Display device for showing process values

Abstract

The invention relates to a display device (1) for displaying process values, comprising: a display area (2) with several display segments (3), wherein the display of a process value is effected by activating at least one display segment (3), means for determining the fluctuation dynamics of the process values ​​in a time unit t, and means for monitoring the fluctuation dynamics with respect to a predetermined threshold value. When the threshold value is exceeded, the display of the process values ​​between their min-max limits in the time unit t is effected by activation, i.e., optical highlighting of a defined area (4) of several display segments (3).

Description

[0001] The present invention relates to a display device for showing process values.

[0002] Display devices of the aforementioned type are used in a wide variety of applications, particularly in automation and process measurement technology, for example, for pressure and temperature monitoring in tanks and pipelines. In the case of an electronic display device, it is supplied with power via a connection device, typically a plug connector. Simultaneously, measured values, e.g., as a 4-20 mA signal, can be transmitted to an external control unit, such as a PLC. Such a display device is shown, for example, in German patent DE 10 2009 017 783 B4 of the applicant.

[0003] Display devices that show process values ​​using pointers are well known. These pointers can be physical or electronic, displayed on a screen. Conventional mechanical and electronic displays show the process values ​​directly, which can lead to difficult-to-read displays when there are large fluctuations. Approaches such as filtering or averaging stabilize the display, but often lack dynamic adjustment to the intensity of fluctuations. Existing solutions do not provide sufficient visual support for highly dynamic processes, which can lead to increased misinterpretation of the process value by the user.

[0004] Document US 6,412,187 B1 discloses a measuring instrument with a combined digital and analog display. The analog display, in the form of a bar graph, can show a measured value, a peak value, and user-defined tolerance limits. If a peak value exceeds the displayable analog range, the display is rescaled by an offset adjustment so that the value is again shown within the display range, preferably at its center.

[0005] Document DE 199 40 434 A1 discloses a display device in which several signal parameters are simultaneously displayed graphically in a single display field for improved clarity. In addition to the current signal value, these can include, for example, statistical values ​​such as a minimum, maximum, and average value, as well as predefined upper and lower limits.

[0006] Document DE 10 2012 019 617 A1 discloses a pressure transmitter measuring system in which a process pressure is detected by a sensor and transmitted as an electronic signal to a separate display unit. The pointer of the display unit is electronically controlled. To improve readability in the event of rapid or vibrating changes in the measured value, the pointer movement can be dampened or delayed.

[0007] Document DE 697 21 698 T2 discloses a sensor device in which a measured characteristic value and an associated, adjustable threshold are displayed simultaneously and in direct visual correlation to each other as a bar chart. This allows the user to grasp the relationship between the measured value and the threshold and to adjust the threshold precisely.

[0008] Document DE 10 2018 126 790 A1 discloses a variable area flowmeter whose display unit, in addition to a mechanical pointer, has a bistable display, such as electronic paper. This makes it possible to change the displayed value scale electronically and thus to flexibly adapt the measuring device to different process parameters, such as different media or pressures, while maintaining the purely mechanical measuring process.

[0009] Document JP 2018-136165 A discloses a display device that visually represents the degree of deviation of a measured value from a mean or target value for a list of measurements. The area between an indicator for the mean value and an indicator for the current measured value is highlighted in color. The color changes as the measured value deviates from the mean value, thus making the degree of deviation and compliance with tolerance limits immediately apparent.

[0010] The object of the invention is to propose a display device in which readability is improved in the case of high fluctuation dynamics of the process values.

[0011] The problem is solved by a display device having the features of claim 1. Advantageous embodiments of the invention are specified in the dependent claims.

[0012] The display device according to the invention comprises a display area consisting of several display segments, which represents a process value when at least one display segment is activated. In the case of strong fluctuations in the process value, the range within which the process value fluctuates is displayed as a span between its minimum and maximum limits during a time unit t. This function is activated when the fluctuation dynamics of the process value exceed a predetermined threshold. According to the invention, this threshold is determined as a function of the rate of change of the at least one display segment used to represent the process value.

[0013] Preferably, hysteresis ensures that the switch-on and switch-off times of the clamping process are stabilized to guarantee a flicker-free and consistent display.

[0014] Preferably, a moving average of the process values ​​during the time unit t is displayed as a single display segment within the defined area, in contrast to the defined area.

[0015] The invention offers several advantages. First, readability is significantly improved by displaying the process value, as the user can immediately see a high degree of fluctuation in the process values ​​and simultaneously read the extent of this fluctuation. Furthermore, the moving average display provides the average value, which is particularly advantageous in cases of very high fluctuations. Second, the visual strain on the human eye is reduced, as it no longer has to follow every rapid change in the display segments. Third, hysteresis ensures a stable display by regulating the activation and deactivation times of the display. Fourth, the display threshold is dynamically calculated as a velocity, allowing for flexible adaptation to different process conditions.Fifthly, the invention enables the display of rapid process value changes that cannot be detected using conventional display methods. Finally, the invention enables the detection of high-frequency process value fluctuations.

[0016] An optional configurable damping can modify the process value to reduce the displayed area. This further contributes to the stability and readability of the display.

[0017] Preferably, the display device is designed as a pressure gauge.

[0018] The invention will now be explained in more detail using exemplary embodiments and with reference to the drawings.

[0019] They show schematically: Fig. 1. An exemplary progression of a process value; Fig. 2a a display device according to the invention in a first embodiment; Fig. 2b a display device according to the invention in a second embodiment; Fig. 2c a display device according to the invention in a third embodiment; Fig. 2d a display device according to the invention in a fourth embodiment; Fig. 3 a display device according to the invention as a manometer.

[0020] In the following description of preferred embodiments, identical reference numerals denote identical or comparable components.

[0021] In Fig. Figure 1 shows an exemplary curve of a process value, characterized in this case by a particularly high dynamic range in the form of high-frequency fluctuations, also with regard to maximum and minimum values. Such a pressure signal curve can be observed, for example, when a valve in a pipeline is opened or closed. If this signal curve were displayed by a pressure gauge whose pointer directly follows the pressure curve, a reliable reading of the pressure value would hardly be possible.

[0022] The Fig. Figures 2a-d show different embodiments of a display device 1 according to the invention, wherein Fig. 2a and Fig. 2b each show a rectangular bargraph design and Fig. 2c and Fig. 2d a (semi-)circular design, as can be found in typical pointer instruments, e.g. a manometer.

[0023] The display devices 1 each have a display area 2, which consists of individual display segments 3. These display segments 3 serve to graphically represent the process value by activation, e.g. by lighting up or by other optical highlighting or making it visible, so that the user can read or classify it, e.g., on the basis of a scale 5 arranged parallel to the display area 2 or a color code.

[0024] If, as in Fig. As shown in Figure 1, the process values ​​exhibit a high degree of fluctuation. The measured values ​​are displayed in the display area 2 by activating a span of several display segments 3. The dashed lines graphically represent the maximum and minimum values ​​of Fig. 1 on Fig. 2a / 2b. The area 4 between the maximum and minimum values ​​is then visually highlighted. The difference between Fig. 2a and Fig. 2b consists of the fact that in Fig. 2a Additionally, the moving average of the process values ​​determined during this time is displayed by activating a display segment 3. The same applies to the Fig. 2c and Fig. 2d.

[0025] Whether a high level of fluctuation is present is determined by comparison with a predefined threshold. This threshold can, for example, be determined by the rate of change of at least one display segment 3, which in the "normal case" shows the current process value. If, visually speaking, the rate of change of the currently activated display segments 3 exceeds a certain value, thus making it difficult for the human eye to read, the display device 1 switches to a mode in which the entire range 4 between the maximum and minimum values ​​is displayed, i.e., visually highlighted. Accordingly, the display device 1 reverts to its original mode, in which only one display element 3 is activated, when the threshold is no longer exceeded and thus the high level of fluctuation in process values ​​is no longer present.Advantageously, an adjustable hysteresis is provided so that switching between modes is not too rapid when values ​​are around the threshold.

[0026] Fig. Figure 3 shows a manometer as a specific embodiment of the display device 1 according to the invention. In the display area 2, the process value, in this case the pressure measurement, is represented by an activated display segment 3 and can be read by the user using the scale 5. Should the previously described situation arise, in which the process values ​​exhibit a high degree of fluctuation, the measured values ​​are displayed by activating, i.e., optically highlighting, a defined area 4 of several display segments 3 in the display area 2, and a single display segment 3 represents the moving average of the process values ​​in contrast to the defined area 4. Reference symbol list 1 Display device 2 Display area 3 Display segment 4 span area 5 scale

Claims

Display device (1) for displaying process values, comprising: - a display area (2) with several display segments (3), wherein the display of a process value is effected by activating at least one display segment (3), - means for determining the fluctuation dynamics of the process values ​​in a time unit t, - means for monitoring the fluctuation dynamics with respect to a predetermined threshold value, wherein, when the threshold value is exceeded, the display of the process values ​​between their min-max limits in the time unit t is effected by activating a spanned area (4) of several display segments (3), characterized in that the threshold value is determined as a function of the rate of change of the at least one display segment (3) for displaying the process value. Display device (1) according to claim 1, comprising means for determining a moving average of the process values ​​during the time unit t, wherein the moving average of the process values ​​is displayed as a single display segment (3) in contrast to the spanned area (4). Display device (1) according to one of the preceding claims, wherein an optional configurable damping is provided to change the process value so that the span area is reduced. Display device (1) according to one of the preceding claims, comprising a hysteresis for stabilizing the switch-on and switch-off time of the setup of the display area (2). Display device (1) according to one of the preceding claims, comprising a scale (5), wherein the activated display segment (3) points to the scale (5). Display device (1) according to one of the preceding claims, wherein the display device (1) is designed as a manometer.

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