Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Mechanical measurement system
Reexamination Certificate
1999-02-17
2001-05-15
Hoff, Marc S. (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Mechanical measurement system
C702S182000, C702S187000, C073S579000, C235S375000
Reexamination Certificate
active
06233527
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a system for monitoring units excited by oscillations, having the features stated in the preamble of claim
1
.
It is known from U.S. Pat. No. 4,612,620 to monitor units excited by oscillations by means of a so-called route. For the purposes of the present description, units excited by oscillations are understood to mean one or more machines, production installations, auxiliary devices, components or other installations of any kind which are to be regarded in a certain association with one another, for example that they all belong to one and the same plant. The route comprises defined measuring points being allocated a measuring task in a specific sequence within a specific period of time at the units. For this purpose, a portable measuring apparatus is provided, having operator-control elements, memories, microprocessors and a display. Measuring tasks relevant for each ofthe possible measuring points can be stored with associated, suitable measurement settings in this measuring apparatus via a higher-level computer (central processing unit). Consequently, a specific measurement, for example frequency analyses of oscillations etc., can be carried out at each measuring point by means of this portable measuring apparatus. The measurement results thus obtained are stored in the portable measuring apparatus. Once the route has been patrolled, the portable measuring apparatus can be connected again to the higher-level computer, whereupon an evaluation of all the stored measurement results of all the measuring points allocated a measuring task takes place.
Consequently, it is a principal characteristic of the route that the measuring tasks are stored in the sequence of later processing in the central processing unit and that this sequence is transmitted to the measuring apparatus, so that the measuring tasks are automatically displayed in the prescribed sequence in the measuring apparatus.
It is known to use as measuring tasks the measuring of individual measured variables for an assessment of the state of the unit having the measurng points. These individual measured variables are not specific to the respective measuring points, but are regularly recorded according to the route laid down and, after transferring the measurement results into the central processing unit, are supplied with regard to a trend in the development of the measurement results and/or to a threshold-value comparison. Since, as is known, an actual identification of the cause of an error can only take place by means of a signal measurement, preferably with specialists being able to assign specific lines in recorded frequency spectra to specific causes of error in the evaluation. To carry out these signal measurements, a second patrol of the route is required, in order that the signal measurements can be carried out at those measuring points determined with the first patrol of the route at which the evaluation of the individual measured variables which have been measured indicates that a threshold value had been exceeded. To be able to carry out this second patrol of the route, a listing of specific measurement settings of the signal measurements by a specialist is required, either at the central processing unit or in situ, at the respective measuring point on the measuring apparatus.
A further known route comprises carrying out complete signal measurements at each selected measuring point of the route, without an assessment of the state of this measuring point having taken place beforehand using an individual measured variable. Since the signal measurements for monitoring units excited by oscillations, for example a frequency analysis, are relatively complicated, the measuring apparatus must have a correspondingly great capacity. In particular, there must be sufficient storage space for storing the measuring tasks, the measuring programs and the measurement results; what is more, a relatively complex software package must be kept for the proper processing of these points.
SUMMARY OF THE INVENTION
The invention is therefore based on the object of specifying a system of the generic type which does not have these disadvantages.
This object is achieved according to the invention by a system having the features stated in claim
1
. The fact that in the central processing unit there is stored for each of the measuring points a standard measuring task and at least one extended measuring task, which are loaded into the measuring apparatus according to the selected route, only the standard measuring task being carried out at the measuring points and at least one of the extended measuring tasks being automatically displayed and carried out at the relevant measuring point as a function of the occurrence of a registrable event which can be assigned to the unit having the measuring point, and the fact that the measurement results of the standard and extended measurements carried out are transferred into the central processing unit and evaluated there, make it advantageously possible to defme in advance for each measuring point an at least two-stage error profile, with which the measuring apparatus is activated according to the measuring points located on the route laid down, the error profiles comprising a simple classification of the measurement results to prescribed categories, an alarm signal being generated if a defined category is exceeded within the error profile and the at least one extended measuring task, preferably a signal measuring task, only then being automatically carried out for this measuring point.
It is possible to permit operator control which does not require a specially trained specialist. In particular by virtue of the division into at least two-stage measurement, the first measurement preferably merely comprising the recording of a simple individual characteristic value, handling is very simple. Only when, within this individual characteristic value, there is recorded at the measuring point a signal which falls into a predefined category which is not to be exceeded is the alarm signal triggered, so that the operator perceives acoustically and/or visually that there is possibly an error at this measuring point. This message at the same time initiates an actual analysis of the measuring point with the measurement at the higher stage, that is to say the at least one signal measurement stored in the measuring apparatus for this actual measuring point takes place.
In a preferred development of the invention it is provided that, in the measurement of the individual characteristic value within the standard measurement, at least one threshold value, preferably three threshold values, are stored for each individual characteristic value for the automatic identification of an error or of a deterioration in state. Consequently, the division of the measured individual characteristic values takes place into four categories, which are respectively separated by the threshold values and respectively correspond to an error profile.
Altogether, the system according to the invention provides simple operator control for a measuring apparatus and the processing or evaluation ofthe route in the central processing unit, so that a specialist only has to be kept on standby, that is to say only need be used in an acute case. As a result, there is a saving in qualified expert personnel, since the latter no longer has to carry out the routine processing of the predefined route, since experience shows that there is no error message at the vast majority of measuring points. At the same time, the storage capacity of the measuring apparatus and the storage capacity of the central processing unit can be kept smaller, since the signal measuring tasks are processed, and corresponding results have to be stored, only in an acute case. Finally, the route has to be patrolled only once in order to carry out the standard measurement and, if appropriate, an extended measurement (signal measurement).
Furthermore, in a preferred development of the invention it is provide
Bühler Steffen
Franke Dieter
Weichselbaumer Martin
Bui Bryan
Hoff Marc S.
Nixon & Peabody LLP
Pruftechnik Dieter Busch AG
Safran David S.
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