Method and apparatus for detecting defects in a control unit housing
By using sensors to detect and analyze humidity dynamics within control device housings, the method effectively identifies defects like leaks, ensuring the safety and reliability of control devices by adapting to external humidity changes.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-08-26
- Publication Date
- 2026-03-11
AI Technical Summary
Conventional methods for detecting defects in control device housings, particularly leaks, are unreliable due to temperature nonuniformities inside the housing, which are not identified by existing humidity sensors, leading to inaccurate identification of housing damage.
A method and device that utilize a first sensor to detect air humidity inside the housing, determine the dynamics of humidity based on a characteristic parameter, and compare it with predetermined thresholds to reliably identify defects by evaluating the time variation of humidity, optionally incorporating external humidity changes using a second sensor to enhance detection accuracy.
This approach allows for the reliable identification of housing defects, such as leaks, by quickly adapting to humidity changes, thereby preventing water ingress and enhancing the safety and reliability of control devices.
Smart Images
Figure 2026042761000001_ABST
Abstract
Description
[Technical Field]
[0001] Conventional technology The present invention relates to a method and device for detecting defects, in particular leaks, in the housing of a control device, and to a vehicle including such a device. [Background technology]
[0002] Humidity sensors are used in various electronic devices in vehicles to increase the safety of their use. Direct limits for relative air humidity are useful for identifying condensation. The relative air humidity assessment is performed locally at a single humidity sensor location. Because the temperature uniformity inside the electronic device's housing is unknown, localized condensation, such as condensation on a cooling body whose temperature is below the dew point, can occur. Therefore, the occurrence of condensation does not necessarily mean that the electronic device's housing is damaged. Temperature nonuniformities are not identified by the sensor, and identifying housing defects is unreliable. Summary of the Invention [Problem to be solved by the invention]
[0003] It is therefore desirable to be able to reliably detect defects, particularly leaks, in the housing of a control device. [Means for solving the problem]
[0004] Disclosure of the Invention This is achieved by the method, the device and the vehicle according to the independent claims.
[0005] A method for detecting defects, particularly leaks, in a housing of a control device includes detecting a first characteristic quantity characterizing the humidity of the air inside the housing, determining a parameter characterizing the dynamics of the humidity of the air inside the housing based on the first characteristic quantity, and comparing the parameter with at least one predetermined threshold or a predetermined valid range, where a housing defect is detected if the parameter exceeds or falls below the at least one threshold or valid range. By evaluating the dynamics of the humidity inside the housing, a housing defect can be reliably identified. In the presence of a housing defect, the humidity inside the housing more quickly adapts to changes in the humidity of the air outside the housing. This reliably identifies the housing defect and triggers an event that allows a user or a computing unit to recognize the presence of the defect. This increases the safety of use of the control device, for example, by preventing damage to electronic devices caused by water entering through the defect.
[0006] Preferably, the parameter maps the time variation of the first characteristic value, in particular the time derivative of the first characteristic value, thereby enabling variations in air humidity inside the housing to be efficiently determined.
[0007] Preferably, the first characteristic value is relative air humidity. A first characteristic value in the form of relative air humidity can be provided inexpensively using a simple sensor. Many control devices already have a sensor that detects a signal that characterizes the relative air humidity inside the control device's housing.
[0008] For example, the valid range is defined by an upper limit selected from a range between 10 and 15% / h. This upper limit is based on the inventor's testing of this type of control device and characterizes a change in relative air humidity of 10 to 15% within one hour. A positive rate of change characterizes an increase in relative air humidity inside the housing and occurs when the relative air humidity outside the housing is higher than the relative air humidity inside the housing. A negative rate of change characterizes a decrease in relative air humidity inside the housing and occurs when the relative air humidity outside the housing is lower than the relative air humidity inside the housing.
[0009] In an advantageous embodiment, the method comprises detecting a second characteristic value characterizing the air humidity outside the housing and determining a parameter depending on the first and second characteristic values, the parameter being a time constant for each individual housing characterizing a change in the first characteristic value, in particular the change in the air humidity inside the housing. The air humidity outside the housing is not constant but changes when the control device moves, especially if the control device is installed in a vehicle. The movement of the control device also creates a cooling effect from the surrounding air. Using the second characteristic value, the influence of the air humidity outside the housing is incorporated into the determination of the parameter. This ensures that defects in the housing are detected even when the difference between the air humidity outside the housing and the air humidity inside the housing is small.
[0010] Preferably, relative air humidity is used as the first characteristic value and the second characteristic value. A signal characterizing the relative air humidity can be provided using a low-cost sensor.
[0011] Preferably, a housing defect is detected when the parameter falls below at least one predetermined threshold, e.g., 7.0 h or 6.9 h. This threshold is based on the inventor's tests using a type of control device for a steer-by-wire steering system. Over time, a homogeneous equilibrium is reached between the relative air humidity inside the housing and the relative air humidity outside, similar to gas exchange, heat exchange, or the charging and discharging process of a capacitor. If a leak occurs as a defect, the larger the leak, the faster this equilibrium is reached. The smaller the time constant for each individual housing, the larger the housing leak or defect.
[0012] The device according to the present invention for detecting defects, in particular leaks, in a housing of a control device comprises a first sensor device configured to detect a first characteristic quantity characterizing the air humidity, in particular the relative air humidity, inside the housing of the control device, an optional second sensor device configured to detect a second characteristic quantity characterizing the air humidity, in particular the relative air humidity, outside the housing of the control device, and a calculation unit configured to carry out the method according to the above embodiment.
[0013] A vehicle according to the present invention includes a control device with a housing and a device according to the above embodiment.
[0014] Preferably, the control device is a control device for a steer-by-wire steering system.
[0015] In a further aspect, a method for determining at least one threshold and / or valid range for the method described above comprises providing a relative air humidity inside a space, providing a relative air humidity inside a chamber, the chamber being arranged in the space, the relative air humidity inside the chamber being higher than the relative air humidity inside the space, placing a series of test control devices inside the space, the residence time of the control devices inside the space being selected in particular so that the value of the relative air humidity inside the housing of the control devices is at least 95% of the value of the relative air humidity inside the space, and placing the control devices from the space into the chamber, the residence time of the control devices inside the chamber being selected in particular so that the value of the relative air humidity inside the housing of the control devices is at least 95% of the value of the relative air humidity inside the space. a control device disposed in the space from the chamber, the residence time of the control device in the space being selected in particular so that the value of the relative air humidity inside the housing of the control device is at least 78% of the value of the relative air humidity inside the space; detecting the relative air humidity inside the space, the relative air humidity inside the chamber, and the relative air humidity inside the housing of the control device; and determining a time constant for at least one individual one of the control device housings depending on the detected relative air humidity inside the space, the relative air humidity inside the chamber, and the relative air humidity inside the housing of the control device. This method allows for efficient identification of effective thresholds and / or effective ranges for different types of control devices or different control device housings.
[0016] Preferably, the method comprises setting at least a threshold value and / or a valid range for the method described above in dependence on a time constant for the identified at least one individual one of the housings of the control device.
[0017] Further advantageous embodiments will become apparent from the following description and drawings. [Brief explanation of the drawings]
[0018] [Figure 1] 1 is a flowchart of a method for detecting defects in a housing of a control device. [Figure 2] 1 is a schematic diagram of an apparatus for detecting defects in a housing of a control device. [Figure 3] 1 shows some of the progression of the relative air humidity inside the housing for different defects; [Figure 4a] FIG. 1 is a schematic diagram of the test setup. [Figure 4b] 1 is a test flowchart. DETAILED DESCRIPTION OF THE INVENTION
[0019] Fig. 1 shows a flowchart of a method 100 for detecting a defect 26, in particular a leak, in the housing 32 of the control device 30 shown in Fig. 2. The method 100 includes detecting 102 a first characteristic quantity 22 characterizing the air humidity 50 inside the housing 32 and determining 104 a parameter 24 characterizing the dynamics of the air humidity 50 inside the housing 32 as a function of the first characteristic quantity 22. The method 100 further includes comparing 106 the parameter 24 with at least one predetermined threshold value 106a or a predetermined valid range 106b, where a defect 26 in the housing 32 is detected when the parameter 24 exceeds or falls below the at least one predetermined threshold value 106a or valid range 106b.
[0020] It can be envisioned that the method 100 further includes triggering an event if a defect 26 in the housing 32 is detected. The event can be an indication to a user of the vehicle in which the control device 30 is included and / or a storage in an error memory.
[0021] In a first embodiment of the method 100, it can be assumed that the parameter 24 maps the time evolution of the first characteristic quantity 22 and is in particular the time derivative of the first characteristic quantity 22. This time derivative is also referred to as the gradient in the following.
[0022] It can be assumed that the relative air humidity is used as the first characteristic quantity 22.
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[0023] Time derivative drH of the relative air humidity 50 inside the housing 32 in / dt, drH in / dt=[(rH out -rH in ) / τ1]·(e -t / τ ) It can be expressed as follows.
[0024] In this case, with respect to the relative air humidity 52 outside the housing, rH out (t→∞)=rH in +τ·(drH in / dt) The allowed function range is assumed to be, for example, drH in / dt∈[-rHin / τ;(100%-rH in ) / τ] It can be expressed as:
[0025] The control device 30 essentially comprises pressure compensation valves, connections and / or seals, which allow the exchange of air humidity. The exchange of air humidity can be different depending on the exchange direction. This is shown by the following relationship: rH out >rH in or drH in / dt>0→τ is larger rH out <rH in or drH in / dt<0→τ is smaller This can be exemplarily expressed as follows: τ = ∑ ∑ a ∑ b ...
[0026] To measure the relative air humidity 50 inside the housing, sensors are typically used. These sensors have an operating range between, for example, 10% and 90% relative air humidity. Furthermore, a positive slope drH is used as a minimum measure. in A time constant τ = 3.5h is assumed for / dt, and a negative slope drH in If a time constant τ = 3h is assumed for / dt, the permissible function range can be calculated according to the above definition. rH in ∈[10%;90%] drH in / dt∈[-30% / h;26% / h] It can be expressed as follows: Gradient drH in / dt represents the parameter 24 in the first embodiment. in Parameter 24 is continuously determined and compared 106 to valid range 106b. Valid range 106b may map to the limits of the acceptable function range or may be applied to the corresponding control device using a test. If comparison 106 finds that parameter 24 is outside valid range 106b, there is a high probability that housing 32 of control device 30 has a defect 26.
[0027] In a first embodiment, as shown in FIG. 2, only the first sensor device 14 is required, which detects the first characteristic quantity 22, for example, as a signal characterizing the relative air humidity 50 inside the housing 32. This sensor device 14 is already present in many control devices, which can save costs. Because a gradient is used in this embodiment of the method 100, offset and drift do not affect the method 100. However, fluctuations in the relative air humidity 52 outside the housing 32 are not taken into account, which often requires a large difference between the relative air humidity 50 inside the housing 32 and the relative air humidity 52 outside the housing 32 to be able to reliably identify the defect 26.
[0028] In a second embodiment of the method 100, it is assumed that a second characteristic quantity 28 characterizing the air humidity 52 outside the housing 32 is detected 108, and a parameter 24 is determined 104 depending on the first characteristic quantity 22 and the second characteristic quantity 28, the parameter being a time constant τ for each individual housing characterizing the change in air humidity 50 inside the housing 32.
[0029] It can be assumed that relative air humidity is used as the first characteristic quantity 22 and the second characteristic quantity 28. In this example, the first characteristic quantity 22 is the relative air humidity 50 inside the housing 32 and the second characteristic quantity 28 is the relative air humidity 52 outside the housing 32 of the control device 30.
[0030] In a second embodiment, the following model is used for the relative air humidity 50 inside the housing 32:
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[0031] In this case, rH out,avg (t, t+dt) is the average relative air humidity 52 outside the housing 32 over the time range from t to t+dt. The time constant τ for each individual housing depends in this case on the size of the defect, e.g., leak. The time constant τ for each individual housing is defined as:
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[0032] The second characteristic quantity 28, which in this example is a signal characterizing the relative air humidity 52 outside the housing 32, is provided 108 by the second sensor device 16 as shown in FIG. 2. In the second embodiment, the time constant τ for each individual housing is continuously determined as parameter 24. The time constant τ for each individual housing is different for each different control device type or housing type and also changes if a defect 26 is present in the housing 32. The larger the defect 26, e.g., a leak, the smaller the time constant τ for each individual housing, because equilibrium occurs more quickly between the air humidity inside the housing 32 and the air humidity outside.
[0033] The second sensor device 16 is essentially exposed to multiple elements, and therefore offset drift correction and / or heating elements in the second sensor device 16 can be used to enable the second sensor device 16 to operate within an operating range of, for example, 10% to 90% relative air humidity.
[0034] In a second embodiment, the parameter 24, i.e., the time constant τ for each individual housing, is set to at least one predetermined threshold value 106a, e.g., τ threshold If the difference is less than 100%, a defect 26 in the housing 32 is detected. τ<τ threshold It can be expressed as follows.
[0035] It can be assumed that two predetermined thresholds 106a can be considered, depending on whether the relative air humidity 50 inside the housing 32 of the control device 30 is higher than the relative air humidity 52 outside the housing 32. Thus, depending on the first characteristic quantity 22 and the second characteristic quantity 28, it can be determined which of the at least one predetermined threshold 106a is used for the comparison 106 and for detecting the defect 26. As mentioned above, the time constant τ for the exchange of air humidity for each individual housing can be different depending on whether the relative air humidity 50 inside the housing 32 of the control device 30 increases or decreases. If the relative air humidity 52 outside the housing 32 is higher than the relative air humidity 50 inside the housing 32, the relative air humidity 50 inside the housing 32 increases. If the relative air humidity 52 outside the housing 32 is lower than the relative air humidity 50 inside the housing 32, the relative air humidity 50 inside the housing 32 decreases.
[0036] 2 shows in a schematic diagram an apparatus 10 for detecting defects 26, in particular leaks, in the housing 32 of a control device 30. The apparatus 10 comprises a first sensor arrangement 14 for detecting air humidity 50 inside the housing 32 of the control device 30 and an optional second sensor arrangement 16 for detecting air humidity 52 outside the housing 32, for example if the second embodiment of the method 100 is used. The apparatus 10 further comprises a calculation unit 12 configured to implement the method 100. To make the method 100 more robust, the parameter 24 is calculated as the time derivative drH in / dt and the identified time constant τ for each individual housing, which the method 100 takes into account in the comparison 106. It is also conceivable that the calculation unit 12 is configured to perform the first and second embodiments of the method 100 in parallel. For example, it is also conceivable that the calculation unit 12 is configured to perform the first and second embodiments of the method 100 redundantly in case the second sensor device 16 fails.
[0037] FIG. 2 further illustrates a defect 26, shown as a leak, in the housing 32 of the control device 30, which causes equilibrium between the air humidity 50 inside the housing 32 and the air humidity 52 outside the housing 32 to be achieved more quickly compared to an undamaged housing or a relatively small defect 26.
[0038] The calculation unit 12 may be constituted by the control device 30 or a further control device, the control device 30 being in particular constituted as a control device for a steer-by-wire steering system.
[0039] The threshold value 106a and / or the valid range 106b may be determined, for example, by testing a series of the same type of control device 30. If the series includes multiple control devices 30, it is advantageous for multiple housings 32 to have differently configured defects 26. It is advantageous for at least one control device 30 to be free of a defective housing 32 so that an appropriate reference value can be determined.
[0040] One control device 30 from the test series can be placed in a test chamber, which is used to achieve positive or negative jumps in air humidity to a settable target value. As the test series is performed, the relative air humidity 50 inside the housing 32 and the relative air humidity 52 outside the housing 32 are continuously detected and recorded. This can be done, for example, using the first sensor device 14 and the second sensor device 16, or it can be done using sensors in the test chamber. For each control device in the test series, the model described above and the recorded relative air humidity, referred to for brevity as measurement data, are used to determine the time constant τ for each individual housing. i where the subscript i characterizes one particular controller in the test series. In this case, since the jumps are not ideal, the test chamber also has a time constant τ chamber It should be considered that the time constant τ chamber can be compensated from the recorded measurement data.
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[0041] 3 shows the progression of air humidity rH over time t for an exemplary test series. The test series includes a first control device 30a with an undamaged housing 32 that does not have any defects 26, a second control device 30b with a housing 32 that has through-holes with a diameter of 1 mm, and a third control device 30c with a housing 32 that has through-holes with a diameter of 2 mm. These through-holes represent defects 26 in the form of leaks. However, the control devices 30a-30c are identical except for the through-holes and are control devices for steer-by-wire steering systems.
[0042] 3 further shows the progression of the relative air humidity 52 outside the housing 32, as generated by the test chamber. Using the test chamber, in this example, a positive jump in the relative air humidity 52 outside the housing 32 of the control device 30 is mapped. The dashed line shows the progression of the relative air humidity 50a inside the housing 32 of the control device 30a. The dotted line shows the progression of the relative air humidity 50b inside the housing 32 of the control device 30b. The dashed-dotted line shows the progression of the relative air humidity 50c inside the housing 32 of the control device 30c. For all the control devices 30a, 30b, and 30c in the test series, the corresponding time constants τ for each individual housing were calculated from the recorded measurement data. a ,τ b and τ c Our corresponding tests allow us to determine, for example, τ for a fault-free control device 30a. a A time constant of τ = 6.9h was obtained for each individual housing, and τ b A time constant of τ = 5.8h was obtained for each individual housing, and τ c Based on these findings from a series of tests, the threshold value 106a for parameter 24 was set to τ thresholdA time constant of ≈6.9 h can be selected for each individual housing. The error tolerance of the threshold 106a can be determined by a series of further tests and taken into account accordingly.
[0043] The parameter 24 is the gradient drH of the relative air humidity 50 inside the housing 32. in If the time derivative is in the form of / dt, then an upper limit for the valid range 106b can also be identified starting from an exemplary series of tests that map a positive jump or increase in relative air humidity 52 outside the housing 32. The upper limit can be determined according to the above formula: (100%-10%) / 6.9h=13.04% / h is decided.
[0044] 4a shows a test setup 60 for testing that can be used to determine the threshold 106a and / or the upper and lower limits of the valid range 106b. The test setup 60 includes a space 62 in which the relative air humidity is controlled, e.g., with a target value of 30% relative air humidity. The space 62 includes a chamber 64 that has a higher air humidity than the air humidity of the space 62, e.g., 70% relative air humidity. Using the method 600, it is possible to nearly ideally map the positive and negative jumps in the relative air humidity 52 outside the housing 32.
[0045] 4b shows a flowchart of a method 600 for determining a threshold 106a and / or a valid range 106b for the method 100 for determining a defect 26 in the housing 32 of the control device 30. In step 602, a space 62 is used to provide a settable relative air humidity 52a inside the space 62. In step 604, a chamber 64 is used to provide a settable relative air humidity 52b inside the chamber 64, the settable relative air humidity 52b inside the chamber 64 being higher than the settable relative air humidity 52a inside the space 62.
[0046] In step 606, at least one control device 30 of the test series is placed in the space 62. The residence time of the placed control device 30 in the space 62 may be selected so that the value of the relative air humidity 50 inside the housing 32 of the control device 30 is at least 95% of the value of the relative air humidity 52a inside the space 62. The placed control device 30 may have a residence time in the space 62 that is at least approximately three times the time constant τ for each housing of a fault-free control device 30, in particular to ensure sufficient equilibrium between the relative air humidity 52a of the space 62 outside the housing 32 and the relative air humidity 50 inside the housing 32. This residence time may be, for example, approximately 20 to 24 hours.
[0047] Step 606 is followed by step 608, in which the control device 30 is placed in the chamber 64. The residence time of the control device 30 within the chamber 64 may be selected so that the value of the relative air humidity 50 inside the housing 32 of the control device 30 is at least 78% of the value of the relative air humidity 52b inside the chamber 64. The residence time of the control device 30 within the chamber 64 may correspond to at least approximately 1.5 times the time constant τ for each individual housing of a fault-free control device 30. This residence time may be, for example, 8 to 10 hours. This maps a positive jump in the relative air humidity 52 outside the housing 32. In this case, the relative air humidity 50 inside the housing 32 of the control device 30 increases.
[0048] Step 608 is followed by step 610, in which the control device 30 is placed from the chamber 64 into the space 62. The residence time of the control device 30 within the space 62 may be selected so that the value of the relative air humidity 50 inside the housing 32 of the control device 30 is at least 78% of the value of the relative air humidity 52a inside the space 62. The residence time of the control device 30 within the space 62 may correspond to at least approximately 1.5 times the time constant τ for each individual housing of a fault-free control device 30. This residence time may be, for example, 8 to 10 hours. This maps out a negative jump in the relative air humidity 52 outside the housing 32, which in turn reduces the relative air humidity 50 inside the housing 32 of the control device 30.
[0049] The method 600 further comprises detecting 612, particularly continuously during steps 602 to 610, the relative air humidity 52a and 52b outside the housing 32 and the relative air humidity 50 inside the housing 32. This may be done, for example, using the first sensor device 14 and the second sensor device 16, or using sensors in the chamber 62 or space 64.
[0050] In step 612, starting from the detected measurement data in the form of the relative air humidity 52a and 52b outside the housing 32 and the relative air humidity 50 inside the housing 32, the time constant τ for the rise of the relative air humidity 50 inside the housing 32 is calculated for each control device 30 in the series of tests, for example using the model described above. i,1 and the time constant τ for each individual housing for the relative air humidity 50 inside the housing 32 to decrease. i,2 For the purpose of mapping the error tolerance of the control device, statistical methods, such as Gaussian normal distribution and mean value determination, taking into account the standard deviation in the form of μ±3σ, may be useful.
[0051] The upper and lower limits of the valid range 106b can be determined, for example, by considering the above-described model:
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[0052] The at least one threshold value 106a may be determined, for example, from measurement data of an undamaged or damaged control device 30, or from a test series of a plurality of undamaged control devices 30, or from a test series of a mixture of undamaged and damaged control devices 30. In this case, the time constant τ for each individual housing determined in step 614 may be determined. i,1 ,τ i,2 may be used as a basis for setting one or more thresholds 106a, with or without consideration of tolerances.
Claims
1. A method (100) for detecting defects (26), in particular leaks, in a housing (32) of a control device (30), comprising: - detecting (102) a first characteristic quantity (22) characterizing the air humidity (50) inside the housing (32); - determining (104) a parameter (24) characterizing the variations in the air humidity (50) inside the housing (32) in dependence on the first characteristic quantity (22); comparing (106) said parameter (24) with at least one predetermined threshold (106a) or a predetermined valid range (106b), wherein a defect (26) in said housing (32) is detected (106) when said parameter (24) exceeds or falls below said at least one threshold (106a) or said valid range (106b); A method (100) comprising:
2. the parameter (24) maps the change over time of the first characteristic value (22), and in particular is the time derivative of the first characteristic value (22); The method (100) of claim 1.
3. Relative air humidity is used as the first characteristic value (22), The method (100) of claim 2.
4. - detecting (108) a second characteristic value (28) characterizing the air humidity (52) outside the housing (32); - determining (104) the parameter (24) depending on the first characteristic value (22) and the second characteristic value (28), the parameter being a time constant for each individual housing characterizing the change in the first characteristic value (22); The method (100) of claim 1, comprising:
5. Relative air humidity is used as the first characteristic value (22) and the second characteristic value (28). The method (100) of claim 4.
6. a defect (26) in the housing (32) is detected when the parameter (24) falls below the at least one predetermined threshold (106a); The method (100) of claim 5.
7. A device (10) for detecting defects (26), in particular leaks, in a housing (32) of a control device (30), comprising: a first sensor device (14) configured to detect (102) a first characteristic quantity (22) characterizing the air humidity (50), in particular the relative air humidity (50), inside the housing (32) of the control device (30); an optional second sensor device (16) configured to detect (108) a second characteristic quantity (28) characterizing the air humidity (52), in particular the relative air humidity (52), outside the housing (32) of the control device (30); A computing unit (12) configured to perform the method (100) according to any one of claims 1 to 6; An apparatus (10) comprising:
8. a control device (30) having a housing (32); A device (10) according to claim 7, Vehicles including.
9. A method (600) for determining at least one threshold (106a) and / or validity range (106b) for the method (100) of any one of claims 1 to 6, comprising: Providing (602) a relative air humidity (52a) inside the space (62); Providing (604) a relative air humidity (52b) inside a chamber (64), the chamber (64) being located in the space (62), the relative air humidity (52b) inside the chamber (64) being higher than the relative air humidity (52a) inside the space (62); placing (606) a control device (30) of a series of tests inside the space (62), the residence time of the control device (30) inside the space (62) being selected in particular so that the value of the relative air humidity (50) inside the housing (32) of the control device (30) is at least 95% of the value of the relative air humidity (52a) inside the space (62); - placing (608) the control device (30) from the space (62) into the chamber (64), the residence time of the control device (30) in the chamber (64) being selected in particular so that the value of the relative air humidity (50) inside the housing (32) of the control device (30) is at least 78% of the value of the relative air humidity (52b) inside the chamber (64); - placing (610) the control device (30) from the chamber (64) into the space (62), the residence time of the control device (30) in the space (62) being selected in particular so that the value of the relative air humidity (50) inside the housing (32) of the control device (30) is at least 78% of the value of the relative air humidity (52a) inside the space (62); Detecting (612) the relative air humidity (52a) inside the space (62), the relative air humidity (52b) inside the chamber (64), and the relative air humidity (50) inside the housing (32) of the control device (30); A time constant (τ) for at least one individual one of the housings (32) of the control device (30) ｉ，１ , τ ｉ，２ determining (614) the relative air humidity (52a) within the space (62), the relative air humidity (52b) within the chamber (64), and the relative air humidity (50) within the housing (32) of the control device (30); A method (600) comprising:
10. The at least one threshold value (106a) and / or the effective range (106b) for the method (100) are determined based on a time constant (τ) for each of the at least one individual housings (32) of the control device (30). ｉ，１ , τ ｉ，２ ) and setting it as dependent on 10. The method (600) of claim 9.