring system i.e.
without the influence of any build-up or corrosion.
Type of data collection
Diagnostic parameters can recorded in two different ways which you can set using the
ACQUISITION MODE (7510) function:
• Selection PERIODICAL: Data acquisition is performed periodically by the device. The
ACQUISITION PERIOD (7511) function is used to enter the desired time interval.
• Selection MANUAL: Data is collected manually by the user at any chosen points in time.
!
Note!
The last 10 (via display) or 100 (via FieldCare with the Flow Communication FXA193/291 DTM
and Fieldsafe Module) recorded diagnostic parameter values are saved chronologically in the
measuring system. The "history" of these parameter values can be retrieved using the following
functions:
Triggering warning messages
A limit value may be assigned to all diagnostic parameters if necessary. If this limit value is exceeded,
a warning message is triggered
→
WARNING MODE function (7503).
The limit value is entered into the measuring system as an absolute (+/–) or relative deviation
compared to the reference value
→
WARNING function (75...).
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
Lowest measured value
→
MINIMUM VALUE function
Highest measured value
→
MAXIMUM VALUE function
List of the last 10 (or 100) measured values
→
HISTORY function
Measured/reference value deviation
→
ACTUAL DEVIATION function
* Further information on this can be found in the "Description of Device Functions" manual.
