Excavating
Patent
1996-07-17
1998-10-13
Palys, Joseph
Excavating
371 70, G06F 1100, G06F 1116
Patent
active
058225145
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/NL95/00354 filed Oct. 16, 1995.
The present invention relates to a method for processing signals in a protection system.
The invention furthermore relates to a device for carrying out said method.
In the known protection systems a certain amount of input signals, in particular the course of time of pulsed input signals, is usually monitored by means of protection circuits or security circuits, the output signals of which are in turn also monitored. Usually the signals to be monitored exhibit a certain dynamic (time behaviour) and the protection circuits do not have to take action until the moment that the behaviour, in particular the time behaviour, of the signals to be monitored has changed. When an output signal level remains constant, for example because of the occurrence of a system error in the protection system, and cannot even be changed, this (stuck at) error will not be detected until changes are purposefully made on the input of the protection system as a check.
In addition it is not possible to establish the occurrence of such a function allocation error on for example both input signals being logical one, when an "OR" function is erroneously carried out instead of an "AND" function, until the moment that one of the signal levels of said input signals is changed. There is a very real possibility of such an error occurring when a protection system is required to be programmable in order to enhance its flexibility and usability.
Under certain circumstances the occurrence of an unsafe situation, even if this is caused by a complex of, possibly simultaneously occurring, errors, is not detected by means of a so-called "voter circuit", which decides whether an unsafe situation has occurred on the basis of a majority decision of the signal levels of the signals to be monitored.
It will be apparent that the non-detection of potentially dangerous error situations which may occur in protection systems is undesirable.
Consequently the object of the present invention is to provide a method and a device for processing signals in a protection system, which not only makes it possible to monitor the signal levels of the input signals as well as their timing, but which in addition to that is capable of detecting errors occurring in the device itself which cannot be directly detected at the output thereof, and to make said errors detectable in a manner whereby the system itself, in spite of the error that is occurring, is put in a safe condition.
In order to accomplish that objective the invention comprises the features defined in claim 1.
The advantage of the method according to the invention is that the execution of complementary operations makes it possible to relate the result of said operations unequivocally to each other, so that, for example when the (interim) results of the operations are the inverse of each other, the results related to each other provide information with regard to the correct functioning of the protection system in a simple manner. At the same time said (interim) results, which are of importance for the protective function when using the method according to the invention, can be used for executing the operations on the input signals in order to obtain output signals, which thus automatically comply with very strict safety and reliability requirements. Advantageous is furthermore the fact that the occurrence of an error situation can be detected without running the risk that the processing of the signals will introduce errors which remain unnoticed for a sufficiently long period to be of importance to safety.
One embodiment of the method according to the invention comprises the feature defined in claim 2.
The advantage of the embodiment according to the invention is that the possible occurrence of an error is established within a (usually short) period, and that corrective measures can be taken at once, if desired.
Another embodiment of the method according to claim 3 has the advantage that if the (interim) results of the complementary operations do not c
REFERENCES:
patent: 3174133 (1965-03-01), Kunzman et al.
patent: 3340506 (1967-09-01), Mayer
patent: 3618020 (1971-11-01), Parker
patent: 3719816 (1973-03-01), Darmon et al.
patent: 4166272 (1979-08-01), Deck
patent: 4302841 (1981-11-01), McCulloch
patent: 4584666 (1986-04-01), Zolnowsky et al.
patent: 4740972 (1988-04-01), Rutherford, Jr.
patent: 4785453 (1988-11-01), Chandran et al.
patent: 5179689 (1993-01-01), Leach et al.
patent: 5327543 (1994-07-01), Miura et al.
patent: 5535417 (1996-07-01), Baji et al.
Dassel Johannes Roland
Steinz Hendrik Christian
NV GTI Holding
Palys Joseph
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