DE2610759C3 - Circuit arrangement for counting runs of a variable to be monitored by a predetermined value - Google Patents

Description

State

Further developments of the invention are the subject of the subclaims.

An embodiment of the invention is described below with reference to the figures. It shows

F i g. 1 shows a circuit arrangement for counting runs of a variable to be monitored a predetermined value,

F i g. 2 shows the mode of operation of the circuit arrangement according to FIG. 1 clarifying diagram and

3A to D signal curves in the FIG circuit arrangement shown.

In the circuit arrangement according to FIG. 1, a sensor It is provided, which at its output 12 a emits electrical voltage proportional to a variable, which can be an acceleration, for example. Of the Sensor 11 can therefore be an accelerometer or some other type of stress evaluation Be a device, such as a strain gauge. The voltage appearing at the output 12 becomes an input 13 of a matching amplifier 1 ″ supplied

The voltage given at the amplifier output 16 on ait line 15 characterizes the variable to be monitored, e.g. B. an acceleration or a stress. The line 15 is routed to a first input 17i, 17 ₂ , etc. of a number of electronic voltage comparators 18 |, 18j, etc., the number of which corresponds to the number of values for which the number of runs on the part of the variable to be monitored, e.g. B. the acceleration, is to be determined, on the condition that this variable finally assumes or has already assumed a further predetermined larger or smaller value for each of the values mentioned

In the case of aircraft, for example, it can be determined how often the so-called "load multiple" has the value 3g, Ag, 5g, 6g, Sg (g = acceleration due to gravity), but under the condition that a lower value then occurs, for example 2g. In Figure 2 a diagram is shown in which the abscissa represents time and the ordinate the load factor indicating the point A corresponds to the beginning of a maneuver that starting at the point A curve shows that the load factor to a point B increases rapidly between a value 5g and Sg , after which there is again a drop to point C , where a value smaller than g is reached. Then there is another rise to point D, which is above 6 ^, then a fall to point E, which lies between Ag and 5g . Then the curve rises again to a point Fan, which lies between 5g and % g , and then drops to point G , which corresponds to a negative g value. After that, the curve is close to zero, and so on.

The in Fig. The embodiment shown in FIG. 1 is constructed in such a way that it can be determined how often the acceleration assumes the value 3g under the assumption that it then reaches a value smaller than 2g in each case. Further, it can be determined how many times the acceleration assumes the value of Ag, with the proviso that they each _s then a value smaller than # 2 reach etc

In the exemplary embodiment shown, the circuit arrangement contains five signal channels, of which only two are shown, each corresponding to a value of a first number of values 3g, Ag, 5g and 8 ^, and the counting of the processes in which the variable to be monitored is one assumes these values is only carried out when the variable to be monitored subsequently reaches the value 2g . This applies to all values of the first number mentioned.

The second input 19i of the voltage comparator 18 is connected to a terminal 211 of a first voltage divider circuit 22i, which has two series-connected resistors Ri and R \ . The connection point 23i of these two resistors is connected to the terminal 211 via a line 24], ίο the second Terminal of resistor R \ is connected to ground potential, while the second terminal of resistor R \ is connected to a reference voltage source 26 via a line 25i

The line 24i is also connected to ground potential via a circuit 27i which contains a third resistor R "\ and an electronic switch 28i

For example, if the channel Vj with a value Zg

is controlled, the values of the resistors R \ and R't are selected so that the voltage at the input 19 | is equal to the voltage at Eii ^ ang \ 7 \ when the acceleration value detected by the sensor 11 becomes equal to 3g . A signal appears at output 32 | for this value of the voltage comparator 18i, which is fed to the electronic switch 28i via a signal path 33i, so that the latter is closed.

The value of the resistor R "\ is chosen so that the voltage comparator 18] resumes its first state when the value 2g is reached when the acceleration drops. This then opens the electronic switch 28i again

The signal appearing at the output 32r of the voltage comparator 18j has the form shown in FIG. 3A. The leading edge / corresponds to the closing of the electronic switch 28i and thus the switching on of the resistor R "\ in the voltage divider 22 _t , the trailing edge / 'corresponds to the opening of the electronic switch 28 :.

The output 321 of the voltage comparator 18 | is with input 34 | a differentiating circuit 35] which emits pulses at its output 36i which characterize the edges / and / 'and which are shown in FIG. 3B. The circuit 35i is connected to a discriminator 37) which has the positive or negative polarity of the circuit shown in FIG. 3B indicating signals. The discriminator 37i is followed by a signal shaping circuit 38), the output of which emits a signal whose course is shown in FIG. 3C for positive output signals and in FIG. 3D for such negative output signals from the discriminator 37] is switched one step further when the acceleration i-; r decreases the load multiple after a value of 3g to the value of 2g

The second sianal Vj is analogous to the first channel V \

built up, but the values of the resistors /? 2 and R 2 are selected, for example, so that they correspond to a value Ag for the acceleration. In the one shown in FIG. 1

In the exemplary embodiment shown, the value of the third resistor R ″ i of the second voltage divider circuit 22z is selected so that the counter 39 continues to check the acceleration through the same low value 2g as for the counter 39.

t> 5.

According to another embodiment, the value for the resistor R "j can be selected so that the condition for the further counting of the states of the

The passage of ^ is different from the condition that applies to the further counting of the states of the passage of the acceleration through 3g .

To carry out a test method, the matching amplifier 14 is, for example, via a second input 51 is supplied with a voltage which changes according to a predetermined law, namely initially rising up to the maximum value to be expected for the variable determined with the sensor 11 and then decreasing to the expected minimum value. So one can take into account the at this Check with the various counters 39 obtained counting results of the proper state of the Determine circuit arrangement.

For this purpose 2 sheets of drawings

Claims (8)

Patent claims: 1. Circuit arrangement for counting runs of a variable to be monitored, represented by a voltage, through a first predetermined value, with a voltage comparator, at one input of which is to be monitored Voltage is applied and its other input with a supplying the first predetermined value Reference voltage source is connected, and with a counting device for counting signals emitted by the voltage comparator, characterized by a switching device (28i, 33 |) for alternating switching of the Output of the reference voltage source (22i) between the first predetermined value and a second predetermined value when the variable to be monitored passes through the respective one of the Reference voltage source (22t) supplied value and through eist signal shaping circuit (35i-38i) Formation of a counter event only during the switching of the output of the reference voltage source (22,) to one of the two possible values. Circuit arrangement according to Claim 1, characterized in that the reference voltage source contains a voltage control circuit (R ₁ ', R'y, R' \) whose division ratio can be switched between two values as a function of an output signal from the voltage comparator (18) 3. Circuit arrangement according to claim 2, characterized in that the voltage divider circuit (Ru R'v, R "i) contains a resistor (R",) which depends on an output: ingss. '<Inal of the voltage comparator (18 |) by means an electronic switch (28i) can be switched on or off 4. Circuit arrangement according to claim 2 or 3, characterized in that between the voltage comparator (18]) and the counting device Differentiator (35i) is provided 5. Circuit arrangement according to one of the preceding claims, characterized in that the voltage comparator (18 |) is connected in parallel with further voltage comparators (I82) acted upon by the variable to be monitored, each of which also has a reference voltage source (222), a switching device (282), a signal _{shaping circuit (35 2} , 37 _2> 38z) and a counter (39 ₂ ) are assigned. 6. Circuit arrangement according to claim 5, characterized in that the resistors (R ") which can be switched on by the output signal of the voltage comparators (18) are selected so that matching counting conditions exist for the various counting devices (39). 7. Circuit arrangement according to claim 5, characterized in that the resistors (R ") which can be switched on by the output signal of the voltage comparators (18) are selected so that different counting conditions exist for the various counting devices (39). 8. Circuit arrangement according to one of claims 2 to 7, characterized in that the Voltage divider (22) are connected to a common voltage source (26). The invention relates to a circuit arrangement according to the preamble of claim 1. In the field of surveillance e.g. B. more mechanical Occasionally, the requirement that To count occurrences of exceeding a predetermined value by a monitored variable. this can happen depending on the fact that the named size after passing through the predetermined value for example, a lower one, also passed assumes correct value This is especially the case Case when it comes to the evaluation of stresses to which an object or a mechanical arrangement is exposed, or if an object or mechanical arrangement is i ^ experiences accelerations A circuit arrangement of the type mentioned, which z. B. from DE-OS 24 21 843 is known previously used to determine the mechanical load on parts of a mechanical structure, in particular the mechanical load that an aircraft exerts due to acceleration forces is exposed So far one has tried to use these forces in the way determine that one runs one for the occurring forces by a representative size predetermined value does not count around several passes with a small fluctuation in electrical Size to count the predetermined value, it has been proposed to use a delay circuit. the. This has the disadvantage that major changes to the electrical variables that are within the delay time cannot be counted. Furthermore such delay circuits are relatively expensive. ', Furthermore, DE-OS 23 34 350 deals with the problem of determining the maximum amplitude of an oscillation sequence. A method for precisely counting significant changes in an electrical quantity is not given. From US-PS 28 79 053 egg-ie circuit arrangement is known with which the exceeding of certain discrete values are counted by a variable to be monitored under the secondary condition that the variable after reaching these values again a certain Baseline Assumes It is suitable for use in an accelerometer but works with mechanical contact switching in the event of a change in acceleration, which then actuates relays, which in turn each control a counter. Apart from that of high mechanical and electrical effort works this circuit with regard to the in connection with the acceleration and BeIas'ungsmess z. B. to be provided for aircraft Requirements too imprecise. It is the object of the invention to provide a circuit arrangement that can be implemented with the least possible outlay and works more precisely than previous devices while avoiding mechanical elements This task is carried out by the Claim 1 mentioned features solved According to the invention is therefore dependent on the to counting states a circuit is controlled, which assumes a first switching state when the to monitored variable reaches a first value, while it assumes a second state when the Quantity reaches a second value This circuit may contain a counter that counts how often said circuit is the first or the second