Display device for displaying process values

Abstract

The invention relates to a display device (1) for displaying process values, comprising: a display region (2) having a plurality of display segments (3), a process value being displayed 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 specified threshold value. If the threshold value is exceeded, the process values are displayed between the min / max limits thereof in the time unit t by activating, i.e. optically highlighting, an area (4) defined by a plurality of display segments (3).

Description

[0001] Display device for showing process values

[0002] The present invention relates to a display device for showing process values.

[0003] 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 designed as a plug connector.

[0004] Simultaneously, measured values ​​can be transmitted, e.g., as a 4-20 mA signal, to an external control unit, such as a PLC. Such a display device is shown, for example, in German patent DE 102009017783 B4 of the applicant.

[0005] 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.

[0006] Various approaches are known in the prior art to improve the representation of measured values ​​beyond a mere display of values.

[0007] One approach addresses the problem of a limited analog display range. For example, US 6,412,187 B1 describes a display device in which the display range is automatically shifted (auto-ranging) to ensure that a single peak value remains within the visible scale.

[0008] Other approaches focus on the visual evaluation of a single, current measurement. For example, German patent DE 102018126790 A1 demonstrates the use of predefined rating ranges on a display to classify a measurement as "good" or "bad." JP 2018-136165 A takes a similar approach, visualizing the deviation of a current measurement from an ideal mean by a color-coded range. These known solutions share the commonality of either focusing on managing the display window for a single value or evaluating a single, current measurement in relation to static reference points or ranges.

[0009] The object of the invention is to propose a display device in which readability is improved even with high fluctuations in process values. This object is achieved by a display device with the features of claim 1. Advantageous embodiments of the invention are specified in the dependent claims.

[0010] The display device according to the invention comprises a display area consisting of several display segments, and the activation of at least one display segment represents a process value. The invention is characterized in that it includes means for determining and monitoring the fluctuation dynamics of the process values ​​within a time unit t. In the event of strong fluctuation dynamics exceeding a predetermined threshold, the device switches to a special display mode (hereinafter also referred to as 'dynamic display mode'). In this mode, the process value is no longer displayed as a single pointer or indicator. Instead, the range within which the process value fluctuates is displayed between its values ​​during the

[0011] The minimum and maximum limits (min-max limits) of the given time unit t are displayed and visualized as a continuous, spandled area by activating multiple display segments. This significantly improves readability, as the extent of the fluctuation becomes immediately apparent to the user.

[0012] The decision as to whether there is a high degree of fluctuation that justifies switching to the dynamic display mode with the defined range is made by comparison with a predefined threshold value. This threshold value can be fixed, but is preferably determined dynamically to allow for flexible adaptation to different process conditions.

[0013] In a preferred embodiment, the threshold value is determined as a function of the rate of change of the at least one display segment, which represents the current process value during normal operation. This represents an indirect, but computationally simple method for capturing the fluctuation dynamics, as it is based directly on the visual behavior of the display. If the speed at which the activated display segments change exceeds a certain value, thus making smooth reading difficult for the human eye, this is a clear indication of high fluctuation dynamics. In an alternative, also preferred embodiment, the threshold value is determined as a function of the rate of change of the process value itself. This approach captures the fluctuation dynamics directly at the source, i.e., at the incoming measurement signal.This allows for a particularly precise determination of the dynamics, decoupled from the display logic, which can be especially advantageous when processing high-frequency signals.

[0014] To prevent unwanted, rapid switching between normal operation and dynamic display mode when the fluctuation dynamics oscillate around the threshold, a hysteresis is advantageously implemented. This ensures that the switch-on point for expanding the range occurs at a slightly higher dynamic value than the switch-off point. This stabilizes the display and provides a smooth and consistent visual experience for the user.

[0015] Preferably, a moving average of the process values ​​during the time unit t is additionally displayed as a separate display segment within the defined area. This segment can be distinguished from the defined area, for example, by higher contrast or a different color. This provides the user with two essential pieces of information at a glance: the total extent of the fluctuation across the defined area and the central trend value of the signal as represented by the moving average. This is particularly advantageous in the case of very wide fluctuations, enabling an assessment of the average process state. In a further advantageous embodiment, an optional, configurable attenuation can be provided. This attenuation acts on the process value before its minimum and maximum limits are determined.This allows the displayed area to be selectively reduced, for example to filter out high-frequency noise that is irrelevant for process monitoring. This further contributes to the stability and readability of the display and allows the display sensitivity to be adjusted to the specific measurement task.

[0016] The process value is typically displayed in relation to a scale assigned to the display range, allowing the value to be read quantitatively. The invention offers particular advantages when the display device is designed as a pressure gauge, as is typical for monitoring pressure signals in pipelines or containers, since pressure processes, such as those involving the switching of valves, are often characterized by extreme and high-frequency fluctuations.

[0017] The invention thus offers several advantages: First, readability is significantly improved by displaying the process value. Second, the visual strain on the human eye is reduced. Third, the hysteresis ensures a stable display. Fourth, the dynamic threshold allows for flexible adjustment. Fifth, even rapid, high-frequency process value fluctuations, which would be missed with conventional methods, can be detected and displayed.

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

[0019] They show schematically:

[0020] Figure 1 shows a prior art display device in normal operation; Figure 2 shows an exemplary curve of a process value with high fluctuation dynamics;

[0021] Figure 3a shows a display device according to the invention in a first, rectangular embodiment, which represents the stretched area and a moving average value;

[0022] Figure 3b shows the same display device, but only showing the stretched area; Figure 3c shows a display device according to the invention in a second, (semicircular) embodiment, which shows the stretched area and a moving average value;

[0023] Figure 3d shows the same display device in a (semi-)circular design, which only displays the stretched area;

[0024] Figure 4 shows a display device according to the invention in the specific embodiment of a manometer that is in dynamic display mode.

[0025] In the following description of preferred embodiments, identical reference numerals denote identical or comparable components.

[0026] Figure 1 shows a prior art display device 1, commonly used for displaying process values. The device 1 has a display area 2 with an associated scale 5. A single active display segment, shown here as a pointer 3, indicates the current measured value on the scale 5. This display method is well suited for stable or slowly changing process values.

[0027] Figure 2 shows an example of a process value over time, characterized by high fluctuation dynamics. This manifests as high-frequency oscillation and a large amplitude between the minimum and maximum values ​​of the signal. Such a signal profile can be observed, for example, when a valve in a pipeline opens or closes. If this signal profile were displayed with a conventional display device as shown in Figure 1, the pointer 3 would jump back and forth so quickly and erratically that a reliable reading of the current value or an understanding of the process dynamics would be virtually impossible for the user.

[0028] Figures 3a to 3d show various embodiments and modes of the display device 1 according to the invention, which solve precisely this problem. All embodiments have a display area 2 consisting of individual display segments 3. When the fluctuation dynamics shown in Figure 2 exceed a predefined threshold, the display device 1 switches from the conventional display (Fig. 1) to a dynamic display mode according to the invention.

[0029] In this mode, a single, fluctuating value is no longer displayed. Instead, the entire range within which the process value fluctuates is visualized. This is achieved by activating a span 4 that extends across multiple display segments 3. The dashed lines in the illustration indicate how the maximum and minimum values ​​shown in Figure 2 define the boundaries of the span 4 in Figures 3a and 3b. This span 4 is visually highlighted as a continuous block or band, allowing the user to immediately and intuitively grasp the extent of the fluctuation.

[0030] Figures 3a and 3b show a rectangular bargraph design, while figures 3c and 3d show a (semi-)circular design, as is found in typical pointer instruments.

[0031] Figures 3a and 3c illustrate a particularly advantageous implementation of the dynamic mode. In addition to the displayed area 4, which indicates the range of fluctuation, a moving average of the process value, calculated over the time unit t, is visualized by a single, high-contrast display segment 3. This provides the user with two essential pieces of information at a glance: the total extent of the fluctuation and the central trend value of the signal. Figures 3b and 3d show an alternative, simplified representation in dynamic mode, where only the displayed area 4 is shown for clarity.

[0032] The decision to switch to dynamic mode is made by comparing the fluctuation dynamics with a threshold value. To allow flexible adaptation to different process conditions, this threshold value is preferably determined dynamically. In one embodiment, it can depend on the rate of change of the display segment 3, which normally shows the process value. Alternatively, and more directly, it can be derived from the rate of change of the process value itself. To avoid unwanted flickering of the display at values ​​around the threshold value, a hysteresis is preferably provided to stabilize the switch-on and switch-off times of the dynamic mode. Accordingly, the display device 1 reverts to the conventional mode shown in Figure 1 when the threshold value is again undershot.

[0033] Figure 4 shows a specific embodiment of the display device 1 according to the invention as a manometer in dynamic display mode. The display area 2 with the scale 5 is visible. Instead of a single pointer, the displayed area 4 is shown as an optically highlighted band indicating the pressure fluctuation range. Within this band, a single, contrasting display segment 3 shows the moving average pressure. This display enables the user to reliably and quickly determine both the magnitude of the fluctuation and the average system pressure, even during strong pressure surges.

[0034] 1 Display device 2 Display area

[0035] 3 Display segment

[0036] 4 span range 5 scale

Claims

Patent claims 1. 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 achieved by activating at least one display segment (3), - Means for determining the fluctuation dynamics of process values ​​in a time unit t, - Means of monitoring the dynamics of fluctuations with respect to a given threshold value, where, when the threshold is exceeded, the process values ​​between their min-max limits in the time unit t are displayed by activating a spanned range (4) of several display segments (3).

2. Display device (1) according to claim 1, wherein 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.

3. Display device (1) according to claim 1, wherein the threshold value is determined as a function of the rate of change of the process value for the purpose of displaying the process value.

4. Display device (1) according to one of the preceding claims, 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).

5. 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.

6. Display device (1) according to one of the preceding claims, comprising a hysteresis for stabilizing the switch-on and switch-off time of the clamping of the clamped area (4).

7. 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).

8. Display device (1) according to one of the preceding claims, wherein the display device (1) is designed as a manometer.

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