Field devices with process-specific condition monitoring capabilities

Abstract

The invention relates to a device (1) for determining and / or monitoring at least one process variable (P) of a medium (M), the device comprising: a sensor unit (3) for detecting the value of the process variable (P); a time detection unit (5) for detecting at least one operating duration (t); and a calculation unit (6) designed to generate at least one statement about the state of at least one component of the device (1) using at least the operating duration (t) detected by the time detection unit (5) and using at least one influencing variable (E) influencing the operating duration (t). The invention also relates to a method for operating the device (1) according to the invention.

Description

Technical Field

[0001] The invention relates to a device for determining and / or monitoring at least one process variable of a medium and to a method for operating the device according to the invention. Background Art

[0002] Such field devices are used to monitor and / or determine at least one (e.g. chemical or physical) process variable of a medium. In the context of the present invention, field devices are in principle all measuring devices which are used in the vicinity of the process and which transmit or process process-related information, thus also including remote I / Os, radio adapters and electronic components which are usually arranged at field level. The Endress+Hauser Group of Companies produces and sells a large number of such field devices.

[0003] For example, the field device can be a level measuring device, a flow measuring device, a pressure and temperature measuring device, a pH and / or pH redox potential measuring device, or even a conductivity measuring device, which records the corresponding process variables, level, flow, pressure, temperature, pH value, redox potential and conductivity. The basic measurement principles are well known in the prior art and are not explained separately here. In the case of flow measuring devices, they are in particular Coriolis, ultrasonic, vortex, thermal and / or magnetic inductive flow measuring devices. Level measuring devices are in particular microwave level measuring devices, ultrasonic level measuring devices, time domain reflectometer level measuring devices (TDR), radiometric level measuring devices, capacitive level measuring devices, conductive level measuring devices and / or temperature sensitive level measuring devices. In contrast, in the case of pressure measuring devices, there are absolute pressure, relative pressure and differential pressure devices, while temperature measuring devices can determine the temperature using, for example, thermocouples or temperature-dependent resistors.

[0004] The field device comprises at least one sensor unit which is at least partially and at least sometimes in contact with the process and an electronics unit, for example, for signal recording, evaluation and / or feeding. Typically, at least the electronics unit of the field device is arranged in a housing which has an opening for introducing at least one connecting cable into the field device.

[0005] In order to obtain information about the total operating time of the field device, the field device is usually equipped with an operating time counter. In this way, for example, information can be obtained with reference to the replacement of the field device that may be needed in the process.

[0006] During ongoing operation in the process, field devices are exposed to the most diverse environmental and / or process conditions. In this context, specific ambient conditions can have a significant impact on the service life of a specific measuring device or individual components of a measuring device. Predictions made based on operating hours counters about possible failures of a device can accordingly be subject to large errors. Summary of the invention

[0007] It is therefore an object of the present invention to provide an opportunity for obtaining a more precise understanding of the status of a field device in ongoing operation.

[0008] This object is achieved by a device for determining and / or monitoring at least one process variable of a medium and by a method for operating the device.

[0009] With regard to the device, the object is achieved by a device for determining and / or monitoring at least one process variable of a medium, the device comprising

[0010] - a sensor unit for recording the value of a process variable,

[0011] a time recording unit for recording at least one operation duration,

[0012] as well as

[0013] A calculation unit which is implemented to make at least one statement with reference to a state of at least one component of the device at least based on the operating duration recorded by the time recording unit and based on at least one influencing variable influencing the operating duration.

[0014] For example, the time recording unit can be an operating time counter. In the case of conventional operating time counters, usually only the total operating time of the field device is accumulated. The time information gained by means of the operating time counter does not contain data about the specific process state using the specific field device. On the contrary, according to the present invention, in connection with condition monitoring, at least one influencing variable is taken into account in order to determine information about the state of at least one component of the reference device. Such an influencing variable may have a significant influence on the state of the field device. Therefore, the condition monitoring is not only based on the operating duration determined by means of the time recording unit, but also takes into account the specific application of the device. In this way, significantly more accurate and more reliable information about the state can be obtained.

[0015] Advantageously, the influencing variables are process parameters, process variables or environmental parameters, in particular temperature (in particular the temperature of a component of the process or the device), pressure (in particular the pressure in a container in which the medium is located), moisture content (in particular the humidity of the surrounding environment), vibrations occurring in the area of ​​the device, the flow rate of the medium, the pH value of the medium or the conductivity of the medium.

[0016] Specific process parameters or process properties of the medium and / or environmental parameters of the specific process significantly influence the state of the field devices used, in particular the achievable service life. For example, operating a field device at excessively high temperatures, pressures or moisture contents can lead to defects or even to complete failure of the device or at least individual components of the device.

[0017] In an embodiment, the device comprises a measuring unit for recording the value of the influencing variable, in particular, wherein the measuring unit is a device for determining temperature, pressure, moisture content, a device for detecting vibrations, or a device for determining flow, pH value or conductivity. In this case, on the one hand, one option is that the device has a separate measuring unit for recording the value of the influencing variable. However, depending on the selected sensor unit, this sensor unit can also be used to record the value of the influencing variable.

[0018] Furthermore, other exemplary embodiments include recording the value of the influencing variable independently of the arrangement or separately, for example by means of another field device or by means of another measuring unit.

[0019] A preferred embodiment proposes that the device includes at least a first module and a second module, wherein the computing unit is implemented to make a first statement with reference to the state of the first module of the device and a second statement with reference to the state of the second module of the device at least based on the operation duration recorded by the time recording unit and based on at least one influencing variable affecting the operation duration, or wherein there are two computing units, wherein the first computing unit is implemented to make a first statement with reference to the state of the first module, and wherein the second computing unit is implemented to make a second statement with reference to the state of the second module.

[0020] In this way, it can be taken into account that certain influencing variables have a greater influence on individual components than other influencing variables, or that certain influencing variables only influence individual components.

[0021] In this case, advantageously, the first module is a sensor unit of the device and / or the second module is an electronic unit of the device. Usually, the electronics are arranged outside the process, while in many cases the sensor unit is at least partially and / or sometimes in contact with the medium. In the case of a direct connection of the electronic unit to the sensor unit, and in the case of a separate arrangement of the electronic unit and the sensor unit, there are two field devices of so-called compact structure. Therefore, different influencing variables may affect different modules to different extents. For example, the electronic unit and the sensor unit of the field device are often implemented with different maximum operating temperatures.

[0022] In an additional preferred embodiment, the device comprises a display unit for displaying (in particular visually) at least one statement referring to the state of a component of the device. In this case, the most diverse display units can be used, for example, a display unit for displaying a graphical image, or a display unit comprising a visual display element, for example in the form of one or more (in particular colored) LEDs.

[0023] Furthermore, the object of the invention is achieved by a method for operating an apparatus according to the invention, wherein the value of a process variable is recorded, the operating duration is recorded, and wherein at least one statement is made about the state of at least one component of the reference device at least based on the recorded operating duration and on at least one influencing variable influencing the operating duration.

[0024] In a preferred embodiment of the method, the statement referring to the state of at least one component of the device is a process-specific operating duration of at least one component of the device. In addition to the pure operating duration, the process-specific operating duration also takes into account the special influence of influencing variables. For certain ranges of specific influencing variables, it may be advantageous to limit the operating duration in order to avoid premature damage to components of the device or to the entire device.

[0025] In an additional preferred embodiment, the statement referring to the state of at least one component of the device is a probability of occurrence of a defect or malfunction of at least one component of the device.

[0026] In a further preferred embodiment of the method, the statement about the state of at least one component of the reference device is a load of at least one component of the device.

[0027] In the context of the present invention, one or more statements about the state of the device can be made. For this purpose, the same or even different influencing variables can be considered. In addition, different statements can be directed to different modules of the device.

[0028] Furthermore, in the context of the method of the invention, it is advantageous if the statements referring to the state of the additional device are made by the additional device for monitoring the medium. Thus, state monitoring of other field devices arranged in the process and exposed to the same process and / or environmental states can also take place.

[0029] In a preferred embodiment, at least a first value range and a second value range are predetermined for the influencing variable. Then, in particular, a first value of the operating duration of the device and a second value of the operating duration of the device can be determined, the first value corresponding to the value of the influencing variable within the first value range and the second value corresponding to the value of the influencing variable within the second value range. According to the invention, at least two (preferably three) value ranges are predetermined. In addition, for different modules of the device and / or for different influencing variables or combinations of at least two influencing variables, different numbers of value ranges can be predetermined. In addition, for one or more than one influencing variable, the individual value ranges can have equally large or unequally large intervals.

[0030] In this case, a statement referring to at least one component of the device is advantageously made for each of the at least two value ranges.

[0031] However, alternatively, it is also possible and advantageous to prescribe a weighting factor for at least one value range.Regarding the at least one weighting factor, it is advantageous when a statement about at least one component of the device is made based on at least two value ranges of the influencing variable and based on the at least one weighting factor.

[0032] It should be noted that the embodiments described for the apparatus of the present invention may also be applied mutatis mutandis to the method of the present invention, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Now refer to Figures 1 to 4 The invention and its advantageous embodiments are explained in more detail.

[0034] The attached picture is as follows:

[0035] Figure 1 is a first embodiment of the device according to the invention having a sensor unit, a time recording unit, a calculation unit and an additional measuring unit,

[0036] Figure 2 is a second embodiment of the device according to the invention having two computing units and a display unit,

[0037] Figure 3 illustrates the provisions that affect different value ranges of variables, and

[0038] Figure 4 It is a device according to the invention in the form of a thermometer having two modules.

[0039] In the figures, identical elements are provided with the same reference symbols. DETAILED DESCRIPTION

[0040] Figure 1 A field device 1 is shown for determining and / or monitoring at least one process variable P of a medium M, wherein the medium M is located in a container 2. Of course, however, in the context of the present invention the medium M may also be located in some other type of container, such as a pipeline, or even without any container.

[0041] The device 1 comprises a sensor unit 3 for recording the value of a specific process variable P and an electronics unit 4. In the present example it is a modular field device 1 of compact construction, wherein a first module is provided by the sensor unit 3 and a second module is provided by the electronics unit 4. However, other types of field devices also fall within the scope of the invention.

[0042] A time recording unit 5 for recording at least one operating duration t of the device 1 is arranged in the electronic unit 4. Furthermore, the electronic unit 4 comprises a computing unit 6. It should be noted here that the time recording unit 5 and the computing unit 6 do not have to be arranged in the electronic unit 4. They can also be arranged outside the electronic unit 4.

[0043] The device 1 additionally comprises a measuring unit 7 for recording the value of the influencing variable E. In the present example, the measuring unit 3 is arranged such that it records a process parameter p of the medium M. In other embodiments, the measuring unit can also be implemented for determining an environmental parameter u, thus for determining a parameter outside the medium M and / or the container 2. For example, the process parameter p is the temperature or the pressure of the medium. However, as mentioned above, other process parameters are also conceivable.

[0044] According to the invention, the calculation unit 6 is implemented to make at least one statement with reference to the state of the device 1 based on the operating duration t recorded by the time recording unit 5 and at least on the influencing variable E which influences the operating duration t. For example, the statement can be a process-specific operating duration t of the device 1. p , the probability of a defect or failure of device 1 or the load of the device.

[0045] Figure 2 A second possible embodiment of the device 1 of the invention is shown. Figure 1In contrast, the device 1 comprises a first calculation unit 6 and a second calculation unit 8. The first calculation unit 6 is implemented to make a first statement with reference to the state of the sensor unit 3 and a second statement with reference to the state of the electronic unit 4 of the device 1 at least based on the operating duration t recorded by the time recording unit 5, and the second calculation unit 8 is implemented to make a second statement with reference to the state of the electronic unit 4 of the device 1 based on at least one influencing variable E influencing the operating duration t. To determine the first statement and the second statement, the first calculation unit 6 and the second calculation unit 8 can take into account the same influencing variable E or different influencing variables E1, E2. In other embodiments, multiple statements can then be determined with the aid of the same calculation unit 6, in particular two statements about the electronic unit 4 and the sensor unit 3. Moreover, each module 3, 4 can have its own time recording unit 5, 9 [the second time recording unit is drawn in dashed lines].

[0046] also, Figure 2 The device 1 comprises a display unit 10. The display unit is used to display at least one statement (in particular visually) referring to the state of the device 1. For the embodiment shown here, the display unit 10 is also associated with the electronic unit 4. In other embodiments, the display unit can be a separate unit.

[0047] It should be noted here that in other embodiments, Figure 1 and Figure 2 The individual components of the device can be combined with one another in other ways. Therefore, the embodiments shown are to be regarded as individual possible examples only.

[0048] Figure 3 Shown are possible examples for specifying individual value ranges for the device 1 according to the invention or the method according to the invention. Figure 3 a and Figure 3 b, two w1, w2 or three equal value ranges w1 to w3 are predetermined for the influencing variable E. In contrast, Figure 3 In the case of the influencing variable E, four different large value ranges w1 to w4 are predetermined. In this case, the value range w is preferably predetermined or selected accordingly depending on the influence E on the operating duration t of the device 1. One option is then, for example, to make a statement in each case with reference to the device 1 for each value range v, or to specify a weighting factor for at least one of the value ranges v. Then, in turn, a statement about the device can be made based on at least two value ranges w1, w2 of the influencing variable E and based on at least one weighting factor.

[0049] Another option for additional embodiments is obtained by prescribing different value ranges w for different modules 3 , 4 of the device 1 or different value ranges w for different influencing variables E. In this case, the different statements can be determined in a single calculation unit 6 or in a plurality of processing units 6 , 8 .

[0050] It should be noted here that Figures 1 to 3 The exemplary embodiment shown, instead of making statements about the entire device 1 , can also make different statements about different modules (eg the electronics unit 4 or the sensor unit 3 ).

[0051] Figure 4 Another example of an embodiment of the invention is shown with a device in the form of a thermometer 1. The thermometer 1 comprises a sensor unit 3 in the form of a resistance element, which is connected to an electronics unit 4 via two connecting lines 11a, 11b. In other embodiments, for example, a sensor element 3 with a thermocouple can also be used. In principle, all sensor units 3 known from the prior art and used in conjunction with a thermometer 1 can be used.

[0052] for Figure 4 In the example of the embodiment shown, the temperature T of the medium is both the process variable P and the influencing variable E. Accordingly, for Figure 4 The device 1 does not require a separate measuring unit 7.

[0053] Typically in the case of a thermometer 1 , different maximum temperatures are permitted for the sensor unit 3 and the electronics unit 4 . Operation of a specific module (i.e. the sensor unit 3 or the electronics unit 4 ) at relatively high temperatures T (i.e. temperatures close to the maximum permitted operating temperature) leads to an increased probability of the occurrence of defects in the specific module 3 , 4 or to the need to replace the specific module at an earlier point in time than would be the case if the thermometer 1 were operated only at a lower temperature T. The temperature T of the medium therefore represents an influencing variable E which influences the operating duration t of the device 1 . In the context of the present invention, statements can be made in each case for the entire device 1 or for different modules 3 , 4 respectively and / or for different value ranges. Alternatively, weighting factors can be determined for different modules 3 , 4 and / or value ranges. Then, for example, based on the different statements or based on individual statements and corresponding weighting factors, a process-specific operating duration t can be determined for one of the modules 3 , 4 or for the device 1 p .

[0054] Advantageously, the invention enables reliable and precise condition monitoring based on an operating duration t of the device and on at least one influencing variable which influences the operating duration t.

[0055] Reference Mark

[0056] 1 Device

[0057] 2 Container

[0058] 3 Sensor unit

[0059] 4 Electronics unit

[0060] 5 Time Recording Unit

[0061] 6 Computational Unit

[0062] 7 Measurement unit

[0063] 8 Second computing unit

[0064] 9 Second time recording unit

[0065] 10 Display unit

[0066] 11, 11a, 11b connection cable

[0067] M Medium

[0068] P Process variable

[0069] E Influencing variables

[0070] p process parameter

[0071] Environmental parameters

[0072] T Temperature

[0073] w value range

[0074] t Operation duration

[0075] t p Process specific operation duration

Claims

1. A device (1) for determining and / or monitoring at least one process variable (P) of a medium (M), comprising: a sensor unit (3) as a first module, wherein the sensor unit is implemented to record the value of the process variable (P) and is at least partially and / or sometimes in contact with the medium (M) during the determination and / or monitoring of the process variable (P), - an electronics unit (4) as a second module, wherein the electronics unit (4) is implemented for signal recording, evaluation and / or feeding, a time recording unit (5) for recording at least one operation duration (t), the time recording unit being implemented as an operation time counter, as well as a first calculation unit (6) which is implemented to make at least one statement with reference to the state of at least one component of the device (1) based at least on the operating duration (t) recorded by the time recording unit (5) and on at least one influencing variable (E) influencing the state of the device including the achievable service life of the device, Wherein, the influencing variable (E) is a process parameter (p), a process variable (P) or an environmental parameter (e), Wherein, the process parameter (p), the process variable (P) or the environmental parameter (e) is one of the following: - the temperature (T) of a process or a component of the device (1), -pressure, - moisture content, - vibrations occurring in the region of the device (1), - the flow rate of the medium (M), - the pH value of the medium (M); and - the electrical conductivity of the medium (M), wherein the first calculation unit (6) is implemented to make a first statement with reference to at least the state of the sensor unit (3) and a second statement with reference to the state of the electronic unit (4) of the device (1), at least based on the operating duration (t) recorded by the time recording unit (5) and based on at least one influencing variable (E), or There are two calculation units, wherein the first calculation unit (6) is implemented to make the first statement with reference to the state of the sensor unit (3), and wherein the second calculation unit (8) is implemented to make the second statement with reference to the state of the electronic unit (4).

2. The device (1) according to claim 1, in, The pressure is the pressure in the container (2) where the medium (M) is located.

3. The device (1) according to claim 1, in, The moisture content is the humidity of the surrounding environment.

4. The device (1) according to any one of claims 1 to 3, It also comprises at least one measuring unit (7) for recording the value of the influencing variable (E), wherein: The measuring unit (7) is a device for determining temperature (T), pressure, moisture content, a device for detecting vibrations or a device for determining flow, pH value or conductivity.

5. The device (1) according to any one of claims 1 to 3, Also included is a display unit (10) for displaying the at least one statement with reference to the status of the components of the device (1).

6. The device (1) according to any one of claims 1 to 3, Also included is a display unit (10) for visually displaying the at least one statement with reference to the status of a component of the device (1).

7. A method for operating a device (1) according to any one of claims 1 to 6, wherein: - recording the value of said process variable (P), - recording the operation duration (t) using said operation time counter, as well as - at least based on the recorded operating duration (t) and based on the at least one influencing variable (E), at least one statement is made with reference to the state of at least one component of the device (1), wherein a first statement is made with reference to the state of the sensor unit (3) and a second statement is made with reference to the state of the electronic unit (4).

8. The method according to claim 7, in, The statement referring to the state of at least one component of the device (1) is a process-specific operating duration (t p ).

9. The method according to claim 7 or 8, in, The statement referring to the state of at least one component of the device (1) is the probability of occurrence of a defect or malfunction of at least one component of the device (1).

10. The method according to claim 7 or 8, in, The statement referring to the state of at least one component of the device (1) is a load of at least one component of the device (1).

11. The method according to claim 7 or 8, in, The statement is made with reference to the status of additional means for monitoring said medium (M).

12. The method according to claim 7 or 8, in, At least a first value range and a second value range are predetermined for the influencing variable (E).

13. The method according to claim 12, in, For each of the at least first range of values ​​and the second range of values, a statement is made with reference to at least one component of the device (1).

14. The method according to claim 12, in, A weighting factor is specified for at least one value range.

15. The method according to claim 14, in, Based on the at least first value range and the second value range for the influencing variable (E) and based on at least one weighting factor, the statement is made about at least one component of the device (1).

Images