Sensor device, control device, automation system and method of transmitting signals

Abstract

The invention relates to a sensor device. The sensor device is configured to output, in a first operating state, a sensor output signal of a sensor having an electrical logic level according to a first communication standard via a signal interface and to receive an electrical switching signal which does not correspond to the first communication standard. The sensor device is configured to be able to switch into a second operating state in dependence on the switching signal being received, in which second operating state a communication signal having a logic level according to a second communication standard can be received via the signal interface, the logic level of the first communication standard being different from the logic level of the second communication standard. The sensor device is configured to identify the switching signal in dependence on a voltage applied to the sensor device, the switching signal not corresponding to the logic level of the first communication standard. Furthermore, the invention relates to a control device for such a sensor device, an automation system having at least one sensor device and at least one control device and a corresponding method.

Description

Technical Field

[0001] This invention relates to a sensor device comprising: a sensor, particularly a switch-type sensor, such as, but not limited to, an incremental rotary encoder; and a signal interface for transmitting signals according to two communication standards. The invention also relates to a control device for such a sensor device, an automation system having at least one sensor device and at least one control device, and a corresponding method. Background Technology

[0002] In industrial and scientific fields, sensors are used to measure a variety of physical variables. At a primary functional level, these sensors output their measurements to a higher-level system in the form of standardized digital signals, such as time series of voltage levels.

[0003] For purposes such as sensor diagnostics, maintenance, parameterization, firmware upgrades, or other similar processes, it may also be necessary for the sensor to be able, at least temporarily, as a secondary function, to output other data, in the form of standardized digital signals, such as time series of voltage levels, to or receive from a higher-level system.

[0004] The communication standards used in industrial and scientific fields each have their strengths and weaknesses. Furthermore, some communication standards are incompatible with each other. Summary of the Invention

[0005] Therefore, the present invention is based on the objective of providing a possibility that allows for the selection of ideal communication standards for the primary and secondary functions mentioned earlier, even if the communication standards are not directly compatible with each other, with low power consumption and in a way that saves costs, materials and / or space.

[0006] According to the present invention, the purpose of achieving the aforementioned sensor device is as follows: a sensor device according to an embodiment of the present invention is designed.

[0007] The term “signal interface” here refers to an I / O interface, while the term “electrical logic level” here refers to Hi-Lo voltage levels, as is commonly used in digital or signal technologies.

[0008] This invention is advantageous in one respect because the switchability of the sensor device enables two separate operating states, namely a first operating state and a second operating state, allowing the sensor device to perform, for example, the primary and secondary functions mentioned earlier. In this case, apart from the switching process for each operating state described immediately, the first or second communication standard can be used separately from other communication standards without compatibility issues.

[0009] The sensor device is designed to identify switching signals, for example, from a higher-level control device, based on voltage, even if the voltage does not correspond to the first communication standard. This allows the sensor device to detect the switching signal while it is in its first operating state. This will be further explained in the following description.

[0010] In general, the solution according to the invention provides the possibility of transmitting signals via the same signal interface according to two communication standards that are not directly compatible with each other. This results in cost, material, and / or space savings for sensor devices and incurs only a small amount of power consumption, because it eliminates the need to additionally provide unnecessary auxiliary interfaces on the sensor device.

[0011] Of course, the solution according to the invention is not limited to sensor devices with only one signal interface, but can also be applied to sensor devices that have at least one additional interface in addition to the signal interface. However, in this case, the at least one additional interface is used for other functions or is not provided for implementing only the secondary functions mentioned at the beginning, and is not used for the primary functions mentioned at the beginning here either.

[0012] The solution according to the invention can be further improved through different design schemes, each advantageous in itself and arbitrarily combinable with each other. These design forms and their associated advantages are discussed below. The advantages described with respect to sensor devices, control devices, and automation systems also apply to the method according to the invention, and vice versa.

[0013] According to a first design of the sensor device according to the invention, the first communication standard can be a communication standard with a low electrical logic level to facilitate high-frequency signal transmission. In particular, the electrical logic level of the first combined standard can be lower than the threshold of the second communication standard. For example, the electrical logic level of the first communication standard can have a value between 0V and 5V + / - 0.4V or between 0V and 3.3V + / - 0.4V. In particular, the first communication standard can be the EIA-422 specification. This specification, due to its relatively low electrical logic level, is suitable for high-frequency signal transmission and thus extends the applicability of the sensor device according to the invention to application areas with high-frequency signal transmission requirements.

[0014] The invention outputs high-frequency measurements and is advantageously suited for applications such as rotary encoders that detect high-speed and / or rapidly variable angular positions. Accordingly, the sensor can be a rotary encoder. Furthermore, the sensor can be an incremental encoder, particularly an incremental rotary encoder. Alternatively, the sensor can also be an absolute encoder.

[0015] The sensor configured as a rotary encoder can be a digital rotary encoder or an analog rotary encoder, and its logic levels are represented by periodic sine and / or cosine functions. In the first operating state, the signal interface can be configured to output signals for rail A, rail B, rail U, rail V, rail W, or zero pulse.

[0016] To enable the transmission of corresponding high-frequency signals, as already mentioned, the following communication standards are suitable for primary functions, using relatively low voltage levels. For secondary functions where the transmission of high-frequency signals is not permitted, communication standards with relatively high voltage levels can be used.

[0017] Accordingly, the second communication standard can be any electrical logic level whose threshold is greater than that of the first communication standard. For example, the threshold of the second communication standard can be 8V. In particular, the second communication standard can be the IEC 61131-9 specification, which is also known by the brand name "IO-Link" or the name "SDCI (Single Point Digital Communication Interface for Small Sensors and Actuators)". In the following text, the term "IO-Link standard" should refer to the IEC 61131-9 specification. The IO-Link standard is a widely used communication standard, and its application allows the sensor devices according to the present invention to be used in a wide range of industrial and scientific fields.

[0018] According to the IO-Link standard, the switching signal can be a so-called "Master Wake-up." Master Wake-up here refers to the following switching command, which is sent from the higher-level communication user (e.g., a control device) to the lower-level communication user (e.g., a sensor) whenever there is a need for communication according to the IO-Link standard (e.g., diagnostics, maintenance, parameterization, firmware upgrades, etc.). The IO-Link standard specifies that Master Wake-up is issued as a current pulse at the time of the switching command, in relation to the sensor output signal, and this current pulse inverts the current sensor output signal. This means that if the lower-level communication user is currently outputting a Lo level at its interface, the higher-level communication user will force a Hi level at its interface as Master Wake-up, and vice versa.

[0019] As long as this reversal is ensured, lower-level communication users can identify master station wake-up by measuring the short-circuit current flowing at the interface. A short-circuit current always flows if the Hi level on the sensor side encounters the Lo level on the control device side, or vice versa.

[0020] When distinguishing between a lower-level communication user's current output Hi level and Lo level, the upper-level communication user applies an 8V threshold according to the IO-Link standard. This specifically means that all voltage levels below 8V are considered Lo levels.

[0021] This results in limitations on the ability to detect short-circuit current measurements, and consequently, incompatibility between the IO-Link standard and all communication standards with logic levels below the 8V threshold. In particular, the IO-Link standard is not easily compatible with the EIA-422 specification, because according to EIA-422, Hi level (=5V) and Lo level (=0V) are both treated as Lo level by the upstream communication user, especially since they are both below the 8V threshold of the IO-Link standard.

[0022] If, during the master station wake-up process, the Hi level on the sensor side encounters the Hi level on the control device side, as cannot be excluded under the combination of the EIA-422 specification and the IO-Link standard, there is no short-circuit current flow, making it possible to fail to correctly identify master station wake-up using measurements of the short-circuit current. This risk is advantageously eliminated by the solution according to the invention, because the sensor device is constructed to identify the switching signal not primarily based on the short-circuit current, but rather on the voltage applied to the sensor device.

[0023] According to another feasible embodiment, the sensor device can be configured to identify a switching signal based on a voltage applied to the signal interface. In particular, the sensor device can be configured to identify the switching signal based on a measurement of the voltage applied to the signal interface. Voltage measurement is a readily implementable method for identifying a switching signal based on a voltage applied to the signal interface.

[0024] Of course, for redundancy reasons, the sensor device is also configured to measure the short-circuit current in the sensor device in addition to measuring the voltage applied to the signal interface.

[0025] According to another feasible embodiment, the sensor device can include a line driver device for amplifying the sensor output signal. This signal amplification produces better transmission quality for the sensor output signal.

[0026] Furthermore, the sensor device can include a power supply device for feeding a power supply voltage to the line driver device. Optionally, the power supply device can be configured to set the power supply voltage according to the operating state. The power supply device thus allows for compliance with specifications regarding the power supply voltage in a first communication standard and a second communication standard. For example, through the power supply device, the power supply voltage in a first operating state can be adapted to the logic level of the first communication standard and / or the power supply voltage in a second operating state can be adapted to the logic level of the second communication standard.

[0027] The sensor device may include a voltage converter, preferably a DC-DC converter, which converts the supply voltage of a first operating state to the supply voltage of a second operating state upon receiving a switching signal. The voltage converter may be integrated into the circuitry of the line driver device or may exist as external circuitry. Alternatively, the voltage converter may be part of the power supply equipment.

[0028] Alternatively, the voltage converter can be configured to set the supply voltage according to the operating state.

[0029] According to the present invention, the sensor device includes a monitoring unit for monitoring the voltage applied to the sensor device. Preferably, the monitoring unit is configured as a voltmeter or voltage comparator that compares the supply voltage of the power supply device with the voltage applied to the signal interface. This comparison can be performed selectively continuously or periodically. According to the present invention, the monitoring unit is configured to identify a switching signal once the voltage applied to the signal interface exceeds the supply voltage for a predefined time period. The value of the predefined time period can, for example, be derived from a second communication standard and stored in the monitoring unit in a non-volatile manner.

[0030] Because in the first operating state, the supply voltage level according to the first communication standard represents the theoretical maximum voltage achievable at the signal interface on the sensor side, a voltage applied to the signal interface exceeding the supply voltage is an explicit indication that an electrical signal not corresponding to the first communication standard is arriving at the signal interface from the outside. In particular, exceeding is an indication of receiving a switching signal, as this is the only electrical signal not corresponding to the first communication standard expected in the first operating state of the sensor device. For example, exceeding can be understood as an indication for a higher-level control device to force a Hi level as a master station wake-up signal.

[0031] Alternatively, the monitoring unit can be configured to compare the voltage applied to the interface with a predefined, constant reference value. This reference value can correspond to a guide value for the supply voltage, derived from a first communication standard and stored non-volatilely in the monitoring unit.

[0032] The monitoring unit can be configured such that, upon recognizing a switching signal, the monitoring unit operates a switching element of the sensor device or induces operation of the switching element via the sensor device's microprocessor and / or microcontroller, thereby transitioning from a first operating state to a second operating state. In particular, the line driver device can switch to high impedance in the second operating state. This ensures that the internal signal flow of the sensor device is adapted to the second operating state.

[0033] Depending on the space-saving implementation, the monitoring unit can be integrated into the circuitry of the line driver device. In particular, the line driver device can have an application-specific integrated circuit that includes the monitoring unit.

[0034] Alternatively, the monitoring unit can exist as an external circuit, making it feasible to retrofit an already constructed or installed sensor device with a monitoring unit.

[0035] Optionally, the monitoring unit may include a filter component or filter function with a predefined time constant, which filters out or suppresses transient overvoltage peaks common during proper switching operation of switching sensors. The predefined time constant should not exceed the predefined time period mentioned above. Furthermore, the time period should be corrected for the time constant.

[0036] According to another embodiment, the sensor device can include a diode, preferably a Schottky diode, as an overvoltage protection device, disposed between the signal interface and the voltage converter. Specifically, the diode can point towards the signal interface in the cutoff direction and towards the voltage converter in the conduction direction. Therefore, the diode reliably protects the sensor device from overvoltages that may be caused by signal switching. The use of a Schottky diode is particularly advantageous due to its fast response capability and low forward voltage.

[0037] As an alternative to installing overvoltage protection devices, the components of the sensor device can be configured to have the corresponding electrical load capacity, allowing for the selective omission of overvoltage protection devices.

[0038] To enable bidirectional communication in the second operating state, the sensor device can be configured to output a communication signal with a logic level according to a second communication standard via a signal interface, also in the second operating state. Therefore, for example, the switching signal can be confirmed or relevant data can be transmitted to a higher-level control device for sensor diagnostic purposes. During the duration of this output, the line driver device can temporarily switch to low impedance.

[0039] Alternatively, the signal interface can also operate as a pure input interface in the second operating state. Furthermore, in the first operating state, the signal interface can operate as a pure output interface, except for receiving switching signals.

[0040] The initial objective can also be achieved through the control device according to an embodiment of the present invention.

[0041] Here, the term "communication interface" also refers to the I / O interface commonly used in digital or signal technologies.

[0042] Based on the operating mode and advantages already described for the sensor device, the control device according to the invention can advantageously realize the recording of sensor output signals at the sensor device via the same communication interface, as well as the arrangement and execution of diagnostics, maintenance, parameterization, firmware upgrades, etc., as needed, thereby saving costs, materials and / or space.

[0043] Depending on the application, the sensor output signal can be processed directly in the control device and / or forwarded for processing purposes to a processing device located above the control device in the automation system. Processing here can include evaluating and / or storing the sensor output signal.

[0044] According to a feasible implementation, the control device can be configured to output a switching signal within a predefined output time, wherein the value of the predefined output time originates from a second communication standard and corresponds to the value of the predefined time period mentioned above. Furthermore, the control device can be configured to wait for a predefined waiting time after outputting the switching signal and before outputting a communication signal, wherein the value of the predefined waiting time can originate from the second communication standard. Alternatively or additionally, the control device can be configured to wait for the output communication signal after outputting the switching signal until the switching signal is acknowledged by the sensor device. Furthermore, the control device can be configured to output a new switching signal if the previous switching signal is not acknowledged within a predefined acknowledgment time. In this way, it is ensured that the switching and communication signals output by the control device can be correctly received by the sensor device.

[0045] Preferably, the control device can also be configured to receive communication signals from the sensor device having electrical logic rules according to a second communication standard.

[0046] The control device according to the invention is capable of using the same specifications for the first communication standard and / or the second communication standard as described with respect to the sensor device according to the invention. Accordingly, the switching signal that can be received by the sensor device can be the same as the switching signal that can be output by the control device.

[0047] According to another feasible embodiment, at least one data line extending from the sensor device can be connected to the communication interface of the control device. Optionally, multiple data lines extending from the sensor device can be connected to the control device. Correspondingly, at least one data line leading to the control device can be connected to the signal interface of the sensor device. Optionally, multiple data lines leading to the control device can be connected to the sensor device.

[0048] An automation system for technical facilities includes at least one sensor device according to the above embodiment and at least one control device according to the above embodiment, which also achieves the initial objective, wherein the signal interface of the at least one sensor device is connected to the communication interface of the at least one control device. In particular, the signal and communication interfaces can be connected via one or more data lines.

[0049] By virtue of the aforementioned advantages of the sensor device and control device according to the invention, the automation system according to the invention can advantageously save costs, materials and / or space, especially when connecting related interfaces, such as data cables, because signal transmission of the sensor device in both the first and second operating states can be carried out via the same interface, especially the same data cable, according to the invention.

[0050] The initial objective can also be achieved through the method according to embodiments of the present invention.

[0051] This method can be used in sensor devices according to the invention or in automated systems according to the invention, bringing the advantages already mentioned, and thus helping to save costs, materials and / or space.

[0052] This method can be executed, in particular, entirely or at least partially, by a microprocessor or microcontroller of the sensor device. Alternatively or additionally, the method can also be a computer-implemented method. Therefore, the invention also relates to a computer program comprising commands that cause execution of the method according to the invention. Furthermore, the invention relates to a computer-readable storage medium on which such a computer program is stored.

[0053] Any references to specifications and standards (such as EIA specifications, IEC specifications, etc.) in this application refer to the version of the relevant specification or standard that was applicable at the time of its development. Attached Figure Description

[0054] The invention is described in detail below with reference to the accompanying drawings. The feature combinations exemplarily shown in the illustrated embodiments can be supplemented by additional features to meet the specific application requirements of the sensor device, control device, and / or automation system according to the invention, based on the above embodiments. Furthermore, also according to the above embodiments, if the effect of an individual feature is not significant in a particular application, that feature can be omitted in the described embodiments. In the drawings, the same reference numerals are consistently used for elements with the same function and / or the same structure.

[0055] In the attached diagram:

[0056] Figure 1A schematic diagram of the sensor device according to the present invention is shown;

[0057] Figure 2 A schematic diagram of an automation system according to the invention, having a sensor device according to the invention and a control device according to the invention, is shown; and

[0058] Figure 3 A schematic diagram showing time graphs of different associated process variables before and after receiving a switching signal in the sensor device according to the invention. Detailed Implementation

[0059] The following is for reference. Figure 1 or Figure 2 The sensor device 1 according to the invention, the control device 2 according to the invention, and the automation system 4 according to the invention are described below. Reference is then made to... Figure 3 The switching process of the sensor device 1 according to the present invention is described.

[0060] Figure 1 A simplified schematic diagram of the sensor device 1 according to the present invention is shown. The sensor device 1 can be confined by its own housing 6 and / or mounted in the housing of a system unit (not shown) located above the sensor device 1.

[0061] In the illustrated embodiment, the sensor device 1 includes: a sensor 8, particularly a switch-type sensor 10, such as, but not limited to, an incremental rotary encoder 12; and a signal interface 14, particularly an I / O interface 16, for transmitting signals.

[0062] Sensor 8 is configured to measure physical variables 20 occurring in region 18 and output said physical variables as measurement signals 22 in the form of electrical logic level 24 (see also...). Figure 3 In the illustrated embodiment, sensor 8 outputs its measurement signal 22 to line driver device 26 of sensor device 1, which amplifies the measurement signal 22 and outputs it as sensor output signal 28 to signal interface 14.

[0063] Sensor device 1 is configured such that, in the first operating state 30 (see...) Figure 3 The sensor output signal 28, having an electrical logic level 34 according to the first communication standard, is output via signal interface 14 (see [link]). Figure 3 To this end, sensor device 1 includes a power supply device 36 for feeding an regulated supply voltage 38 to line driver device 26, the supply voltage being adapted to the logic level 34 of a first communication standard in a first operating state. In the exemplary embodiment shown, the power supply device 36 supplies power to line driver device 26 via voltage converter 40 of sensor device 1, the function of which is described in detail below.

[0064] Furthermore, sensor device 1 is configured to receive an electrical switching signal 42 that does not correspond to the first communication standard (see [link]). Figure 1 The sensor device 1 is configured to switch to the second operating state 32 upon receiving the switching signal 42 (see [link]). Figure 3 Furthermore, the sensor device 1 is configured to receive a communication signal 44 having a logic level according to a second communication standard via the signal interface 14 in the second operating state 32, wherein the logic level 34 of the first communication standard is different from the logic level of the second communication standard.

[0065] The switching signal 42 is identified based on a voltage 46 applied to the sensor device 1, which does not correspond to the logic level 34 of the first communication standard. In particular, the sensor device 1 can be configured to identify the switching signal 42 based on a voltage 48 applied to the signal interface 14. To this end, the sensor device 1 can be configured to identify the switching signal 42 based on a measurement of the voltage 48 applied to the signal interface 14.

[0066] In the exemplary embodiment shown, the transmitting device 1 includes a monitoring unit 50 for monitoring the voltage 46 applied to the sensor device 1. The monitoring unit 50 can be configured as a voltage comparator 52 and / or a voltmeter, and continuously compares the supply voltage 38 at the output of the voltage converter 40 with the voltage 48 applied to the signal interface 14. This comparison can also be performed periodically.

[0067] The first communication standard can be the EIA-422 specification. The second communication standard can be the IEC 61131-9 specification. The switching signal 42 can correspondingly be the so-called "master wake-up" according to the IEC 61131-9 specification. Specifically, the switching signal 42 can be a voltage 54 forced by the control device 2, as it is in... Figure 3 As indicated by the lightning bolt symbol. The forced voltage 54 here does not correspond to logic level 34 in the EIA-422 specification and is in particular higher than logic level 34 in the EIA-422 specification.

[0068] Therefore, the comparison described above in the monitoring unit 50 can identify when the voltage 48 applied to the signal interface 14 exceeds the supply voltage 38. This exceeding does not correspond to an indication that an electrical signal from the first communication standard has arrived at the signal interface 14 from the outside, because the level 56 of the supply voltage 38 (see...) Figure 3) is the theoretical maximum voltage achievable on the sensor side at signal interface 14. In particular, exceeding is an indication of receiving the switching signal 42, as this is the only electrical signal not corresponding to the first communication standard expected in the first operating state 30 of the sensor device. Therefore, in the exemplary embodiment shown, exceeding can be understood as an indication of forcing the master station to wake up via the superior control device 2 as voltage 54.

[0069] See below for reference Figure 3 As detailed above, the monitoring unit 50 can be configured to respond to a voltage 48 applied to the signal interface 14 within a predefined time period t. WU The internal voltage exceeds the supply voltage by 38 (see Figure 3 The switching signal 42 was identified. The predefined time period t... WU The value here can, for example, be derived from a second communication standard and stored in the monitoring unit 50 in a non-volatile manner.

[0070] Optionally, the monitoring unit can include a predefined time constant t. SCFILT The filter components or filter functions that filter out transient overvoltage peaks common during the proper switching operation of switching sensors 58 (see...). Figure 3 This is in Figure 3 As shown in the image.

[0071] Time constant t SCFILT The selected option here is: no more than the predefined time period t mentioned above. WU Furthermore, the monitoring unit 50 can be configured to operate with a time constant t. SCFILT The value is used to correct the predefined time period t. WU Time detection. Therefore, the time constant t... SCFILT It can also be stored in the monitoring unit 50 in a non-volatile manner.

[0072] For redundancy, the sensor device 1, and especially the monitoring unit 50, can be additionally configured to measure the short-circuit current 60 in the sensor device 1, in addition to measuring the voltage 48 applied to the signal interface 14. For example, the monitoring unit 50 can measure the short-circuit current 60 at the line driver device 26 or at least record the presence of the short-circuit current 60.

[0073] The monitoring unit 50 can also be configured to output message 62 to the microprocessor 64 or microcontroller 66 of the sensor device 1 after the switching signal 42 is detected. Therefore, a transition from the first operating state 30 to the second operating state 32 can be arranged. In particular, in the second operating state 32, the line driver device 26 can be switched to high impedance via command 68 from the microprocessor 64 or microcontroller 66.

[0074] The voltage converter 40 is preferably a DC-DC converter 70, which is configured to adapt the supply voltage in the second operating state 32 to the logic level of the second communication standard. Specifically, this can be performed after the switching signal 42 is detected and according to the command 72 of the microprocessor 64 or microcontroller 66, such that the supply voltage 38 of the first operating state 30 is converted to the supply voltage 32 of the second operating state.

[0075] The voltage converter 40 and / or monitoring unit 50 can be integrated into the circuitry 74 or circuit board of the line driver device 26, such as in Figure 1 As shown in the diagram. Alternatively, the voltage converter 40 and / or monitoring unit 50 can be separate circuits.

[0076] exist Figure 1 In the exemplary embodiment shown, the sensor device 1 includes an overvoltage protection device 76 disposed between the signal interface 14 and the power supply device 36. The overvoltage protection device 76 can be, for example, a diode 78, preferably a Schottky diode 80, with its cut-off direction pointing towards the signal interface 14 and its conduction direction pointing towards the voltage converter 40 or the power supply device 36. Therefore, the sensor device 1 can be protected from overvoltage caused by the electrical switching signal 42.

[0077] The sensor device 1 can also be configured to output a communication signal 44 with a logic level according to a second communication standard via the signal interface 14 during the second operating state 32. For the duration of this output, the line driver device 26 can temporarily switch to low impedance via command 68.

[0078] At least one data line 82 leading to the control device 2 can be connected to the signal interface 14 of the sensor device 1. In addition to the signal interface 14, the sensor device 1 may also have at least one other interface 84, so that multiple data lines 82, 86 leading to the control device 2 can be connected to the sensor device 1.

[0079] exist Figure 2 In the exemplary embodiment shown, the control device 2 has a communication interface 88, to which a data line 82 extending from the sensor device 1 can be connected. In addition to the communication interface 88, the control device 2 may also have another interface 90, allowing the data line 86 extending from the sensor device 1 to also be connected to the control device 2.

[0080] In the illustrated embodiment, the control device 2 is accordingly configured to receive a sensor output signal 28 having an electrical logic level 34 according to a first communication standard via a communication interface 88. Depending on the application, the control device 2 can internally process the received sensor output signal 28 and / or, for processing purposes, forward it to a processing device (not shown) located above the control device 2 in the automation system 4. For this purpose, a corresponding interface 92 can also be provided on the control device 2.

[0081] Furthermore, the control device 2 is configured to output an electrical switching signal 42 that does not correspond to the first communication standard, and to output a communication signal 44 having a logic level according to the second communication standard after outputting the switching signal 42.

[0082] In the illustrated embodiment, the control device 2 is configured to output a switching signal 42 within a predefined output time period, wherein the value of the predefined output time period originates from a second communication standard and is compatible with the predefined time period t mentioned above. WU The value matches.

[0083] Optionally, the control device 2 can also be configured to receive a communication signal 44 having an electrical logic level according to a second communication standard from the sensor device 1. Accordingly, the control device 2 can be configured to wait for the output of the communication signal 44 after outputting the switching signal 42, until the switching signal 42 is acknowledged by the sensor device 1. Furthermore, the control device 2 can be configured to output a new switching signal if the previous switching signal 42 is not acknowledged within a predefined acknowledgment time.

[0084] As in Figure 2 As shown, the automation system 4 includes at least one sensor device 1 and at least one control device 2, wherein the signal interface 14 of the at least one sensor device 1 is connected to the communication interface 88 of the at least one control device 2. In the illustrated embodiment, the signal interface 14 and the communication interface 88 are connected via a data line 82. Signal transmission in the first operating state 30 and the second operating state 32 is performed via the same data line 82.

[0085] The following is for reference. Figure 3 The time graph illustrates the method for switching the operating state of sensor device 1 according to the present invention. A brief introduction to the shown change curves follows:

[0086] The horizontal axis shows the time variation curves from left to right.

[0087] The signal change curve 101 at the top of the time graph represents the voltage level 24 of the binary measurement signal 22 in sensor 8.

[0088] The second signal variation curve 102 shows the voltage level 34 of the sensor output signal 28 amplified in the line driver device 26. This also corresponds to the voltage 48 applied to the signal interface 14.

[0089] The third signal change curve 103 shows the time change curve of the supply voltage 38.

[0090] The fourth signal change curve 104 shows the unfiltered voltage comparison of the monitoring unit 50. The Hi level here indicates that there is a voltage exceeding the supply voltage of 38.

[0091] The penultimate signal change curve 105 shows the filtered voltage comparison of monitoring unit 50. The Hi level here also indicates that there is an excess of the supply voltage 38.

[0092] The voltage level of message 62 at microprocessor 64 or microcontroller 66 is shown in the signal change curve 106 at the bottom. The Hi level here indicates that the switching signal 42 has been detected.

[0093] The lightning bolt icon in the second signal change curve 102 marks the first appearance of the switching signal 42. Sensor device 1 is in the first operating state 30 at this point, and the signal interface 14 of sensor device 1 is used as a pure output interface until this time. The measurement signal 22 is output by sensor 8, for example, as a square wave voltage 94, and is amplified in the line driver device 26 to become the sensor output signal 28.

[0094] Except for the duration not exceeding the time constant t SCFILT Apart from the brief overvoltage peak 58, no voltage exceeding the supply voltage 38 occurred. Although the overvoltage peak 58 caused a brief offset 96 in the unfiltered voltage comparison, it was suppressed by the filter function of the monitoring unit 50 and therefore not considered by the monitoring unit 50 (see [link to relevant documentation]). Figure 3 The penultimate signal change curve in (105).

[0095] Whenever switching signal 42 is present, it affects the voltage 48 applied to signal interface 14 and, in particular, causes it to rise continuously (see [link]). Figure 3 The second signal change curve (102) in the figure.

[0096] With the assistance of the overvoltage protection device 76, in the exemplary embodiment shown, the supply voltage 38 also rises with the same slope and a slight delay (see [link to example]). Figure 3 (See the third signal change curve 103). Due to a slight delay, the voltage 48 applied to the signal interface 14 now exceeds the supply voltage 38.

[0097] Once the duration of this excess of the supply voltage 38 exceeds the time constant t...SCFILT This exceedance is recorded by the monitoring unit at 50 (see in...). Figure 3 The fifth signal change curve (105) in the figure.

[0098] The supply voltage of 38 exceeds a predefined time period t. WU Subtract the time constant t SCFILT Then, the monitoring unit 50 outputs message 62 as a Hi level to the microprocessor 64 or the microcontroller 66.

[0099] Subsequently, the system switches from the first operating state 30 to the second operating state 32. The sensor device 1 can then begin receiving and / or outputting communication signals 44.

Claims

1. A sensor device (1) having a sensor (8) and a signal interface (14). The sensor device (1) is configured to output a sensor output signal (28) of the sensor (8) having an electrical logic level (34) according to a first communication standard via the signal interface (14) in a first operating state (30), and to receive an electrical switching signal (42) that does not correspond to the first communication standard. The sensor device (1) is configured to switch to a second operating state (32) upon receiving the switching signal (42). The sensor device (1) is configured to receive a communication signal (44) having a logic level according to a second communication standard via the signal interface (14) in a second operating state (32). The logic level (34) of the first communication standard is different from the logic level of the second communication standard. Its features are, The sensor device (1) includes a monitoring unit (50) for monitoring the voltages (46, 48) applied to the sensor device (1), and the monitoring unit (50) is configured to monitor the voltages (46, 48) applied to the signal interface (14) within a predetermined time period (t). WU If the voltage exceeds the supply voltage (38), the switching signal (42) is identified, wherein the voltage (46, 48) does not correspond to the logic level (34) of the first communication standard.

2. The sensor device (1) according to claim 1, wherein the sensor device (1) includes a line driver device (26) for amplifying the sensor output signal (28) and a voltage converter (40) for feeding the supply voltage (38) to the line driver device (26).

3. The sensor device (1) according to claim 2, wherein the monitoring unit (50) is integrated into the circuit (74) of the line driver device (26).

4. The sensor device (1) according to claim 2 or 3, wherein the voltage converter (40) is configured to set the power supply voltage (38) according to the operating state (30, 32).

5. The sensor device (1) according to claim 2 or 3, wherein the sensor device (1) as an overvoltage protection device (76) includes a diode (78) disposed between the signal interface (14) and the voltage converter (40).

6. The sensor device (1) according to claim 5, wherein the diode (78) is configured as a Schottky diode (80) with its cut-off direction pointing to the signal interface (14) and its conduction direction pointing to the voltage converter (40).

7. The sensor device (1) according to any one of claims 1 to 3, wherein the sensor (8) is an incremental encoder and / or a rotary encoder.

8. The sensor device (1) according to any one of claims 1 to 3, wherein the electrical logic level of the first communication standard has a value between 0V and 5V+ / -0.4V or between 0V and 3.3V+ / -0.4V.

9. The sensor device (1) according to any one of claims 1 to 3, wherein the electrical logic level of the second communication standard has the form of an IO-Link signal.

10. The sensor device (1) according to any one of claims 1 to 3, wherein the electrical logic level of the second communication standard has a threshold of 8V, and all signals below the threshold are considered to be at the Lo level.

11. A control device (2) for a sensor device (1), wherein the control device (2) has a communication interface (88), wherein the control device (2) is configured to receive a sensor output signal (28) having an electrical logic level (34) according to a first communication standard via the communication interface (88), characterized in that, The control device (2) is further configured to output an electrical switching signal (42) that does not correspond to the first communication standard to the sensor device (1) via the communication interface (88), and after outputting the switching signal (42), output a communication signal (44) having an electrical logic level according to the second communication standard to the sensor device (1), wherein the logic level (34) of the first communication standard is different from the logic level of the second communication standard.

12. The control device (2) according to claim 11, wherein the electrical logic level of the first communication standard has a value between 0V and 5V+ / -0.4V or between 0V and 3.3V+ / -0.4V.

13. The control device (2) according to claim 11, wherein the electrical logic level of the second communication standard has the form of an IO-Link signal.

14. The control device (2) according to claim 11, wherein the electrical logic level of the second communication standard has a threshold of 8V, and all signals below this threshold are considered to be at the Lo level.

15. An automation system (4) for a technical facility, the automation system comprising at least one sensor device (1) according to any one of claims 1 to 10 and at least one control device (2) according to any one of claims 11 to 14, wherein a signal interface (14) of at least one of the sensor devices (1) is connected to a communication interface (88) of at least one of the control devices (2).

16. A method for switching the operating states (30, 32) of a sensor device (1) according to a switching signal (42), at least from a first operating state (30) to a second operating state (32), wherein in the first operating state the sensor device (1) outputs a sensor output signal (28) having an electrical logic level (34) according to a first communication standard, and in the second operating state the sensor device (1) receives a communication signal (44) having an electrical logic level according to a second communication standard, wherein the logic level (34) of the first communication standard is different from the logic level of the second communication standard, characterized in that, The monitoring unit (50) monitors the voltages (46, 48) applied to the signal interface (14) of the sensor device (1) and automatically switches from the first operating state (30) to the second operating state (32), wherein once the voltages (46, 48) applied to the signal interface (14) have been within a predetermined time period (t... WU If the voltage exceeds the supply voltage (38), the switching signal (42) is identified, wherein the voltage (46, 48) does not correspond to the logic level (34) of the first communication standard.

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