Method for determining the pressure in a pressure measuring cell and measuring cell arrangement

Abstract

A method for determining the pressure in a pressure cell (2) and a measuring cell arrangement are described, wherein the method comprises determining a measurement signal (x) which is at least proportional to the pressure measured in the pressure cell (2) and filtering the measurement signal (x) with a first filter unit (10) having a low-pass filter characteristic to generate an output signal (y), wherein the low-pass filter characteristic of the first filter unit (10) is defined by a first damping factor (α1). The method is characterized in that an input difference (x_diff) derived from the difference between the output signal (y) and the measurement signal (x) is filtered with a second filter unit (20) having a low-pass filter characteristic to determine an output difference, wherein the low-pass filter characteristic of the second filter unit (20) is defined by a second damping factor (α2), and the first damping factor (α1) of the first filter unit (10) is determined based on the output difference of the second filter unit (20).

Description

Technical Field

[0001] The invention relates to a method for determining the pressure in a pressure cell and to a measuring cell arrangement. Background Art

[0002] It is known to measure pressure or pressure differential by applying pressure to a thin diaphragm and measuring the resulting deflection. A known and suitable method for measuring the deflection of such a diaphragm is to configure the diaphragm assembly as a variable capacitor, where the capacitance change, which is correlated to the pressure change, is evaluated by measuring electronics. The capacitor is constructed by placing a thin, flexible diaphragm surface at a small distance from the other side of the body and making the two opposing surfaces conductive. If the diaphragm and body are composed of non-conductive dielectric materials, these surfaces can be coated with a conductive layer, for example, to form capacitor electrodes. The diaphragm and / or body can also be made of conductive materials themselves, with these surfaces then forming capacitor electrodes. When pressure is applied to the diaphragm, the distance between the two electrodes changes due to the deflection, resulting in an evaluable capacitance change. For example, this type of sensor is manufactured in large quantities from silicon. In this case, both the planar substrate and the diaphragm are composed entirely of silicon. There are also embodiments with combined material compositions, such as silicon with a glass substrate. This allows for cost-effective sensor production. This type of pressure sensor can usually only be used from about 10 -1 The higher pressure range is in the range of millibars up to a few bars. -1 High resolution at lower pressures from mbar onwards is no longer achievable with silicon. Sensors of this type are not suitable for typical vacuum applications. Pressure measurements in vacuum are usually performed at atmospheric pressure and 10 -6 This measurement requires high sensitivity with good reproducibility and high resolution for vacuum pressure measurement, for which only specially designed measuring cells, which are designed in a completely different way from high-pressure measuring cells, can be used.

[0003] Capacitive diaphragm pressure measuring cells made of corrosion-resistant materials such as Al2O3 are particularly suitable for vacuum pressure measurement. EP 1070239 B1 describes a known capacitive vacuum measuring cell that is essentially entirely made of ceramic and is therefore highly corrosion-resistant. -6 For very low pressures of mbar, a very thin ceramic diaphragm is used, for example with a thickness of 60 μm, which is stress-free and symmetrically arranged in a ceramic housing.

[0004] In this case, the distance between the capacitor electrodes or diaphragm surface and the housing body surface is preferably in the range of 2 to 50 μm. The diameter of such a diaphragm pressure measuring cell is preferably in the range of 5 to 80 mm. The capacitance thus formed and to be measured is in the range of 10 pF to 32 pF. Thanks to new electronics, capacitances in the range of 5 pF to 1000 pF can now be measured. In this case, the measured capacitance serves as a measure of the pressure to be measured. When the diaphragm bends depending on the pressure, this capacitance changes accordingly, thereby enabling the pressure applied to the diaphragm to be detected. This capacitance measurement must be carried out very precisely and is not straightforward with small capacitance values, as the small capacitance results in an extremely small capacitance change caused by a pressure change. As a result, the electrical signal generated or derived thereby is also extremely small and therefore susceptible to interference.

[0005] Therefore, correspondingly high requirements are placed on the signal processing system for processing the pressure signal according to the above-mentioned embodiment. In addition, a filtering algorithm is used to optimize the characteristics of the measured pressure signal for further use, for example for controlling the pressure in the process chamber. Here, an attempt is made to describe a filtering algorithm that simultaneously achieves two contradictory goals for processing the pressure signal: First, the oscillation process should be ended as quickly as possible after a step-like change in the measurement signal, that is, the output signal of the filter should lead to a stable output signal as quickly as possible. As a result, the actions required in any case due to the pressure change can be started as quickly as possible. Secondly, possible noise signals should be suppressed as strongly as possible by the filtering algorithm. Therefore, according to the first condition, a filter that is as fast as possible is required, while according to the second condition, a slow filter is more desirable.

[0006] Many attempts are known to specify filtering algorithms and thus transfer functions of filters for processing measurement signals in order to achieve these two conflicting objectives. Known filtering algorithms are based on compromises that, in the present application, do not lead to satisfactory results when measuring pressure with highly sensitive sensors.

[0007] No. 5,838,599 describes a variant for a filter which allows both a short settling process in the case of rapid changes in the input signal and an effective reduction of noise signal components in the input signal in the settling state.

[0008] Reference is also made to US 2013 / 0016888 A1, which discloses a cost calculation method for eliminating noise using a linear filter.

[0009] Finally, a method is known from WO 2016 / 180547 A1, which describes two signal filters with different time constants and a switching mechanism. This switching mechanism causes a switch from one filter to the other in the signal path depending on the input signal or a change in the input signal. The switching mechanism is based on two functional blocks, "Fast" and "Slow." The "Fast" block detects rapid signal changes, while the "Slow" block identifies stable or slowly changing input signals. The time constant of the "Slow" block is, depending on the system, many times greater than that of the "Fast" block (typically a factor of 1,000). This is because a minimum number of measurement points must be analyzed in order to determine with sufficient reliability whether the signal is stable. Conversely, just one measured value is sufficient to detect a signal change. As a result, the known system according to WO 2016 / 180547 A1 behaves very unsatisfactorily when transitioning from a signal change (edge) to a stable value. Summary of the Invention

[0010] The object of the present invention is therefore to specify an improved method for processing measurement signals, in which a significant noise signal suppression is achieved but at the same time a rapid response to significantly changing measurement signals is possible.

[0011] This object is achieved by the features according to the invention. Advantageous embodiments and a measuring cell arrangement having a pressure measuring cell are explained in the following description.

[0012] The method according to the invention for determining the pressure in a pressure cell consists in

[0013] - determining a measurement signal which is at least proportional to the measured pressure in the pressure cell, and - filtering the measurement signal using a first filter unit having a low-pass filter characteristic for generating an output signal, wherein the low-pass filter characteristic of the first filter unit is defined by a first damping factor.

[0014] The method according to the invention is characterized in that

[0015] filtering the input difference derived from the difference between the output signal and the measurement signal for determining the output difference using a second filter unit having a low-pass filter characteristic, wherein the low-pass filter characteristic of the second filter unit is defined by a second damping factor, and

[0016] - determining a first damping factor of the first filter unit based on the output difference of the second filter unit.

[0017] An embodiment variant of the method according to the invention is characterized in that the first filter unit comprises a first exponential moving average filter.

[0018] Further embodiment variants of the method according to the invention are characterized in that the second filter unit comprises a second exponential moving average filter.

[0019] Other implementation variants of the method according to the invention are characterized in that the measurement signal is present as a time-discretely sampled measurement signal at a time point represented by a time index, and the output signal is also present as a time-discretely sampled output signal at a time point also represented by a time index, and the first and second filter units are implemented as time-discrete filters.

[0020] Other embodiment variants of the method according to the invention are characterized in that the low-pass filter characteristic of the first filter unit and / or the second filter unit is first-order.

[0021] Other embodiments of the method according to the invention are characterized in that the absolute value of the output difference is determined in an absolute value unit, the absolute value of the output difference is multiplied by a filter effect factor to determine a product, and the product of the multiplication is used to determine the first damping factor.

[0022] Other embodiment variants of the method according to the invention are characterized in that the product of the multiplication is limited to a value range of 0 to 1.

[0023] Other embodiments of the method according to the invention are characterized in that the absolute value of the output difference is exponentially squared before being multiplied by the filter effect factor.

[0024] Other embodiments of the method according to the invention are characterized in that the filter efficiency factor is between 0 and 10. 40 is within the value range of .

[0025] Other implementation variants of the method according to the invention are characterized in that the index is in the value range of 0 to 10, typically in the value range of 0.5 to 5, and more typically equal to 2.5.

[0026] Other implementation variants of the method according to the invention are characterized in that the second damping factor is in the value range of 0 to 1, typically in the value range of 0.05 to 0.25, more typically equal to 0.1.

[0027] Furthermore, the present invention relates to a measuring cell arrangement comprising a pressure cell and a diaphragm pressure measuring cell operatively connected to the pressure cell, the diaphragm pressure measuring cell generating a pressure-dependent measurement signal, the measurement signal being applied to a first filter unit having a low-pass filter characteristic for generating an output signal, wherein the low-pass filter characteristic of the first filter unit is defined by a first damping factor. The measuring cell arrangement according to the invention is characterized in that:

[0028] - an adding unit is present, to which the inverted input signal and the output signal are supplied for determining the input difference,

[0029] - applying the input difference to a second filter unit having a low-pass filter characteristic for determining the output difference, wherein the low-pass filter characteristic of the second filter unit is defined by a second damping factor, and

[0030] - applying the output difference and the second damping factor to the second filter unit for generating a first damping factor, the first damping factor being supplied to the first filter unit.

[0031] An embodiment variant of the measuring unit arrangement according to the invention consists in that the first filter unit comprises a first exponential moving average filter.

[0032] According to another embodiment variant of the measuring unit arrangement of the invention, the second filter unit comprises a second exponential moving average filter.

[0033] According to other embodiments of the measuring unit device according to the invention, the measurement signal is present as a measurement signal of time-discrete sampling at a time point represented by a time index, and the output signal is also present as an output signal of time-discrete sampling at a time point also represented by a time index, and the first and second filter units are implemented as time-discrete filters.

[0034] Further embodiment variants of the measuring unit arrangement according to the invention provide that the low-pass filter characteristic of the first filter unit and / or the second filter unit is first-order.

[0035] Another embodiment variant of the measuring cell arrangement according to the invention is that an absolute value unit is provided for determining the absolute value of the output difference, and the absolute value of the output difference and the filter effect factor are applied to the multiplication unit for determining the first damping factor.

[0036] According to a further embodiment variant of the measuring cell arrangement according to the invention, the first damping factor can be limited to a value range from 0 to 1 in the limiting unit.

[0037] A further embodiment variant of the measuring cell arrangement according to the invention consists in providing a function unit to which the absolute value and the exponent of the output difference are applied in order to generate the squared output signal.

[0038] According to another embodiment of the measuring unit device of the present invention, the filter effect factor is between 0 and 10. 40 is within the value range of .

[0039] Further embodiment variants of the measuring cell arrangement according to the invention provide that the index lies in the value range of 0 to 10, typically in the value range of 0.5 to 5, more typically equal to 2.5.

[0040] Further embodiment variants of the measuring cell arrangement according to the invention provide that the second damping factor lies in a value range from 0 to 1, typically in a value range from 0.05 to 0.25, and is more typically equal to 0.1. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, wherein:

[0042] Figure 1a and 1b A measuring cell arrangement is shown having a diaphragm pressure measuring cell connected to a process chamber, wherein a measurement signal is determined by means of the diaphragm pressure measuring cell and, after processing according to the invention in a signal processing unit, is supplied to a valve;

[0043] Figure 2 shows a block diagram according to a first embodiment variant of the present invention, which is particularly intended for implementation in a signal processing unit according to FIG. 1 ,

[0044] Figure 3 A block diagram of an exponential moving average filter, known per se as a first-order low-pass filter type as a time-discrete transfer function, is shown, which is used in particular for Figure 2 The first and / or second filter units are used, and

[0045] Figure 4 A block diagram shows a further embodiment variant of the present invention, which is intended in particular for implementation in the signal processing unit according to FIG. 1 . DETAILED DESCRIPTION

[0046] Figure 1aA highly simplified block diagram shows a measuring cell arrangement comprising a process chamber 1, a diaphragm pressure measuring cell 2, a vacuum pump 3, a signal processing unit 4, a control unit 5, a valve actuator 6, and a valve 7. The diaphragm pressure measuring cell 2 is used to determine the pressure in the process chamber 1, where a predetermined pressure is established according to the predetermined value of the vacuum process. Vacuum processes include a variety of methods, such as coating processes, etching processes, and heat treatment of workpieces. Vacuum processes often also utilize auxiliary gases, which are required both in an active manner as a reactive gas and in an inactive manner as an inert gas. For this purpose, gas is supplied to the process chamber 1 via a valve 7, which is actuated by the valve actuator 6. The valve can be used to control the gas flow and pressure in the process chamber 1. The diaphragm pressure measuring cell 2 generates a measurement signal x, which is processed in the signal processing unit 4 and the control unit 5 into a control signal s for the valve actuator 6. For precise process control, it is necessary that the diaphragm pressure measuring cell 2 measures as precisely as possible, but also rapidly, in order to be able to react as quickly and precisely as possible to pressure changes in the process chamber.

[0047] Figure 1b Show the basis Figure 1a Another simplified block diagram of the measuring unit arrangement, but now in the form of so-called "downstream pressure control" instead of "upstream pressure control". In downstream pressure control, the pressure gauge regulates the conductivity upstream of the vacuum pump via the adjustable inlet valve 8. Figure 1a The upstream pressure regulation shown in Figure 1b In the downstream pressure regulation shown in , the vacuum pump 3 is connected to the valve 7. In addition, the process chamber 1 is closed by an adjustable gas inlet valve 8. The gas required in the process chamber 1 is introduced into the process chamber 1 through the gas inlet valve 8 as required.

[0048] In a simplified embodiment of the present invention, it is also conceivable that the output signal y of the signal processing unit 4 is not used to control the pressure in the process chamber. This is not a closed system, but an open system. In this case, the pressure in any type of pressure cell (similar to the process chamber 1 according to FIG. 1 ) is measured using the pressure measuring unit 2 . The measurement signal x measured by the pressure measuring unit 2 is also processed in the signal processing unit 4 in order to obtain a stable, noise-free output signal y that nevertheless reacts quickly to changes.

[0049] From now on, considering again the embodiment variant according to FIG. 1 , the present invention relates to the processing of the measurement signal x in the context of the conditions prevailing in a vacuum process, and is primarily aimed at optimal signal processing of the measurement signal x, which may occur as a pressure signal in such a vacuum process. The signal processing in the signal processing unit 4 can, in principle, be performed in analog or digital form, wherein special precautions for analog or digital signal processing are not discussed further below, since such precautions (analog / digital conversion, filtering to avoid aliasing, selection of the sampling frequency, etc.) are sufficiently known to those skilled in the art.

[0050] The output signal y of the signal processing unit 4 is further processed in the control unit 5, for example using a so-called P controller, PI controller, PID controller or state controller. The controller implemented in the control unit 5 is responsible for the optimal tracking of the control signal s for the valve actuator 6 or valve 7.

[0051] In principle, the statements regarding the processes in the signal processing unit 4 and regarding its block diagrams apply both to the embodiment variant in a closed system and to the embodiment variant in an open system.

[0052] Figure 2 The processing steps according to the present invention, which are executed in the signal processing unit 4, are shown schematically and in a simplified manner. To implement the individual processing steps of the algorithm according to the present invention, which remains to be explained, a signal processor is used, for example, which is programmed accordingly. Of course, the signal processor can also perform other tasks, provided the processor capacity is sufficient for this purpose. In particular, it is conceivable that the controller of the control unit 5 is also implemented in the same signal processor.

[0053] As from Figure 2 As can be seen in FIG, the measurement signal x is fed to the first filter unit 10, which generates the output signal y. The first filter unit 10, with the measurement signal x and the output signal y, forms the actual signal path of the signal processing unit 4 ( FIG. 1 ). The remaining components, which remain to be explained, such as the second filter unit 20 and the adding unit 11, are provided to set the characteristics of the first filter unit 10.

[0054] The first filter unit 10 has a filter characteristic which is defined in a time-discrete system, for example, according to the following equation:

[0055] y k =(α·x k +(1-α)·y k-1

[0056] Here, y kis the time-discrete output signal, x k is a time-discrete measurement signal, k is a time-dependent index, and α1 is a variable whose value decisively determines the time constant of the first filter unit 10 and is also referred to as damping factor α1, for example. The object of the present invention is to optimally set the value of the damping factor α1, and more precisely to make the measurement signal x k Noise signals in the process chamber are suppressed as much as possible or even eliminated, but at the same time pressure changes in the process chamber 1 ( FIG. 1 ) are detected quickly so that a correspondingly rapid response can be achieved.

[0057] The aforementioned equation with the damping factor α1 has a low-pass filter characteristic as a filter characteristic for suppressing noise signal components, wherein the time constant for the first-order filter in the sampling interval T can be determined as follows:

[0058]

[0059] The choice of the value of the damping factor α1 is decisive for the present invention. k In the case of a stable pressure value containing only noise signals, the value of α1 is quite small, for example, 0.0001. k The noise signal in the filter is suppressed to the maximum, and the filtered output signal y k It is well suited for use in a regulator downstream of the control unit 5 ( FIG. 1 ), since the stable output signal leads to lower activity of the valve actuator 6 or valve 7 and thus to a reduced load on these components, so that their probability of failure is significantly reduced compared to known systems.

[0060] On the other hand, since the actual pressure change in the process chamber 1 (FIG. 1) should be detected without delay, the measurement signal x k This necessitates a different value for the damping factor α1, ie a value of α1 that is greater than 0.3, for example.

[0061] According to the invention, the adaptation of the value of the damping factor α1 is performed as a function of the difference between the output signal and the measurement signal. Starting from a time-discrete system in which the first filter unit 10 has a first-order low-pass filter according to the following formula,

[0062] y k =α1·x k +(1-α1)·y k-1 ,

[0063] The damping factor α1 is obtained by the input difference x_diff or in the case of a time-discrete system by x_diff k is determined, as from Figure 2 As can be seen in the simulation system shown in k-1 and x k The difference between is determined using the adding unit 11 as follows:

[0064] x_diff k =y k-1 -x k

[0065] Input difference x_diff k is supplied to the second filter unit 20, in which the first damping factor α1 is determined by the second damping factor α2. For example, the second filter unit 20 also has a first-order low-pass filter characteristic. Higher-order low-pass filter characteristics are also conceivable. In the case of a first-order low-pass filter characteristic, the equation can be applied in a time-discrete system:

[0066] α 1k =α2·x_diff k +(1-α2)·α 1k-1 , wherein a second damping factor α2 is predefined. The second damping factor α2 is, for example, in the range of 0 to 1, more specifically in the range of 0.05 to 0.25, and even more specifically equal to 0.1.

[0067] The following general situation is pointed out to technicians working in the technical field of filter design: whether in analog space or in time discrete space, the damping factor α of a filter, especially a first-order filter, can be directly calculated through the limit frequency f c To express and vice versa. In the case of sampling interval T, the following formula is obtained in the case of a first-order filter:

[0068]

[0069] Or conversely:

[0070]

[0071] This applies not only to the first filter unit 10 but also to the second filter unit 20 .

[0072] Figure 3 The block circuit diagram shows an exponential moving average filter, known per se, of the first-order low-pass filter type as a time-discrete transfer function. The following formula, already mentioned, applies:

[0073] y k =α·x k +(1-α)·y k-1, where k is an index in time (and correspondingly k-1 is a time point delayed by the sampling interval T), and α is the damping factor.

[0074] The above formula of the components yields the first and second adders 12, 13, the delay unit 15 and the damping unit 14. Figure 3 As shown in the block diagram, the output signal of the first adder 12 is multiplied by the damping factor α in the damping unit. The output signal of the damping unit 14 is applied to the second adder 13, in which the output signal is added to the delayed output signal y. k-1 Add to generate the output signal y k Finally, by transforming the input signal x k The output signal y is delayed inversely with k-1 The signals are added together to form the output signal of the first adder 12 .

[0075] Figure 3 The block diagram of the exponential moving average filter shown in FIG. 1 is in principle applicable both to the first filter unit 10 and to the second filter unit 20 .

[0076] Figure 4 Another embodiment variant of the present invention is shown again with the aid of a block diagram. k is then loaded into the first filter unit 10 to generate the output signal y k Here again, the first filter unit 10 has a first-order low-pass filter characteristic, although higher-order filters can also be used.

[0077] As in reference Figure 2 As in the first embodiment variant of the invention already described, an adding unit 11 is provided, wherein the output signal y is converted into a summation unit 11. k-1 Subtract the input signal x from k To generate the input difference x_diff k . Input difference x_diff k is in turn applied to the second filter unit 20. In this case, the second filter unit 20 again has a first-order low-pass filter characteristic, wherein higher-order filters can also be used here.

[0078] Figure 4 A further embodiment variant of the invention shown in FIG. 1 now consists in, on the one hand, transforming the output difference y_diff determined by the second filter unit 20 into k Loaded into the absolute value unit 30 where y_diff is determined k The absolute value of |y_diff k |.absolute value|y_diff k| is loaded into the function unit 31, in which a function in the general form of a polynomial is applied to the absolute value |y_diff k |. A simplified function is, for example, the following function implemented in the function unit 31:

[0079] z k =|y_diff k | exp

[0080] wherein the exponent exp is, for example, in the range from 0 to 10, typically in the range from 0.5 to 5, or even more typically equal to 2.5. It goes without saying that if exp=1, then

[0081] z k =|y_dif f |,

[0082] according to Figure 4 The implementation variant is thus transformed into a variant according to Figure 2 , in which the functional unit 31 can be regarded as not present.

[0083] Output value Z k The sum of the filter effectiveness factor FW is supplied to a multiplication unit 32, in which a multiplication is performed to determine the product p k , the product p k is supplied to the limiting unit 33 to be limited to a value in the range of 0 to 1. The first damping factor α1 of the first filter unit 10 is thereby determined.

[0084] The function executed in the restriction unit 33 can be formally described as follows:

[0085]

[0086] It has been shown that the filter efficiency factor FW can be between 0 and 10 40 Free choice within the range.

[0087] Finally, the second damping factor α2 is chosen in the range of 0 to 1, typically in the range of 0.05 to 0.25, more typically equal to 0.1.

[0088] Therefore, according to Figure 4 The embodiment variant of comprises three predefinable parameters: the filter effect factor FW, the second damping factor α2 and the exponent exp.

[0089] Of the three predeterminable parameters, the filter effectiveness factor FW and the exponent exp are particularly important. These two parameters significantly influence the filter performance: the filter sensitivity can be adjusted via the exponent exp, while the filter effectiveness (as the name suggests) can be adjusted via the filter effectiveness factor FW, with the filter effectiveness factor FW influencing the noise component in the signal.

[0090] Reference numerals:

[0091] 1 processing room

[0092] 2-diaphragm pressure measuring cell

[0093] 3 Vacuum pump

[0094] 4 signal processing units

[0095] 5Control Unit

[0096] 6-valve actuator

[0097] 7 valves

[0098] 8 intake valves

[0099] 10First filter unit

[0100] 11 Addition Unit

[0101] 12 First adder

[0102] 13 Second adder

[0103] 14 damping units

[0104] 15 delay units

[0105] 20 Second filter unit

[0106] 30 absolute value units

[0107] 31 function units

[0108] 32 multiplication units

[0109] 33 Restriction Unit

[0110] xMeasurement signal

[0111] y output signal

[0112] s control signal

[0113] x_diff Input difference

[0114] y_diff output difference

[0115] α damping factor

[0116] α1, α2 first and second damping factors

[0117] FW filter effect factor

[0118] exp index

[0119] z k The squared output signal.

Claims

1. A method for determining the pressure in a pressure cell (2), wherein the method comprises - determining a measurement signal (x) which is at least proportional to the measured pressure in the pressure cell (2), and - filtering the measurement signal (x) using a first filter unit (10) having a low-pass filter characteristic for generating an output signal (y), wherein the low-pass filter characteristic of the first filter unit (10) is defined by a first damping factor (α1), characterized in that - filtering an input difference (x_diff) derived from the difference between the output signal (y) and the measurement signal (x) using a second filter unit (20) having a low-pass filter characteristic for determining an output difference (y_diff), wherein the low-pass filter characteristic of the second filter unit (20) is defined by a second damping factor (α2), and - determining a first damping factor (α1) of the first filter unit (10) based on the output difference (y_diff) of the second filter unit (20).

2. The method according to claim 1, characterized in that The first filter unit (10) includes a first exponential moving average filter.

3. The method according to claim 1 or 2, characterized in that The second filter unit (20) includes a second exponential moving average filter.

4. The method according to claim 1 or 2, characterized in that The measurement signal (x) is a temporally discrete sampled measurement signal (x) at a time point represented by a time index (k). k ) exists, and the output signal (y) is also a time-discrete sampled output signal (y) of the time point represented by the time index (k) k ) exists, and the first and second filter units (10, 20) are implemented as time-discrete filters.

5. The method according to claim 1 or 2, characterized in that The low-pass filter characteristic of the first filter unit (10) and / or the second filter unit (20) is first-order.

6. The method according to claim 1 or 2, characterized in that The output difference (y_diff) is determined in the absolute value unit (30). k ) and the absolute value of the output difference (y_diff k ) is multiplied by the absolute value of the filtering effect factor (FW) to determine a product, and the product of the multiplication is used to determine the first damping factor (α1).

7. The method according to claim 6, characterized in that The product of the multiplication is constrained to be in the range of 0 to 1.

8. The method according to claim 6, characterized in that Before being multiplied by the filter effect factor (FW), the output difference (y_diff k ) is raised to the power of the exponential (exp).

9. The method according to claim 6, characterized in that The filter efficiency factor (FW) is between 0 and 10. 40 is within the value range of .

10. The method according to claim 8, characterized in that The exponent (exp) ranges from 0 to 10.

11. The method according to claim 10, characterized in that The exponent (exp) ranges from 0.5 to 5.

12. The method according to claim 10, characterized in that The exponent (exp) is equal to 2.

5.

13. The method according to claim 1 or 2, characterized in that The second damping factor (α2) is in the value range of 0 to 1.

14. The method according to claim 13, characterized in that The second damping factor (α2) is in the value range of 0.05 to 0.

25.

15. The method according to claim 13, characterized in that The second damping factor (α2) is equal to 0.

1.

16. A measuring cell arrangement comprising a pressure cell (2) and a diaphragm pressure measuring cell operatively connected to the pressure cell (2), wherein the diaphragm pressure measuring cell generates a pressure-dependent measurement signal (x), which is applied to a first filter unit (10) having a low-pass filter characteristic for generating an output signal (y), wherein the low-pass filter characteristic of the first filter unit (10) is defined by a first damping factor (α1), and wherein: - an adding unit (11) is present, to which the inverted input signal (x) and the output signal (y) are supplied for determining the input difference (x_diff), - applying the input difference (x_diff) to a second filter unit (20) having a low-pass filter characteristic for determining an output difference (y_diff), wherein the low-pass filter characteristic of the second filter unit (20) is defined by a second damping factor (α2), and - applying the output difference (y_diff) and the second damping factor (α2) to the second filter unit (20) for generating a first damping factor (α1), which is fed to the first filter unit (10).

17. The measuring unit device according to claim 16, characterized in that The first filter unit (10) includes a first exponential moving average filter.

18. The measuring unit device according to claim 16 or 17, characterized in that: The second filter unit (20) includes a second exponential moving average filter.

19. The measuring unit device according to claim 16 or 17, characterized in that: The measurement signal (x) is a temporally discrete sampled measurement signal (x) at a time point represented by a time index (k). k ) exists, and the output signal (y) is also a time-discrete sampled output signal (y) of the time point represented by the time index (k) k ) exists, and the first and second filter units (10, 20) are implemented as time-discrete filters.

20. The measuring unit device according to claim 16 or 17, characterized in that: The low-pass filter characteristic of the first filter unit (10) and / or the second filter unit (20) is first-order.

21. The measuring unit device according to claim 16 or 17, characterized in that: There is an absolute value unit (30) for determining the output difference (y_diff k ) and the absolute value of the output difference (y_diff k ) and the filter effect factor (FW) are loaded into a multiplication unit (32) for determining a first damping factor (α1).

22. The measuring unit device according to claim 21, characterized in that The first damping factor (α1) can be limited to a value range from 0 to 1 in a limiting unit (33).

23. The measuring unit device according to claim 21, characterized in that Set up a function unit (31), load the output difference (y_diff) into the function unit k ) and the exponential (exp) to generate the squared output signal (z k ).

24. The measuring unit device according to claim 23, characterized in that The filter effect factor (FW) is between 0 and 10. 40 is within the value range of .

25. The measuring unit device according to claim 24, characterized in that The exponent (exp) ranges from 0 to 10.

26. The measuring unit device according to claim 25, characterized in that The exponent (exp) ranges from 0.5 to 5.

27. The measuring unit device according to claim 25, characterized in that The exponent (exp) is equal to 2.

5.

28. The measuring unit device according to claim 16 or 17, characterized in that The second damping factor (α2) lies in a value range of 0 to 1.

29. The measuring unit device according to claim 28, characterized in that The second damping factor (α2) is in the value range of 0.05 to 0.

25.

30. The measuring unit device according to claim 28, characterized in that The second damping factor (α2) is equal to 0.1.

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