Patent Publication Number: US-2023160738-A1

Title: Self-sufficient display for fill level and limit level measuring devices

Description:
FIELD OF INVENTION 
     The invention relates to a sensor arrangement for fill level or limit level measurement of a product or pressure measurement in a vessel, a display device for displaying measurement data of a fill level or limit level measurement by means of a sensor arrangement, a control unit for configuring a autonomous (stand-alone) display device of a sensor arrangement for level or limit level measurement of a product or pressure measurement in a vessel, the use of an autonomous display device of a sensor arrangement for the level or limit level measurement of a filling material or the pressure measurement in a container, for the display of a status of the sensor or for the detection of the container, a method for the level or limit level measurement of a filling material or the pressure measurement in a container, a program element, a computer-readable medium and a control unit. 
     BACKGROUND OF THE INVENTION 
     In modern measurement technology, measurement sensors are used to detect a target object and/or to determine specific measurement data, for example for a level or limit level measurement. The measurement data can be displayed either by a wired display unit directly on site or via mobile end devices such as a smartphone or tablet. 
     Especially if the measuring sensors are installed in several process vessels distributed in a plant, it is not always easy for a user to keep track. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an alternative measurement arrangement which facilitates the collection of important information by the user. 
     The object is solved by the features of the independent patent claims. Further embodiments of the invention result from the subclaims and the following description. 
     One aspect of the present disclosure relates to a sensor arrangement for fill level or limit level measurement of a product in a container. The sensor arrangement comprises a sensor configured to transmit and receive a measurement signal and to calculate measurement data, and an display device. The display device is spatially separated from the sensor and is configured to be mounted on or in the container. The display device comprises a receiving unit configured to wirelessly receive the measurement data of the sensor, and a signal indicator or signal display configured to display the measurement data of the sensor. 
     The sensor can, for example, be a radar sensor, in particular a non-contact measuring radar sensor for process automation in an industrial environment or for object detection. 
     The sensor can be arranged above the product, inside or outside the process vessel in such a way that the measuring signal emitted by the sensor can propagate in the direction of the product and be reflected by the surface of the product. If the sensor is arranged outside the container, the container can be made of a material that the measurement signal can penetrate. For example, the container is an IBC (intermediate bulk container) tank made of plastic. 
     Alternatively, the sensor can also be a radiometric sensor, which is arranged at the side of the container. Furthermore, the sensor can also be a pressure, temperature or flow sensor, for example. 
     The display device can be a stand-alone (autarkic, self-sufficient) display device. Alternatively, the display device can be connected to the sensor via a cable. 
     The display device or the self-sufficient display device, which is provided separately from the sensor, can be arranged flexibly, i.e. independently of the arrangement of the sensor. In particular, the self-sufficient display device can be mounted individually. For example, the self-sufficient display device can be arranged inside the container or on or in the filling material or the medium so that the self-sufficient display device can float on the filling material, for example, or can be sunk or immersed in the filling material. Alternatively, the self-sufficient display device can be arranged outside the container, on the side of the container or on an outer side of a frame to which the container is attached, so that the self-sufficient display device can be easily recognized or read from the outside. 
     The self-sufficient display device can be wirelessly connected to the sensor by means of the receiving unit and receive the measurement data from the sensor. Compared to a wired, possibly detachable indicator such as VEGAMET or VEGADIS, the sensor arrangement with the wireless self-sufficient display device can be used more flexibly and easily, for example, for monitoring or maintaining a process vessel in a plant. 
     According to an embodiment, the signal display of the display device of the sensor arrangement is set up to visually and/or acoustically display the measurement data of the sensor, and/or the status of the sensor. 
     By visually displaying by means of the signal display, the measurement data of the sensor, namely the level or the limit level of the product or the pressure inside the container, can be visually displayed. For example, the change of the measurement data of the sensor, namely the level, the limit level or the pressure can be displayed visually. In the case of acoustic display, the measurement data can be specifically signaled, for example, by emitting an acoustic signal, by emitting an acoustic warning signal when a certain fill level or a defined limit level is exceeded. Alternatively, the acoustic indication can be done by broadcast. The optical display can also be combined with the acoustic display. 
     In addition, the signal display of the sensor arrangement can be set up to identify the container associated with the sensor. For this purpose, the signal display of the display device or the stand-alone display device can be set up to visually detect the container, to identify the container or to recognize the location of the container, which is located, for example, in a system with several other containers and in which the sensor is arranged to detect the fill level or the limit level. 
     For example, the status of the sensor can be power on or power off, measurement, data processing, or a fault with the sensor. 
     Alternatively or additionally, the signal display can be set up to display individual or combined information, such as the filling material or the medium of the container assigned to the sensor or the oldest filling date, an order number, which are entered or stored on a cloud platform, for example. 
     According to another embodiment, the signal indicator is a luminous indicator. 
     Alternatively or additionally, a luminous display, which is set up to emit a light signal, can be provided in the display device. For this purpose, the light signal can correspond to the measurement data of the sensor. 
     According to a further embodiment, the luminous display is configurable by multiple colors to visually visualize the measurement data of the sensor, the status of the sensor, or switching states of the sensor. 
     The luminous display of the display device can be configurable in such a way that the luminous display of the display device can illuminate in several colors and, when illuminated or emitting a colored light signal, can specifically display or signal the measurement results of the sensor. For example, a certain color, e.g. red, can be characteristic for a predefined value range of the measurement data of the level measurement, indicate as a warning signal that the limit level has been exceeded during the limit level measurement or correspond to a certain switching state of the sensor, e.g. switching on or off. 
     Alternatively or additionally, the luminous display can be configured in such a way that the illumination can follow a predefined color gradient and thus indicate a specific measured value or a specific change in the measured value of the measurement data during the level or point level measurement. 
     The light indicator can also be configurable such that the light indicator can output a defined signal pattern. 
     The lighting can, for example, be permanent, cyclic with a predefined time interval or frequency, or following a specific prompt, such as a trigger signal, a pushbutton, or a defined fill level or limit level change. 
     The configurability of the luminous display in the multiple colors or according to the predefined color gradient or a defined signal pattern is significant and advantageous, especially when multiple containers or IBC tanks are arranged in a large plant or warehouse and the sensor arrangement includes multiple sensors, each individually installed in the multiple containers. For this purpose, the sensors may be of the same type. Or the sensors can be different sensors for level or limit level measurement, pressure measurement, or for some other measurement such as temperature or flow measurement. 
     For this purpose, a plurality of display devices, each associated with the plurality of sensors or the plurality of containers, may be provided and arranged individually. 
     For example, a clear assignment of the multiple containers in a system can be made possible or simplified by the fact that the multiple luminous indicators of the multiple display devices can be assigned by a special color or a characteristic signal pattern. Thus, for example, the containers that have the identical filling data or are filled with the same medium can be grouped and identified. 
     According to a further embodiment, the sensor arrangement further comprises a master display device, which is set up in the form of a master luminous display to display the measurement data from a plurality of sensors individually, in combination or collectively. 
     It can also be provided that the display device can be set up for combined or linked display of the measurement data of a level sensor and a limit level sensor. For example, the display device can be configured in such a way that in normal operation the fill level is continuously visualized via a color gradient and the limit level is only signaled by means of a flashing signal when the limit switch is switched on or the fill level exceeds a certain level. 
     Furthermore, a display device or a stand-alone display device, which can also serve as a common master display device used by several sensors, can be provided and set up to display the measurement data of the several sensors individually, in combination or collectively. Thus, simultaneous monitoring and visualization of the statuses of the multiple sensors, the fill or limit levels of the products in the multiple containers, and/or the fill data of the multiple containers can be enabled. 
     The indicator light may be configurable to prioritize the indication of a critical sensor status, such as the sensor malfunctioning, or a critical reading of the sensors measurement data. 
     The configuration of the luminous display can be carried out ex works or on site in the plant. This means that the assignment of the stand-alone display device to the sensor, the sensor arrangement and/or the container, the integration of the stand-alone display device in the cloud system and/or the connection to the other display devices in the networked plant for displaying the measurement data of the sensor and/or for addressing the container can be preconfigured ex works or set on site. 
     In addition, a communication device, for example for a commissioning system, or a monitoring device can be provided in the plant, which has a mobile eye-catching module and can be set up to record and evaluate the displayed signal of the luminous display of the sensor arrangement. The communication device may be of mobile design. 
     According to a further embodiment, the display device comprises an encapsulation adapted to encapsulate the display device in order to arrange the display device within the container or on or in the filling material. 
     The encapsulation may be designed to be watertight to enclose the indicating device. In particular, when the indicator is located on or in the filling material within the container, the encapsulation may serve to protect the indicator from the ingress of the water. 
     In the system with the multiple containers, the assignment of one of the multiple containers can be made even if the luminous indications of the indicating devices are arranged inside the container, on or in the filling material. The containers can transmit the colored light beams of the luminous indicators. 
     According to a further embodiment, the self-contained display device comprises a power supply comprising a rechargeable battery or a battery. Further, the power supply is arranged in the self-contained display device and is arranged to provide the power required to operate the self-contained display device. 
     The self-sufficient display device is a display device that can obtain the energy required to operate the display device not by wire from an external energy source, but from an internal energy source. The power supply may be arranged or incorporated as an internal component in the form of an accumulator or battery in the self-contained display device. The energy supply or battery may be charged inductively from the outside or wirelessly using energy harvesting. Alternatively, the energy supply can be charged by cable at a charging station and the stand-alone display unit can be used with the charged energy supply for level or limit level measurement. 
     According to a further embodiment, the stand-alone display device is arranged to be connected to the sensor via a direct radio link or a cloud system. 
     The sensors measurement data can be transmitted to the stand-alone display device via a wireless connection, such as LPWAN, Bluetooth, WLAN, LoraWan, NB-IOT. 
     Alternatively or additionally, the wireless connection or communication between the stand-alone display device and the sensor can take place via a cloud system, a central computer or a control level. The measurement data from the sensor may be transmitted from the sensor to the cloud system and then from the cloud system to the corresponding stand-alone display device. It may also be possible that the measurement data transmitted from the sensor can be further processed on the cloud system, that only a selected portion of the measurement data can be transmitted to the stand-alone display device for display. 
     Advantageously, the cloud system can enable the multiple sensors in a plant to be connected to the multiple stand-alone display devices and/or to a master display device. Thus, a networked plant can be formed with the multiple process vessels by means of the sensor arrangement. Combined with the configurability of the master display device and/or the plurality of autonomous display devices, the sensor arrangement can be advantageously deployed or used in the process industry, process automation and/or automation technology. 
     The term automation technology is understood to be a subfield of technology that includes all measures for the operation of machines and plants without the involvement of humans. One goal of the related process automation is to automate the interaction of individual components of a plant in the chemical, food, pharmaceutical, petroleum, paper, cement, shipping or mining industries. For this purpose, a variety of sensors can be used, which are especially adapted to the specific requirements of the process industry, such as mechanical stability, insensitivity to contamination, extreme temperatures and extreme pressures. Measured values from these sensors are usually transmitted to a control room, where process parameters such as level, limit level, flow rate, pressure or density can be monitored and settings for the entire plant can be changed manually or automatically. 
     One subfield of automation technology concerns logistics automation. With the help of distance and angle sensors, processes within a building or within an individual logistics facility are automated in the field of logistics automation. Typical applications include systems for logistics automation in the area of baggage and freight handling at airports, in the area of traffic monitoring (toll systems), in retail, parcel distribution or also in the area of building security (access control). Common to the examples listed above is that presence detection in combination with precise measurement of the size and location of an object is required by the respective application side. Sensors based on optical measurement methods using lasers, LEDs, 2D cameras or 3D cameras that measure distances according to the time-of-flight (ToF) principle can be used for this purpose. 
     Another subfield of automation technology concerns factory/production automation. Application cases for this can be found in a wide variety of industries such as automotive manufacturing, food production, the pharmaceutical industry or generally in the field of packaging. The goal of factory automation is to automate the production of goods by machines, production lines and/or robots, i.e. to let it run without the participation of humans. The sensors used in this process and the specific requirements with regard to measuring accuracy when detecting the position and size of an object are comparable to those in the previous example of logistics automation. Therefore, sensors based on optical measurement methods are usually also used on a large scale in the field of factory automation. 
     In the field of logistics automation, as well as in the field of factory automation and safety technology, optical sensors have dominated up to now. These are fast (fast filling processes with more than 10 measurements/second) and inexpensive and can reliably determine the position and/or distance to an object due to the relatively easy focusable optical radiation, which is the basis of the measurement. 
     According to a further embodiment, the sensor arrangement comprises a control unit. The control unit is set up to connect to the display device by wire or wirelessly and to configure the display device to activate the display device cyclically at a predetermined time interval or by a trigger signal. 
     The control unit can be connected locally to the display device by wire or cable in order to configure the stand-alone display device. For this purpose, a corresponding connection can be provided in the display device to accommodate the control unit. Alternatively or additionally, the control unit may connect wirelessly to the display device by radio or via the cloud system. The control unit may be designed as a mobile operating device and may be integrated in the networked system or in the networked sensor arrangement. 
     The control unit can be set up to configure the display device of the sensor arrangement in such a way that the signal display can display the measurement data of the sensor, the status of the sensor visually and/or acoustically, and to signal the luminous display with a defined color, according to a specific signal pattern or color gradient, cyclically with a predetermined time interval and/or by a trigger signal, such as a broadcast command, in a targeted manner. 
     According to a further embodiment, the control unit is set up to send out a broadcast command. Alternatively or additionally, the display device or the master display device is set up to display the measurement data of the sensor or the multiple sensors simultaneously by the broadcast command. 
     In the system with the multiple containers and the sensor arrangement with the multiple display devices, the control unit can be designed as a master operating device and thus be connected to the multiple autonomous display devices. 
     Further, it may be possible for the control unit to receive a signal emitted by the cloud system as a trigger signal for activating one or more of the display devices. Alternatively, a master display device may be integrated into the control unit. Thus, receiving data from the cloud system and configuring the plurality of display devices can be uniformly controlled based on the received measurement data. Thus, the automation of the sensor arrangement in the process plant can be optimized. 
     Another aspect of the present disclosure relates to a display device for displaying measurement data of a level or limit level measurement or a pressure measurement by means of a sensor arrangement. 
     Another aspect of the present disclosure relates to a control unit for configuring a stand-alone display device of a sensor arrangement for level or point level measurement of a product or pressure measurement in a container. 
     Another aspect of the present disclosure relates to the use of a self-contained display device of a sensor arrangement for level or limit indication of a filling material or pressure indication in a container, for displaying a status of the sensor or for detecting the container. 
     Another aspect of the present disclosure relates to a method for level or point level measurement of a product or a pressure measurement in a vessel. The method comprises the following steps: Transmitting and receiving a measurement signal by means of a sensor and calculating measurement data, separately providing a display device for displaying the measurement data of the sensor, wirelessly receiving the measurement data from the sensor by means of a receiving unit of the display device, and displaying the measurement data of the sensor by means of a signal display of the display device. 
     According to a further embodiment, the method further comprises the steps of: wired or wirelessly connecting a control unit to the display device and configuring the display device and activating the display device cyclically with a predetermined time interval or by a trigger signal. 
     Another aspect of the invention relates to a program element which, when executed on a processor of a sensor arrangement, instructs the sensor arrangement to perform the following steps: Transmitting and receiving a measurement signal by means of a sensor and calculating measurement data, separately providing a display device for displaying the measurement data of the sensor, wirelessly receiving the measurement data of the sensor by means of a receiving unit of the display device, and displaying the measurement data of the sensor by means of a signal display of the display device. 
     Further, the program element may instruct the sensor arrangement to perform the further steps of: wired or wirelessly connecting a control unit to the display device and configuring the display device and activating the display device cyclically with a predetermined time interval or by a trigger signal. 
     Another aspect of the invention relates to a computer-readable medium on which a program element is stored. 
     Another aspect of the invention relates to a control unit on which a program element is stored. 
     In the following, further embodiments of the present disclosure are described with reference to the figures. Where identical reference signs are used in the following description of figures, these designate identical or similar elements. The representations in the figures are schematic and not to scale. 
    
    
     
       SHORT DESCRIPTION OF THE FIGURES 
         FIG.  1    shows a schematic diagram of a sensor arrangement for level or point level measurement according to an embodiment. 
         FIG.  2    shows a schematic diagram of a sensor arrangement for level or point level measurement according to a further embodiment. 
         FIG.  3    shows a schematic representation of a stand-alone display device according to an embodiment. 
         FIG.  4    shows a schematic representation of the communication paths within a sensor arrangement according to an embodiment. 
         FIG.  5    shows a schematic diagram of the arrangement of a stand-alone display device in a system according to an embodiment. 
         FIG.  6    shows a schematic diagram of the arrangement of a control unit in a system according to an embodiment. 
         FIG.  7    shows a flow diagram of a method for level or point level measurement of a product according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLES OF EXECUTION 
       FIG.  1    shows a schematic diagram of a sensor arrangement  900  for level or point level measurement of a filling material (product)  55  in a container  50 . 
     The sensor arrangement  900  includes a sensor  20  and a display device or self-contained display device  100  provided separately from the sensor  20  and wirelessly connected to the sensor  20 . 
     In order to perform the fill level or limit level measurement, the sensor  20  is configured to transmit and receive a measurement signal and to calculate measurement data. The sensor  20  may be a radar sensor. The measurement signal emitted by the sensor  20  may propagate in the direction of the product  55  or the medium contained in an IBC container  50 , for example, and may be reflected from the surface of the product  55 . The IBC container  50  is arranged and secured in a steel frame  10  or strut and includes a lid  52  to form a closed interior for the contents  55 . The IBC container  50  may be made of a plastic material to allow the wall of the container  50  to pass the measurement signal from the sensor  20 . 
     The sensor  20  can communicate wirelessly with the self-sufficient display device  100 , which can be provided as an independent component of the sensor arrangement  900  separate from the sensor  20 . As a result, the self-sufficient display device  100  can be arranged independently of the arrangement of the sensor  20 , flexibly, namely inside the container  50  as shown in  FIG.  1    or outside the container  50  as shown in  FIG.  2   . 
     As shown in  FIG.  3   , the self-sufficient display device  100  comprises a receiving unit  110  arranged to wirelessly receive measurement data from the sensor  20  and a signal display  180  arranged to display the measurement data from the sensor  20 . The schematic diagram of the self-sufficient display device  100  shown in  FIG.  3    is described in more detail below. 
       FIG.  1    further shows that the self-sufficient display device  100  can be arranged within the container  50  or in such a way that the self-sufficient display device  100  can be arranged on or in the filling material  55  or the medium. For example, the self-sufficient display device  100  can float on the filling material  55  or be submerged in the filling material. For this purpose, the self-sufficient display device  100  may comprise an encapsulation adapted to encapsulate the self-sufficient display device  100  to provide waterproof protection to the display device  100 . The self-sufficient display device  100  arranged on or in the filling material  55  may comprise a luminous display and be arranged to emit and signal a light signal  101  in the form of a light beam or a light bundle out through the container  50  based on the measurement data received from the sensor  20 . 
     Alternatively, the self-sufficient display device  100  may be arranged outside the container  55 . Compared to  FIG.  1   , the self-sufficient display device  100  in  FIG.  2    can be arranged on the side of the container  50  or on the outside of the frame  10 . Thus, the sensor arrangement  900  can advantageously display the measurement data of the sensor  20  and to optimize the detectability or readability of the self-contained display device  100 . 
     In  FIG.  1   , the measurement data can be transmitted from the sensor  20  to the self-sufficient display device  100  via a wireless connection, such as Bluetooth, WLAN, LoraWan, NB-IOT. Alternatively or additionally, as shown in  FIG.  2   , wireless communication between the self-sufficient display device  100  and the sensor  20  may be via a cloud system  200 , a central computer, or a control plane. 
       FIG.  3    shows a schematic representation of the self-sufficient display device  100  of the sensor arrangement  900 . In addition to the receiver unit  110  and the signal display  180 , the self-sufficient display device  100  further comprises a power supply  120  and electronics  150 . 
     The receiving unit  110  of the stand-alone display device  100  may be set up to wirelessly receive the measurement data from the sensor  20 , for example by radio or via a cloud system  200 . The receiving can be performed permanently, cyclically with a predetermined time interval or activating by a trigger signal. 
     The electronics  150  of the self-contained display device  100  may be in the form of a circuit board, for example, so that the receiver unit  110 , the power supply  120 , and the signal display  180  may be arranged on the electronics  150  and electrically connected via the electronics  150 . 
     The power supply  120  is a built-in of the self-contained power supply unit disposed within the display device  100  to wirelessly provide the power required to operate the self-contained display device  100 . The power supply  120  may comprise a battery or a rechargeable battery that may be externally charged, for example, inductively. 
     Alternatively or additionally, the battery may be charged using energy harvesting. It is also possible that the self-sufficient display device  100  can be charged by means of the energy supply  120  by cable at a charging station and can then be used to display the measurement data. 
     The signal display  180  of the stand-alone display device  100  may be configured to display the measurement data of the sensor  20 . For this purpose, the signal display  180  can be set up for visually and/or acoustically displaying the measurement data of the sensor  20 , and/or for visually and/or acoustically displaying the status of the sensor  20 , and/or for identifying the container  50  assigned to the sensor  20  for identification. 
     Alternatively or additionally, the signal display  180  of the stand-alone display device  100  may be a luminous display. In this case, the luminous display can be designed to be configurable by several colors in order to visually visualize the measurement data of the sensor  20  or switching states of the sensor  20 . For example, the luminous display  100  can be activated or switched on permanently, cyclically or by a trigger signal, such as a radio signal, a pushbutton, a defined fill level or limit level change. 
       FIG.  4    shows a schematic diagram of the communication paths within a sensor arrangement  900 . 
     The sensor arrangement for level or point level measurement further comprises a control unit  310 ,  320  configured to connect wired or wirelessly to the self-sufficient display device  100  and thus configure the self-sufficient display device  100  to activate the self-sufficient display device  100  cyclically at a predetermined time interval or by a trigger signal. The control unit  320  may be locally connected to the self-sufficient display device  100 . Alternatively, the control unit  310  may be wirelessly connected to the self-sufficient display device  100  by radio or via a cloud system  200 . 
     In addition to the control unit  310 ,  320 , the self-contained display device  100  may wirelessly connect to the sensor  20  or a cloud system  200  that is also wirelessly connected to the sensor  20  and may receive measurement data from the sensor  20  via radio. Thus, the self-sufficient display device  100 , the sensor  20  and the control unit  310 ,  320  of the sensor arrangement  900  can be provided separately from each other and arranged separately. This can advantageously increase the flexible usability of the sensor arrangement in a plant with the multiple containers to be monitored and the mobility of the sensor arrangement. 
     For example,  FIG.  5    shows a schematic diagram of the arrangement of a stand-alone master display device  106  in a plant. 
     In the system, the sensor arrangement  900  in  FIG.  5    includes a plurality of sensors each disposed in one of the plurality of containers  50 ,  60 ,  70 , and a plurality of self-contained display devices  100  each associated with one of the plurality of sensors and/or one of the plurality of containers  50 ,  60 ,  70 . The sensors may be similar or different sensors for level or limit level measurement or, for example, for pressure, temperature, or flow measurement. The plurality of sensors and the plurality of autonomous display devices may be wirelessly connected via a cloud system or an IOT cloud platform, and a networked system may be formed thereby. Thus, the sensor arrangement may enable the plurality of sensors to transmit the determined or calculated measurement data to the cloud system  200 , and the plurality of autonomous display devices associated with the sensors may receive the measurement data from the cloud system  200  and display the measurement data of the plurality of sensors individually, in association, or collectively. 
     In addition, the sensor arrangement may further comprise another stand-alone display device, which may be configured as a master display device  106  to display the measurement data from the plurality of sensors via the cloud system  200 . In  FIG.  5   , the master display device  106  is provided outside the plurality of containers  50 ,  60 ,  70 . Since the measurement data of the plurality of sensors is accessible in the cloud system  200 , the master display device  106  may be configured to display the measurement data or sensor status of a targeted sensor or in a composite of the plurality of sensors, and to monitor the level or limit level in a targeted container or in the plurality of containers. 
       FIG.  6    shows a schematic diagram of the arrangement of a control unit  300  in a system according to one embodiment. 
     Similar to  FIG.  5   , the sensor arrangement  900  in the system includes a plurality of sensors each disposed in one of the plurality of containers  50 ,  60 ,  70 , and a plurality of self-sufficient display devices  100  each associated with one of the plurality of sensors and/or one of the plurality of containers  50 ,  60 ,  70 . The plurality of sensors and the plurality of self-sufficient display devices may be wirelessly connected via a cloud system. Thus, it is possible for the plurality of sensors to transmit the determined or calculated measurement data to the cloud system  200 , and for the plurality of self-sufficient display devices associated with the sensors to receive the measurement data from the cloud system  200  and individually display the measurement data. 
     The control unit  300  in  FIG.  6    is configured to connect wired or wirelessly to the plurality of self-contained display devices and to configure the plurality of self-contained display devices  100  to activate the self-contained display device cyclically at a predetermined time interval or by a trigger signal. In other words, the control unit  300  may be in the form of a master operating device. The connection between the control unit  300  and the plurality of self-sufficient display devices respectively associated with the plurality of containers  50 ,  60 ,  70  may be by cable or wirelessly by radio. 
     Further, the control unit  300  may be configured to be wirelessly connected to the cloud system  200  and to receive a signal emitted by the cloud system  200  as a trigger signal for activating a display device or the plurality of stand-alone display devices. Alternatively, a master display device  106 , as shown in  FIG.  3   , may be integrated into the control unit  300 . Thus, receiving data from the cloud system  200  and configuring the plurality of self-sufficient display devices can be uniformly controlled based on the received measurement data. 
       FIG.  7    shows a flowchart of a method for level or limit level measurement of a product  55  in a container  50 . In the first step  701 , a measurement signal is transmitted and received by means of a sensor  20  of a sensor arrangement  900 , and the measurement data is calculated based on the measurement signal. In step  702 , a self-sufficient display device  100  having a receiving unit  110  and a signal display  180  is separately provided to the sensor arrangement  900  for displaying the measurement data of the sensor. Thus, the self-sufficient display device  100  can be flexibly arranged inside or outside the container independently of the arrangement of the sensor  20 . In step  703 , the measurement data from the sensor  20  is wirelessly received by means of the receiving unit  110  of the self-sufficient display device  100 . In this regard, the receiving may be performed via a wireless connection or a cloud system  200 . In step  704 , the measurement data from the sensor  20  is displayed by means of the signal display  180  of the self-contained display device  100 . 
     Further, in step  705 , a control unit  300 ,  310 ,  320  of the sensor arrangement  900  is connected to the self-sufficient display device  100  in a wired or wireless manner. Subsequently, in step  706 , the self-sufficient display device  100  is configured by the control unit  300 ,  310 ,  320  and activated cyclically with a predetermined time interval or a trigger signal. 
     Supplementally, it should be noted that “comprising” or “having” does not exclude other elements, and “a” or “an” does not exclude a plurality. It should further be noted that features described with reference to any of the above embodiments may also be used in combination with other features of other embodiments described above. Reference signs in the claims are not to be regarded as a limitation.