MANUALLY RESET SWITCHING DEVICE

Description

[0001] The invention relates to a manually resettable switching device which can be used, for example, in process control systems in the field of automation technology.

[0002] Electronic devices used, for example, in process control systems must be capable of being reset to their normal operating state by acknowledgment after they have been shut down due to a detected error. Acknowledgment or resetting of an electronic device after an error has occurred can be achieved, for example, via a switch or button implemented on the device, via a separate reset input, or, if the electronic device is connected to a bus system, via a software command generated, for example, by a higher-level controller (e.g., a PLC). A manually resettable switching device is known, for example, from document US 2016 / 042899 A1.This manually resettable switching device can be controlled into a first or a second operating state and has a current path with an input terminal to which an input voltage can be applied and with an output terminal, a manually pluggable relay having a coil, and a switching element which is connected into the current path when the relay is plugged in, as well as a control and evaluation device which is designed to detect faulty operation of the switching device.

[0003] The invention is based on the object of creating a manually resettable switching device that can be quickly and easily reset to normal operation after a fault-related shutdown, even if the switching device does not have a separate reset input or reset switch. Particularly in an electronic device housed in a very narrow housing, for example, a narrow terminal block housing, there is often no space for a reset switch or a free terminal point that could be used as a reset input.

[0004] A core concept of the invention can be seen in equipping a switching device with a manual reset mechanism, which can be implemented, for example, by means of a removable and reinsertable relay and a circuit. The circuit serves, in particular, to monitor the removal and reinsertion of the relay and, after a fault-related shutdown, to reset the switching device to a normal operating state simply by removing and reinserting the relay. The relay performs a dual function: Firstly, it acts as a switching device for opening and closing at least one current path of the switching device, and secondly, it forms part of the reset mechanism.

[0005] The above-mentioned technical problem is solved by the features of claim 1. Advantageous further developments and embodiments are the subject of the subclaims.

[0006] The invention is explained in more detail below using an exemplary embodiment in conjunction with the accompanying drawings, in which: Figure 1 shows an exemplary manually resettable switching device, and Figure 2 shows a housing, in particular a mounting rail housing, in which the switching device is at least partially arranged.

[0007] In the Figure 1An exemplary manually resettable switching device 10 is shown, which can be designed as a single-phase or multi-phase device in order to connect an electrical load (not shown) that can be connected on the output side to or disconnect it from a supply energy that can be applied on the input side. The switching device 10, which is shown only as an example and explained below, is designed as a single-phase switching device that can be controlled, for example, into a first or second operating state. The first operating state can represent normal, fault-free operation, while the second operating state can represent, for example, the shutdown mode triggered as a result of a fault.

[0008] The switching device 10 has, for example, a ground terminal 22 and an input terminal 20, to which an input voltage can be applied. According to the exemplary embodiment, a power supply device 5 can be connected to the input terminal 20 and the ground terminal 22. For example, the power supply device 5 can provide a DC voltage of 24 V at the input terminal 20. The input terminal 20 can be connected via a current path 110 to an output terminal 21, which can function as a fused output terminal. If the switching device 10 were designed to be multi-phase, multiple input terminals, multiple current paths, and multiple output terminals would be implemented.

[0009] The switching device 10 may further include a manually pluggable relay 40, which has a coil 42 and a switching element 41. The switching element 41 is preferably implemented as a normally open contact. However, it could also be designed as a changeover switch. As shown in Figure 2As can be seen, the exemplary relay 40 has two coil terminals 43 and 44 and two switching element terminals 45 and 46. When the relay 40 is plugged in, the switching element 41 is connected into the current path 110. For this purpose, two connection contacts 62 and 63 are provided in the current path 110, which are electrically connected to the switching element terminals 45 and 46 of the relay 40 when the relay 40 is plugged in. In addition, the switching device 10 has two further connection contacts 60 and 61, which are electrically connected to the two coil terminals 43 and 44 of the relay coil 42 when the relay 40 is plugged in. The connection contact 60 is electrically connected to the input terminal 20. Consequently, when the relay 40 is plugged in, the exemplary DC voltage of 24V is also present at the coil terminal 43. The connection contacts 60 to 63 are also in Figure 2shown in connection with an exemplary housing 130 of the switching device 10. In the plugged-in state of the relay 40, the coil terminal 44 of the coil 42 can be connected to ground via the connection contact 61, for example via a first semiconductor switch 80 that can be controlled by a control and evaluation device 100. The ground is shown as ground terminal 22. The semiconductor switch 80 can be designed, for example, as a field-effect transistor or as a bipolar transistor. In the present example, the semiconductor switch 80 is an npn transistor having a base terminal 82, a collector terminal 81 electrically connected to the connection contact 61, and an emitter terminal 83 connected to the ground terminal 22. The base terminal 82 can be connected to an output 101 of the control and evaluation device 100 via a voltage divider, which, for example, has two electrical resistors 90 and 91 connected in series.For this purpose, the base terminal 82 can be electrically connected to the contact point connecting the two resistors 90 and 91.

[0010] The control and evaluation device 100 is designed, for example, to detect faulty operation of the switching device 10 and, in response thereto, to set the switching device 10 into the second operating state. To detect a fault, for example, a measuring device 50, which is designed in particular to measure a current through the current path 110, can be connected into the current path 110. The control and evaluation device 100 can be designed to detect faulty operation of the switching device 30 depending on a measured value received from the measuring device 50. Faulty operation can be detected by the control and evaluation device 100, for example, if the current flowing through the current path 110 exceeds a predetermined threshold current value known to the control and evaluation device 100.Furthermore, the manually resettable switching device 10 can have a detection device 70, which is preferably electrically connected to an input 102 of the control and evaluation device 100. The detection device 70 is designed to signal to the control and evaluation device 100 whether the relay 40 is plugged in or unplugged. The control and evaluation device 100 is further designed to... i) to detect whether the relay 40 has been pulled out after a detected faulty operation and has been plugged in again after a predetermined time has elapsed, and if so, ii) to set the switching device 10 to the first operating state, in particular to reset it.

[0011] The control and evaluation device 100 can monitor the time lapse with the aid of a timer 105, which can be an integral part of the control and evaluation device 100 or can be designed as a separate component which can be electrically connected to the control and evaluation device 100, as shown by way of example in Figure 1 is shown.

[0012] At this point, it should be noted that the control and evaluation device 100 can be a microcontroller. Furthermore, it should be noted that the detection device 70 can contain a voltage divider, which, for example, has two electrical resistors 71 and 72 connected in series. In this case, one terminal of the electrical resistor 71 can be electrically connected to the connection contact 61, while one terminal of the resistor 72 can be connected to the ground connection 22. The contact point connecting the two electrical resistors 71 and 72 to one another is, for example, electrically connected to the input 102 of the control and evaluation device 100. In the exemplary switching device 10, in this case, the voltage divider 70 is connected in parallel to the semiconductor switch 80 or in parallel to the emitter-collector path of the npn transistor.The power supply to the control and evaluation device 100 can be provided via an internal voltage converter 120, which can transform the DC voltage applied to the input terminal 20, for example, 24 V, into a lower DC voltage, for example, a DC voltage of 3.3 V, and supply it to the control and evaluation device 100. It should also be noted that an AC voltage can also be applied to the input terminal 20. In this case, the AC voltage is converted by the voltage converter 120 into a DC voltage of, for example, 3.3 V.

[0013] In particular, the control and evaluation device 100 is designed to deactivate the switching device 10 or to set it to the second operating state in response to a detected faulty operation. To this end, the control and evaluation device 10 can cause the relay 40 to be deactivated by means of the semiconductor switch 80 or the coil 42 to be de-energized. This measure can open the switching element 41, interrupt the current path 110, and thus separate the output terminal 21 from the input terminal 20, to which the supply voltage can be applied. To achieve this, the control and evaluation device 100 can set the output 101 to 0V, thereby controlling the transistor 80 into the blocking state.

[0014] In order to enable reliable separation of the output terminal 21 from the input terminal 20 in the event of a fault, a further semiconductor switch 30, which can be controlled by the control and evaluation device 100, can be connected in series with the switching element 41 of the relay 40 in the current path 110. The control and evaluation device 100 can be designed to also open the second semiconductor switch 30 in response to a detected faulty operation of the switching device 10. Preferably, the control and evaluation device 100 is designed to, for example, first electrically block or open the second semiconductor switch 30 in response to a detected faulty operation of the switching device 10 and then, for example after a predetermined time has elapsed, to switch off the relay 40 or open the switching element 41 of the relay 40.The second semiconductor switch 30 can in turn be implemented, for example, as a field-effect transistor or as a bipolar transistor.

[0015] In the normal, i.e., first, operating state of the switching device 10, the semiconductor switch 80 is closed, so that when the relay 40 is plugged in, current flows through the coil 42 and thus the switching element 41, which functions, for example, as a normally open contact, is closed. This can be achieved by the control and evaluation device 100 providing a voltage of, for example, 3.3 V at the input 101, which ensures that a sufficiently high control voltage is applied to the base terminal of the semiconductor switch 80, which is designed, for example, as an NPN transistor, via the voltage divider 90, 91.

[0016] The switching device 10 is preferably arranged at least partially in a housing 130. Figure 2shows a side view of the housing 130 in the open state. The current path 110, the control and evaluation device 100, and the detection device 70 are schematically shown within the housing 130. The housing 130 can be designed, for example, as a mounting rail housing, such as a terminal block housing, which can be mounted on a mounting rail. For this purpose, corresponding locking elements 134 can be provided on the underside of the housing 130. The overall width of the housing 130 is preferably very narrow, for example, less than or equal to 6 mm. The housing 130 can be a plastic housing.

[0017] The connection contacts 60-63 of the switching device 10 can be located on a side of the mounting rail housing 130 opposite the side with the locking elements. The connection contacts 60 to 63 can be designed as socket contacts, with which the coil connections 43, 44 and the switching element connections 45, 46 of the relay 40 are electrically connected in the plugged-in state. The coil connections and switching element connections are in this case designed as contact pins. The housing 130 can have a receiving area 135 on the housing side on which the connection contacts 60 to 63 are located, into which the relay 40 can be plugged. Furthermore, the example shown in Figure 2The mounting rail housing 130 shown may have a terminal 131 that is electrically connected to the input terminal 20 of the switching device or forms the input terminal 20. A further terminal 132 may be electrically connected to the output terminal 21 of the switching device 10 or form the output terminal 21. A further terminal 133 may form the ground terminal 22 of the switching device 10. A further terminal 136 may also function as a ground terminal. Figure 1 The power supply device 5 shown can be connected to the terminals 131 and 133, while an electrical or electronic load can be connected to the terminals 132 and 136.

[0018] The following describes the functionality of the Figure 1 The manually resettable switching device 10 shown as an example is explained in more detail.

[0019] First, it is assumed that the switching device 10 is operating in error-free mode. This means that the control and evaluation device 100 provides corresponding control signals for the semiconductor switches 30 and 80, which cause the semiconductor switches 30 and 80 to be closed or switched on, respectively. The switched-on semiconductor switch 80, in turn, causes current to flow through the coil 41 of the relay 40, and consequently, the switching element 41 of the relay 40 is also closed. In this way, the current path 110 between the input terminal 20 and the output terminal 21 is switched on. This corresponds to the first operating state of the switching device 10.

[0020] Let us now assume, by way of example, that the measuring device 50 has measured a current in the current path 110 that is greater than or equal to a predetermined threshold value. The measured current value is fed to the control and evaluation device 100, which detects faulty operation of the switching device 10 as a function of the measured current. In response to the detected faulty operation, the control and evaluation device 100 provides, for example with a time delay, corresponding control signals for the semiconductor switches 30 and 80 at its outputs 103 and 101. These control signals cause the semiconductor switch 30 to be opened or switched to the blocking state first, and then the semiconductor switch 80 to be controlled to the blocking or open state. For this purpose, a control voltage of 0V can be applied to each of the two outputs 101 and 103, for example.If the semiconductor switch 80 is switched off, the input voltage of, for example, 24 V present at the connection contact 60 or at the coil connection 43 also appears at the connection contact 61 or at the coil connection 44, whereupon the coil 42 is de-energized, i.e., switched off. In other words: The relay 40 drops out, and the switching element 41 also opens the current path 110. The switching device 10 is thus switched off or is in its second operating state. The second operating state is therefore characterized in particular by the fact that the output connection 21 is electrically isolated from the input connection 20.

[0021] The switching device 10 now awaits a manual reset, i.e., a reactivation and thus a resetting of the switching device 10 to its initial operating state. This can be achieved, for example, by the customer removing the relay 40 from the switching device 10 or the housing 130 and reinserting it after a predetermined period of time. This behavior can be monitored and recorded by the control and evaluation device 100 in conjunction with the detection device 70 and the timer 105. This is explained in more detail below using an example.

[0022] As already explained above, the control and evaluation device 100 is designed to ensure, in response to a detected fault, that the semiconductor switch 30, if present, is opened or switched to the blocking state, and subsequently the semiconductor switch 80 is opened or switched to the blocking state, so that the input voltage is also applied to the coil terminal 44. This state is detected by the detection device 70, which is formed, for example, by the voltage divider 71 and 72, and applied as a high level to the input 102 of the control and evaluation device 100. In order to reset the switching device 10, the control and evaluation device 100 now expects the relay 40 to be removed and, after the predetermined time has elapsed, to be reinserted.

[0023] If the customer now pulls the relay 40, the potential at the connection contact 61 drops to 0 V, which in turn is detected by the voltage divider or the detection device 70 and signaled as a low level at the input 102 of the control and evaluation device 100. In response to this level change at the input 102 of the control and evaluation device 100, the timer 105, which can also be an integral component of the control and evaluation device 100, is started, whereby the predetermined time now expires. After the predetermined time has elapsed, the control and evaluation device 100 expects a high level to be applied again at the input 102, which signals that the relay has been reinserted. It is now assumed that the customer has reinserted the relay 40 into the switching device 10 or the housing 130 after the predetermined time has elapsed.As a result, the voltage present at input terminal 20 is again present at connection contact 61. The level change from low to high at connection contact 61 is detected by detection device 70 and applied again as a high level to input 102 of control and evaluation device 100. In response to the level change at input 102 from low to high, control and evaluation device 100 provides corresponding control signals for semiconductor switches 30 and 80 at its outputs 103 and 101, which cause semiconductor switches 30 and 80 to be closed again or controlled into their conducting state. The conducting semiconductor 80 causes current to flow through coil 42 again, thereby causing switching element 41 to close current path 110 again.In other words, after the switching device 10 is reset to the first operating state, the current path 110 is closed again by means of the semiconductor switch 30 and the switching element 41 of the relay 40, thus electrically connecting the input terminal 20 to the output terminal 21. It should be noted that the semiconductor switch 30 is not required for proper operation of the switching device 10.

[0024] At least some of the exemplary aspects explained above are summarized below.

[0025] According to one exemplary aspect, a manually resettable switching device 10 is provided that can be controlled into a first or a second operating state. The switching device 10 can have the following features: a current path 110 with an input terminal 20, to which an input voltage can be applied, and with an output terminal 21, a manually pluggable relay 40 having a coil 42 and a switching element 41, which is connected to the current path 110 when the relay 40 is plugged in, a control and evaluation device 100, which is designed to detect faulty operation of the switching device 10 and, in response thereto, to set the switching device 10 into the second operating state, a detection device 70, which is electrically connected to the control and evaluation device 100 and is designed to signal to the control and evaluation device 100 whether the relay 40 is plugged in or pulled out, wherein the control and evaluation device 100 is further designed to i) detect whether the relay 40 has been pulled out after a detected faulty operation and has been plugged in again after a predetermined time has elapsed, and if so,ii) to set the switching device 10 into the first operating state.

[0026] Advantageously, the switching device can have a first semiconductor switch 80 that can be controlled by the control and evaluation device 100, wherein the control and evaluation device 100 is designed to de-energize the coil 42 of the relay 40 by means of the semiconductor switch 80 in response to a detected faulty operation.

[0027] Advantageously, the first semiconductor switch 80 is connected in parallel to the detection device 70, wherein the first semiconductor switch 80 and the detection device 70 can be connected in series with the coil 42 when the relay 40 is plugged in.

[0028] Advantageously, the detection device 70 may comprise a voltage divider which may, for example, contain two electrical resistors 71 and 72 connected in series.

[0029] Advantageously, the switching device can have a second semiconductor switch 30 which can be controlled by the control and evaluation device 100 and which is connected in series with the switching element 41 of the relay 40 in the current path 110, wherein the control and evaluation device 100 can be designed to open the second semiconductor switch 30 or to control it into a blocking state in response to a detected faulty operation.

[0030] In order to be able to detect a faulty operation of the switching device 10, a fault detection device, for example a measuring device 50, which is designed to measure a current through the current path 10, can be implemented in the switching device 10, wherein the control and evaluation device 100 is designed to detect a faulty operation in response to the measurement result of the measuring device 50.

[0031] Advantageously, the switching device 10 can have a housing 130, in particular a mounting rail housing, in which, among other things, the current path 110, the control and evaluation device 100 and the detection device 70 can be arranged, wherein the housing 130 and the relay 40 can each be designed for mechanical and electrical coupling to one another.

[0032] In the plugged-in state of the relay 40, a first coil terminal 43 can be electrically connected to the input terminal 20 and a second coil terminal 44 can be electrically connected to the detection device 70.

[0033] Preferably, the switching device 10 can have a timer 105 assigned to the control and evaluation device 100, which is designed to start the expiration of the predetermined time in response to the pulling of the relay 40, wherein the control and evaluation device 100 can be designed to i) detect when the predetermined time has expired, and ii) set the switching device 10 to the first operating state in response to the elapsed predetermined time, wherein in the first operating state the output terminal 21 is electrically connected to the input terminal 20.

Claims

1. Manually resettable switching device (10) which can be controlled into a first or a second operating state, compring: a current path (110) with an input terminal (20), to which an input voltage can be applied, and with an output terminal (21), a manually pluggable relay (40) having a coil (42) and a switching element (41) which is switched into the current path (110) when the relay (40) is plugged in, a control and evaluation device (100) which is designed to detect faulty operation of the switching device (10) and, in response thereto, to set the switching device (10) to the second operating state, a detection device (70) which is electrically connected to the control and evaluation device (100) and is designed to signal to the control and evaluation device (100) whether the relay (40) is plugged in or unplugged, wherein the control and evaluation device (100) is further designed i) to recognize whether the relay (40) has been unplugged after a detected faulty operation and plugged in again after a predetermined time has elapsed, and if so, ii) to set the switching device (10) to the first operating state.

2. Switching device according to one of the preceding claims, characterized by a first semiconductor switch (80) which can be actuated by the control and evaluation device (100), wherein the control and evaluation device is designed to de-energize the coil (42) of the relay (40) by means of the semiconductor switch (80) in response to a detected faulty operation.

3. Switching device according to claim 2, characterized in that the first semiconductor switch (80) is connected in parallel with the detection device (70), and in that the first semiconductor switch (80) and the detection device (70) are connected in series with the coil (42) when the relay (40) is plugged in.

4. Switching device according to one of the preceding claims, characterized in that the detection device (70) comprises a voltage divider (71, 72).

5. Switching device according to one of the preceding claims, characterized by a second semiconductor switch (30) which can be actuated by the control and evaluation device (100) and is connected in series with the switching element (41) of the relay (40) in the current path (110), wherein the control and evaluation device (100) is designed to open the second semiconductor switch (30) in response to a detected faulty operation.

6. Switching device according to one of the preceding claims, characterized by a measuring device (50) which is designed to measure a current through the current path (110), wherein the control and evaluation device (100) is designed to detect a faulty operation in response to the measurement result of the measuring device (50).

7. Switching device according to one of the preceding claims, characterized in that the switching device (10) has a housing (130), in particular a mounting rail housing, in which the current path (110), the control and evaluation device (100) and the detection device (70) are arranged, and in that the housing (130) and the relay (40) are each designed for mechanical and electrical coupling to one another.

8. Switching device according to one of the preceding claims, characterized in that, when the relay (40) is plugged in, a first coil terminal (43) is electrically connected to the input terminal (20) and a second coil terminal (44) is electrically connected to the detection device (70).

9. Switching device according to one of the preceding claims, characterized by a timer (105) which is assigned to the control and evaluation device (100) and which is designed to start the expiry of the predetermined time in response to the pulling of the relay (40), wherein the control and evaluation device (100) is designed i) to recognize when the predetermined time has elapsed, and to ii) set the switching device (10) to the first operating state in response to the elapsed predetermined time, wherein in the first operating state the output terminal (21) is electrically connected to the input terminal (20).