METHOD FOR OPERATING AN OPTOELECTRONIC PRESSURE OR CONTROL ELEMENT

Description

[0001] The invention relates to a method for operating at least one optoelectronic touch or control element arranged behind an optically transparent control panel of a field device of automation technology for detecting an actuation of the optoelectronic touch or control element by an operator of the field device.

[0002] In process engineering as well as in automation technology, field devices are often used to record and / or influence process variables. Measuring devices such as level gauges, flow meters, pressure and temperature gauges, pH meters, conductivity meters, etc. are used to record process variables and record the corresponding process variables such as level, flow, pressure, temperature, pH value or conductivity. Actuators such as valves or pumps are used to influence the process variables and can, for example, change the flow of a liquid in a pipeline or the level of a medium in a container. Field devices are essentially all devices that are used close to the process and that supply or process process-relevant information.

[0003] An optoelectronic control element can be used as a replacement for mechanically operated buttons, switches, levers, and other control elements. However, due to the wide variety of applications of field devices, it is difficult to ensure reliable detection of a "button press" on such an optoelectronic control element. This is further complicated by the fact that the control panel can be made of different materials. For example, glass control panels can be used for use in potentially explosive atmospheres, whereas plastic control panels are used for field devices not designed for use in potentially explosive atmospheres.Since the control panels are usually embedded in the field device cover, and the cover can also be replaced on field devices, it cannot necessarily be assumed that the same cover will remain with the device throughout its entire life cycle. Environmental influences or conditions, such as the intensity of sunlight, or even scratches and dirt, can make reliable detection of a keystroke difficult.

[0004] EP 2 955 850 A1, DE 10 2015 003771, and US 2013 / 182246 are known from the prior art. EP 2 955 850 A1 discloses an optical switch, a field device for automation technology, and a method for controlling an optical switch. DE 10 2015 003771 discloses a method for controlling an electronic device equipped with sensor components and an associated device. US 2013 / 182246 discloses a sensor or system for recognizing gestures.

[0005] The invention is therefore based on the object of enabling reliable detection of a "key press" in an optoelectronic control element behind a control panel of a field device in automation technology.

[0006] The object is achieved according to the invention by the method according to patent claim 1 and the field device of automation technology according to patent claim 13.

[0007] The method according to the invention for operating at least one optoelectronic touch or control element arranged behind an optically transparent control panel of a field device of automation technology for detecting an actuation of the optoelectronic touch or control element by an operator of the field device provides the following method steps: a.) Detecting whether the automation technology field device is located indoors or outdoors; b.) Defining an evaluation condition that is used to detect actuation of the optical touch or control element, wherein if it is detected that the field device is located indoors, a first evaluation condition is used and if it is detected that the field device is located outdoors, a second evaluation condition different from the first is used; c.) Detecting or evaluating whether the optoelectronic touch or control element has been actuated based on the defined evaluation condition, wherein for the first evaluation condition, a value that is dependent on the time profile of an output signal originating from the optoelectronic touch or control element is used in relation to a current value of the output signal to detect actuation of the optoelectronic touch or control element.operating element and, in the second evaluation condition, a value independent of the temporal course of the output signal, particularly during measuring operation of the field device, is set in relation to a current value of the output signal to detect the actuation of the optoelectronic pushbutton or operating element.

[0008] An advantageous embodiment of the method according to the invention provides that, in order to detect an actuation of the optoelectronic pushbutton or operating element based on the first evaluation condition, an actuation is detected if the current value of the output signal is greater than a value representing the temporal course of the output signal.

[0009] A further advantageous embodiment of the method according to the invention provides that, in the second evaluation condition, a value representing an environmental condition, in particular a value representing ambient electromagnetic radiation, is further related to a current value of the output signal. In particular, the embodiment can provide that, to detect an actuation of the optoelectronic pushbutton or control element based on the second evaluation condition, an actuation is detected if a difference between the current value of the output signal and the value representing the environmental condition is greater than the value independent of the temporal profile of the output signal.

[0010] A further advantageous embodiment of the method according to the invention provides that, before detecting or evaluating whether an actuation of the optoelectronic touch or control element has occurred, the material of the control panel is first determined, and the detection or evaluation of whether an actuation of the optoelectronic touch or control element occurs is dependent on the material of the control panel. In particular, the embodiment can provide that, depending on the determined material of the control panel, a value dependent on the control panel material is used when detecting or evaluating whether an actuation of the optoelectronic touch or control element has occurred.

[0011] A further advantageous embodiment of the method according to the invention provides that a calibration value serves as the value independent of the temporal profile of the output signal. This calibration value is recorded and stored during the manufacture or production of the field device, preferably individually for each optoelectronic touch or control element. For this purpose, a replica of a field device cover made of plastic or glass can be used during production.

[0012] A further advantageous embodiment of the method according to the invention provides that the adjustment value, which serves as a value independent of the temporal progression of the output signal, is adjusted during the measuring operation of the field device. In particular, the embodiment provides that the adjustment is carried out in such a way that it is first determined during the measuring operation of the field device whether a condition exists that allows adjustment, and only when such a condition exists is the adjustment carried out.

[0013] A further advantageous embodiment of the method according to the invention provides that the value representing the ambient condition, in particular the value representing the electromagnetic ambient radiation, is used to determine whether a condition exists that allows adaptation.

[0014] A further advantageous embodiment of the method according to the invention provides that, in the event that a state exists which allows an adaptation, the adjustment value is adapted to a current value of the output signal or a value representing the temporal course of the output signal originating from the optoelectronic push-button or control element.

[0015] The invention further relates to a field device of automation technology comprising at least: a preferably transparent operating panel which has a touch surface on the outside of a housing of the field device for actuation by a user; at least one optoelectronic touch or operating element arranged on the inside of the operating panel, with at least one transmitting unit which is arranged on an inside of the operating panel facing away from the outside and is designed to transmit an optical signal in the direction of the operating panel, and with at least one receiving unit corresponding to the at least one transmitting unit for receiving the optical signal, wherein the receiving unit is arranged on the inside of the operating panel in such a way that an optical signal scattered on the operating panel by a finger of the user or another scattering object reaches at least partially the at least one receiving unit, wherein the optoelectronic touch or operating elementThe control element is further configured to detect the intensity of the optical signal incident on the receiving unit based on the received optical signal and to provide an output signal dependent thereon; an evaluation unit configured to carry out at least method steps a) to c) according to the method according to the invention.

[0016] An advantageous embodiment of the field device according to the invention further provides a light sensor or photodetector which is configured to output a signal representing an environmental condition, in particular a signal representing electromagnetic ambient radiation, and wherein the evaluation unit is further configured to relate the value representing the environmental condition to a current value of the output signal of the optoelectronic touch or control element based on the signal.

[0017] The invention is explained in more detail with reference to the following drawings. It shows: Fig. 1 : a schematically simplified view of a field device in automation technology, and Fig. 2 : a flow chart of the method according to the invention.

[0018] Figure 1 shows a schematic and highly simplified view of a field device in automation technology. The field device consists of a field device housing 130 and a field device cover 140 attached to it. The cover 140 is typically attached to the housing 130 by screwing the cover onto the housing. The cover has a partially transparent operating panel 103, which enables the operation of an optoelectronic touch or operating element 101, 102 located behind it by touching the operating panel 103 with a finger.

[0019] Depending on the intended use of the field device 100, the field device cover 140 and / or the control panel 103 are made of a different material. For use in a potentially explosive atmosphere, for example, the control panel 103 is made of glass, whereas for use outside of a potentially explosive atmosphere, the control panel 103 can also be made of a transparent plastic.

[0020] To detect an actuation of the optoelectronic touch or control element ("key press"), the control panel 103 can be optically scanned from the inside by the optoelectronic touch or control element. For optical scanning of the control panel 103, at least one optoelectronic touch or control element is provided on the inside of the control panel 103. This element consists of at least a transmitting unit 101, for example, in the form of an infrared diode, and a receiving unit 102, for example, in the form of a photodiode.

[0021] The invention is not limited to a single optoelectronic touch or control element. Typically, a series of optoelectronic touch or control elements are used to implement multiple buttons. For example, three optoelectronic touch or control elements arranged in series can be used to implement a three-button control element. The optoelectronic touch or control elements each have a transmitting unit 101 configured to transmit an optical signal and a receiving unit 102 configured to receive the optical signal.

[0022] The transmitting unit 101 for transmitting the optical signal can, for example, be configured to transmit an optical signal in the infrared spectral range. This can be implemented, for example, by a light-emitting diode or a laser diode.

[0023] The receiving unit 102 for receiving the optical signal can, for example, comprise an infrared receiving diode, preferably a PIN diode, and an AD converter that digitizes a PIN diode current originating from the receiving diode for further processing. The receiving unit 102 is arranged within a radiation range defined by the light 109 emitted by the transmitting unit 101 and the light 109 diffusely scattered on the control panel 103 when a finger is applied.

[0024] Both the transmitting unit 101 and the receiving unit 102 can be arranged on a circuit board 104. The receiving unit 102 is arranged on the operating panel 103 in such a way that, if a user's finger 105 or another scattering object touches the operating panel 103 in the control panel area or at least comes very close to it, the scattered optical signal 109 reaches at least partially the receiving unit 102.

[0025] The transmitting unit and the receiving unit 101, 102 together form a first transmitting / receiving pair, with the aid of which a first control panel area can be scanned, thus creating a first optical button. The optoelectronic control element can also have several optical buttons arranged next to one another and / or one above the other in the form of a control panel. Each optical button is formed by a further transmitting / receiving pair, which scans the corresponding further control panel. Thus, the optoelectronic control element can have a plurality of transmitting / receiving units, which operate in principle analogously to the previously described transmitting / receiving pair.

[0026] When the user touches the control panel 103 above the transmitter unit 101 in the designated control panel area with the finger 105, the optical signal 108 emitted by the transmitter unit 101 is diffusely scattered at the finger 105. In this case, the finger 105 acts as a scattering body. When the control panel 103 is touched at the corresponding point, a portion of the optical signal 108 emitted by the transmitter unit 101 reaches the receiver unit 102. This is shown in Fig. 1 represented by the arrow 109. The receiving unit 102 detects the intensity of the optical signal incident upon it and generates an output signal dependent thereon.

[0027] Furthermore, the field device has an evaluation unit 110, which can also be located, for example, on the circuit board 104. However, the evaluation unit can also be designed as part of the optoelectronic touch or control element, i.e., be integrated into it.

[0028] In addition, the field device may comprise a light sensor or photodetector 120, which is configured to output a signal representing an ambient condition, in particular a signal representing electromagnetic ambient radiation, so that an intensity of the ambient light can be detected.

[0029] The evaluation unit is designed to carry out the method according to the invention. Fig. 2 shows a flow chart of the process for clarification.

[0030] In a first method step, it is determined whether the field device of the automation technology is located in an indoor or outdoor area of ​​the automation technology. For this purpose, the evaluation unit 110 can access the signal representing the ambient condition originating from the photodetector 120. For example, if a certain value of the signal is exceeded, the evaluation unit can determine that the field device is located in an outdoor area.

[0031] In a second method step, an evaluation condition used to detect the actuation of the optical touch or control element can be determined by the evaluation unit 110 depending on the location of the field device 100. If it has been detected that the field device 100 is located indoors, the evaluation unit 110 can be configured to use a first evaluation condition, and if it has been detected that the field device is located outdoors, the evaluation unit 110 can be configured to use a second evaluation condition different from the first for detecting a "key press."

[0032] In a third optional method step, the material from which the control panel 103 is made can be determined. This can be done, for example, by accessing information about the material of the control panel 103. The information about the material can be stored, for example, in a non-volatile memory arranged in the field device housing 130 or the field device cover 140. The information can, for example, have been stored by the field device manufacturer during the production of the field device 100, so that it can be retrieved as needed, for example, by the evaluation unit 110.

[0033] In a fourth method step, the evaluation unit 110 detects or evaluates whether an actuation of the optoelectronic touch or control element 101, 102 has occurred based on the evaluation condition defined in the second method step.

[0034] For this purpose, in the first evaluation condition, a value dependent on the temporal profile of the output signal originating from the optoelectronic push-button or control element is set in relation to a current value of the output signal. For example, an average value can be calculated from the values ​​of the temporal profile of the output signal originating from the optoelectronic push-button or control element 101, 102. Alternatively, a moving average value can also be calculated from the values ​​of the temporal profile of the output signal originating from the optoelectronic push-button or control element.This value is then compared with a current value of the output signal according to the second evaluation condition and in the case that the current value of the output signal is greater than or equal to the value representing the time course, a "key press" is detected and in the case that the current value of the output signal is lower, no "key press" is detected.

[0035] In contrast, in the second evaluation condition, a value independent of the temporal profile of the output signal, particularly during the actual measuring operation of the field device, is set in relation to a current value of the output signal to detect the "key press." For example, a calibration value generated during the production or manufacture of the field device by the field device manufacturer can serve as a value independent of the temporal profile of the output signal. Such a value can, for example, be generated individually for each optoelectronic push-button or control element. In order to be able to access the calibration value(s) generated during production or manufacture during measuring operation, this value(s) can be stored in a non-volatile memory of the field device.

[0036] In addition, it can be provided that the calibration value not generated during the actual measuring operation is adjusted, i.e. changed, during the actual measuring operation. In this case, the evaluation unit can, for example, be set up to first check during the actual measuring operation whether a state currently exists that allows an adjustment of the calibration value. This can be done by using the signal representing the ambient condition, in particular the signal representing the ambient electromagnetic radiation. For example, the temporal progression of the signal can be used to determine whether there is currently no change in the environment, e.g. from light to dark or from day to night, in order to determine a state or period of time suitable for adjusting the calibration value. Periods of time in which there is low ambient radiation, e.g. during the night, are particularly suitable for adjusting the calibration value.For example, if a change in the signal over a defined period of time is not greater than a predeterminable maximum value, a condition that allows for adjustment can be detected. The defined period of time can, for example, be greater than 60 minutes, in particular greater than 120 minutes. After a condition that allows for adjustment has been determined, the actual adjustment of the adjustment value is then carried out. For this purpose, the adjustment value is adjusted to a current value of the output signal. Alternatively, several values ​​of the temporal profile of the output signal can be combined to form a value representing the temporal profile. For example, an average can be calculated over several values ​​of the output signal and the adjustment value can be adjusted to this value. Furthermore, it can be provided that the adjustment of the adjustment value only takes place within a predetermined range, i.e.The calibration value can only be adjusted plus or minus a specified calibration value range and not beyond. Such an adjustment offers the advantage that, for example, aging of the optoelectronic button or control element and / or changes to the control panel, such as scratches or similar, can be compensated to a certain extent.

Claims

1. A method for operating at least one optoelectronic probe or control element (101, 102), arranged behind an optically transparent control panel (103) of a field device from the field of automation technology (100), in order to detect an actuation of the optoelectronic probe or control element by an operator of the field device (100), characterized in that the method exhibits the following process steps: a.) Detection of whether the field device from the field of automation technology is located indoors or outdoors; b.) Specification of an evaluation condition that is applied in order to detect the actuation of the optical probe or control element (101, 102), wherein if the system detects that the field device is located indoors, a first evaluation condition is applied, and if the system detects that the field device (100) is located outdoors, a second evaluation condition that differs from the first evaluation condition is applied; c.) Detection or evaluation of whether an actuation of the optoelectronic probe or control element (101, 102) has occurred based on the specified evaluation condition, wherein with the first evaluation condition a value is set based on the chronological course of an output signal originating from the optoelectronic probe or control element (101, 102) relative to a current value of the output signal for detection of the optoelectronic probe or control element, and wherein with the second evaluation condition a value is set that is not based, in particular during measuring operations of the field device, on the chronological course of the output signal relative to a current value of the output signal for detection of the actuation of the optoelectronic probe or control element (101, 102).

2. A method according to the preceding claim, wherein an actuation is detected based on the first evaluation condition for detection of an actuation of the optoelectronic probe or control element (101, 102) if the current value of the output signal is greater than a value that represents the chronological course of the output signal.

3. A method according to one or more of the preceding claims, wherein with the second evaluation condition a value is also set that represents an ambient condition, in particular a value that represents an ambient electromagnetic radiation relative to a current value of the output signal.

4. A method according to the preceding claim, wherein an actuation is detected based on the second evaluation condition for detection of an actuation of the optoelectronic probe or control element (101, 102) if a difference between the current value of the output signal and the value representing an ambient condition is greater than the value that is not based on the chronological course of the output signal.

5. A method according to one or more of the preceding claims, wherein prior to detection or evaluation of whether an actuation of the optoelectronic probe or control element (101, 102) has occurred, the material from which the control panel (103) is produced is first determined, as well as detection or evaluation of whether an actuation of the optoelectronic probe or control element (101, 102) has occurred based on the material of the control panel (103).

6. A method according to the preceding claim, wherein, based on the determined material of the control panel (103), a value that is based on the control panel material is applied when detecting or evaluating whether an actuation of the optoelectronic probe or control element (101, 102) has occurred.

7. A method according to one or more of the preceding claims, wherein a reference value, which is recorded and defined individually during manufacture of the field device (100), preferably for each optoelectronic probe or control element (101, 102), serves as the value that is not dependent of the chronological course of the output signal.

8. A method according to one or more of the preceding claims, wherein the reference value that serves as the value not based on the chronological course of the output signal is adjusted while the field device (100) is being used to take measurements.

9. A method according to the preceding claim, wherein the adjustment is performed in such a way that the field device (100) is first used to measure whether a condition is in place that allows an adjustment to be made and then, only when a condition of this kind is confirmed to be in place, is the adjustment actually performed.

10. A method according to at least one of the claims 3 and 9, wherein the value representing the ambient condition, in particular the value that represents the ambient electromagnetic radiation, is applied in order to determine whether a condition is in place that allows an adjustment to be made.

11. A method according to at least one of the claims 8 to 10, wherein if a condition is in place that allows an adjustment to be made, the reference value is adjusted to a current value of the output signal or to a value representing the chronological course of the output signal originating from the optoelectronic probe or control element (101, 102).

12. A field device from the field of automation technology, exhibiting at least: • a control panel (103), preferably transparent, which exhibits a touch surface on an outer surface of a field device housing (130) or a field device cover (14) for actuation by a user; • at least one optoelectronic probe or control element (101, 102), arranged on an inner side of the control panel (103), with at least one transmitter unit (101), which is arranged on an inner side of the control panel (103) that faces away from the outer surface, and which is configured to transmit an optical signal toward the control panel (103) and with at least one receiver unit (102) that corresponds to the at least one transmitter unit (101) for receiving the optical signal, wherein the receiver unit (102) is arranged on the inner side of the control panel (103) in such a way that an optical signal (109) on the control panel (103) which is diffused by one of the user's fingers or another stray object (105) still finds it way, at least in part, to the at least one receiver unit (102), wherein the optoelectronic probe or control element (101, 102) is also configured to detect the intensity of the optical signal received by the receiver unit (102) and to provide an output signal based on this as per the received optical signal; characterized in that the field device also exhibits: • an evaluation unit (110), which is configured to execute process steps a) to c) according to claim 1.

13. A field device from the field of automation technology according to the preceding claim, also comprising a light sensor / photodetector (120), that is configured to output a signal representing an ambient condition, in particular a signal representing an ambient electromagnetic radiation, and wherein the evaluation unit (110) is also configured to, based on the signal, set the value representing the environmental condition relative to a current value of the output signal of the optoelectronic probe or control element (101, 102).