An input interface circuit

Abstract

The application provides an input interface circuit, relay contact points pass through an input interface, a conditioning control circuit and a first isolation module in sequence, and are connected to an input end of a controller; and then an input signal of the relay contact points can be collected to the controller. An output end of the controller is connected to a control end of the conditioning control circuit through a second isolation module and outputs a wet current control signal; when the conditioning control circuit transmits a high-level collected signal through the input interface, the input interface can be short-circuited to the ground according to a duty ratio of the wet current control signal; when the duty ratio is greater than a preset value, a corresponding pulse short-circuit current formed by the input interface is used as the wet current to clean the relay contact points. Therefore, the application can realize integrated design of cleaning of the relay contact points and signal collection of the input interface, and the problems of low equipment working reliability and high cost in the prior art are avoided.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to an input interface circuit. Background Technology

[0002] In the rail transit sector, a large number of signal relays are used in train-mounted signaling equipment and signal machinery rooms, primarily for signal transmission and status detection, playing a crucial role in the safe operation of trains. In practical applications, reliable contact of the relay contacts is a key indicator of relay performance. However, due to environmental factors, including but not limited to air humidity, temperature, and floating solid contaminants, relay contacts may corrode or become contaminated, preventing reliable contact and affecting signal transmission and detection. Therefore, cleaning of the relay contacts is necessary.

[0003] The common method is to apply a pulsed current signal, i.e., a wetting current, to the relay signal path, causing arcing at the relay contacts and thus cleaning them. The system typically uses an input interface circuit to acquire the relay's node signal status. Since the wetting current is a pulsed current signal with a relatively large current value, it may damage the input interface circuit. Therefore, cleaning the relay contacts may conflict with the cleaning process of the input interface circuit.

[0004] In existing technologies, manual cleaning of relay contacts involves first disconnecting the input interface circuit from the relay, then connecting the wetting current cleaning device to the relay to clean the contacts. This method is cumbersome, requires periodic manual intervention, and cannot achieve automated control. An automated solution also exists in the existing technology, which involves designing a wetting current control circuit alongside the input interface circuit, such as... Figure 1 As shown, the software periodically controls the switching action, connecting the wetting current control circuit to the relay while disconnecting it from the input interface circuit; after cleaning is complete, the relay is reconnected to the input interface circuit; however, this solution requires the design of two circuit modules, and the switching of the circuits leads to low equipment reliability and high cost. Summary of the Invention

[0005] In view of this, this application provides an input interface circuit to achieve an integrated design for cleaning relay contact points and acquiring input interface signals.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] This application provides an input interface circuit, including: an input interface, a controller, a conditioning control circuit, a first isolation module, and a second isolation module; wherein,

[0008] The outer side of the input interface is used to connect relay contacts;

[0009] The input interface is connected to the input terminal of the controller via the conditioning control circuit and the first isolation module in sequence.

[0010] The output terminal of the controller is connected to the control terminal of the conditioning control circuit through the second isolation module, and outputs a wetting current control signal.

[0011] The conditioning control circuit is used to control the input interface to be shorted to ground according to the duty cycle of the wetting current control signal when the input interface transmits a high-level acquisition signal; and when the duty cycle is greater than a preset value, to use the corresponding pulse short-circuit current formed on the input interface as the wetting current to clean the relay contact points.

[0012] Optionally, the conditioning control circuit includes: a data acquisition circuit, a switching transistor, and a control circuit; wherein,

[0013] The input terminal of the acquisition circuit is connected to the inside of the input interface;

[0014] The output terminal of the acquisition circuit is connected to the input terminal of the controller through the first isolation module;

[0015] The switching transistor and the current-limiting resistor are connected in series between the inside of the input interface and ground;

[0016] The control terminal of the switching transistor is connected to the output terminal of the controller in sequence through the control circuit and the second isolation module.

[0017] Optionally, the acquisition circuit includes: a first resistor, a second resistor, a third resistor, and a first comparator; wherein,

[0018] The inner side of the input interface is grounded through the first resistor, the second resistor, and the third resistor in sequence;

[0019] The connection point between the second resistor and the third resistor is connected to the non-inverting input of the first comparator;

[0020] The inverting input of the first comparator receives the first reference voltage;

[0021] The output terminal of the first comparator serves as the output terminal of the acquisition circuit.

[0022] Optionally, the control circuit includes: a conditioning module, a second comparator, a first diode, and a second diode; wherein,

[0023] The conditioning module is used to receive the wetting current control signal through the first isolation module and generate an excitation control signal accordingly.

[0024] The non-inverting input of the second comparator receives the excitation control signal;

[0025] The inverting input of the second comparator receives the second reference voltage;

[0026] The output terminal of the second comparator is connected to the cathode of the first diode and the control terminal of the switching transistor, respectively.

[0027] The positive terminals of the first diode and the second diode are both connected to the connection point of the first resistor and the second resistor;

[0028] The negative terminal of the second diode is connected to the power supply.

[0029] Optionally, the switching transistor is a field-effect transistor.

[0030] Optionally, the input terminal of the switching transistor is connected to the inside of the input interface;

[0031] The output terminal of the switching transistor is connected to one end of the current-limiting resistor;

[0032] The other end of the current-limiting resistor is grounded.

[0033] Optionally, the first isolation module is an opto-isolation module.

[0034] Optionally, the second isolation module is an opto-isolation module.

[0035] Optionally, the controller is a microcontroller unit (MCU).

[0036] The input interface circuit provided in this application has an outer side for connecting relay contacts, and an inner side connected to the controller's input terminal via a conditioning control circuit and a first isolation module. This allows the input signal from the relay contacts to be acquired by the controller. Furthermore, the controller's output terminal is connected to the control terminal of the conditioning control circuit via a second isolation module, outputting a wetting current control signal. When the input interface transmits a high-level acquisition signal, the conditioning control circuit controls the input interface to be short-circuited to ground according to the duty cycle of the wetting current control signal. Moreover, when the duty cycle is greater than a preset value, the corresponding pulse short-circuit current generated by the input interface can be used as the wetting current to clean the relay contacts. Therefore, this application achieves an integrated design for cleaning relay contacts and acquiring input interface signals, eliminating the need for switching back and forth and designing additional circuits for wetting current testing, thus avoiding the problems of low equipment reliability and high cost in existing automated solutions. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0038] Figure 1 A schematic diagram of the structure of an automated solution for cleaning relay contact points provided by existing technology;

[0039] Figure 2 This is a schematic diagram of the input interface circuit provided in an embodiment of this application;

[0040] Figure 3 A schematic diagram of a specific structure of the input interface circuit provided in an embodiment of this application;

[0041] Figure 4 A circuit diagram of the conditioning control circuit in the input interface circuit provided in the embodiments of this application;

[0042] Figure 5 This is a schematic diagram of an optional waveform of the wetting current control signal provided in an embodiment of this application. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0045] This application provides an input interface circuit to achieve an integrated design for cleaning relay contact points and acquiring input interface signals.

[0046] See Figure 2The input interface circuit includes: an input interface 10, a controller 40, a conditioning control circuit 20, a first isolation module 30, and a second isolation module 50; wherein:

[0047] The outer side of the input interface 10 is used to connect relay contacts. The inner side of the input interface 10 is connected to the input terminal of the controller 40 through the conditioning control circuit 20 and the first isolation module 30 in sequence.

[0048] The output of the controller 40 is connected to the control terminal of the conditioning control circuit 20 through the second isolation module 50.

[0049] Since the input signals of the relay contacts connected to input interface 10 are mostly high-voltage signals, reaching over 100 volts in practical applications, isolation design is adopted for the control and acquisition signals in the system. In practical applications, the first isolation module 30 can be an opto-isolation module, such as an optocoupler isolator, but is not limited to this; the second isolation module 50 can also be an opto-isolation module, such as an optocoupler isolator, but is not limited to this; both can be determined according to their specific application environment, as long as they can achieve isolated output and acquisition of signals, other implementation forms in the prior art are also within the protection scope of this application.

[0050] In addition, the controller 40 can be implemented using an MCU (Microcontroller Unit), but it is not limited to this.

[0051] The specific working principle is as follows:

[0052] The input interface 10 transmits the input signal from the relay contact point to the controller 40 after passing through the conditioning control circuit 20 and then the isolation of the first isolation module 30, thus completing the acquisition of the input signal from the relay contact point.

[0053] When cleaning of the relay contacts is required, the software in the controller 40 can control the generation of a wetting current control signal, which is then sent to the conditioning control circuit 20 via the second isolation module 50. The second isolation module 50 is used to isolate the digital signal circuit in the controller 40 from the conditioning control circuit 20, preventing the influence and interference of external circuits.

[0054] The conditioning control circuit 20 is used to control the input interface 10 to be shorted to ground according to the duty cycle of the wetting current control signal when the input interface 10 transmits a high-level acquisition signal; and when the duty cycle is greater than a preset value, the corresponding pulse short-circuit current generated on the input interface 10 is used as the wetting current to clean the relay contact points.

[0055] Specifically, a switch capable of short-circuiting the control input interface 10 can be installed inside the conditioning control circuit 20. The opening and closing of the switch is controlled by the wetting current control signal, thereby generating a wetting current in the path between the input interface 10 and the relay contact point.

[0056] The wetting current control signal is specifically a pulse signal. The duty cycle of the level controlling the switch closure is adjustable to regulate the duration during which the input interface 10 is shorted to ground within the pulse period, thereby changing the equivalent current magnitude of the pulse short-circuit current formed on the input interface 10. When the duty cycle is greater than the preset value, the pulse short-circuit current reaches the minimum current sufficient to maintain a small arc at the relay contact points. This current can then act as a wetting current, removing dirt and corrosion from the surface of the relay contact points to maintain them in optimal working condition. The preset value is not limited; it only needs to ensure the relay contact points are clean.

[0057] The input interface circuit provided in this embodiment enables the relay contact points to sequentially connect to the input terminal of the controller 40 via the input interface 10, the conditioning control circuit 20, and the first isolation module 30, thereby acquiring the input signal from the relay contact points to the controller 40. Furthermore, the output terminal of the controller 40 outputs a wetting current control signal to the conditioning control circuit 20 through the second isolation module 50. This allows the conditioning control circuit 20 to control the input interface 10 to be short-circuited to ground according to the duty cycle of the wetting current control signal when the input interface 10 transmits a high-level acquisition signal. Moreover, when the duty cycle is greater than a preset value, the corresponding pulse short-circuit current generated by the input interface 10 can be used as the wetting current to clean the relay contact points. Therefore, this embodiment not only achieves automated control of the wetting current but also integrates relay contact cleaning and input interface 10 signal acquisition, eliminating the need for switching back and forth and designing additional circuits for wetting current testing. This avoids the problems of low equipment reliability and high cost in existing automated solutions.

[0058] Based on the previous embodiment, this embodiment provides some specific examples of the implementation structure of the conditioning control circuit 20 in the input interface circuit. For example, see [link to relevant documentation]. Figure 3 The conditioning control circuit 20 includes: a data acquisition circuit 201, a switching transistor Q0, and a control circuit 202; wherein:

[0059] The input terminal of the acquisition circuit 201 is connected to the inside of the input interface 10.

[0060] The output of the acquisition circuit 201 is connected to the input of the controller 40 through the first isolation module 30.

[0061] The switching transistor Q0, acting as an internal switch within the conditioning control circuit 20 described in the above embodiment, is connected in series with the current-limiting resistor R0 between the inner side of the input interface 10 and ground. The function of the current-limiting resistor R0 is to limit the short-circuit current when the switching transistor Q0 is turned on. Specifically, it can be as follows... Figure 3 As shown, the input terminal of the switch Q0 is connected to the inside of the input interface 10, and the output terminal of the switch Q0 is connected to one end of the current limiting resistor R0, while the other end of the current limiting resistor R0 is grounded. In practical applications, the series connection order between the switch Q0 and the current limiting resistor R0 can also be interchanged. This will not be elaborated or shown here, but can be determined according to the specific application environment, and all of them are within the protection scope of this application.

[0062] The control terminal of the switching transistor Q0 is connected to the output terminal of the controller 40 via the control circuit 202 and the second isolation module 50. That is, the wetting current control signal output by the controller 40 is transmitted through the isolation of the second isolation module 50 and then through the control circuit 202 to the control terminal of the switching transistor Q0.

[0063] In one example, the switch Q0 can be a MOSFET (Metal-Oxide Semiconductor Field Effect Transistor), but it is not limited to this and can be chosen depending on the specific application environment.

[0064] In practical applications, such as Figure 4 As shown, the acquisition circuit 201 may specifically include: a first resistor R1, a second resistor R2, a third resistor R3, and a first comparator U1; wherein: the inner side of the input interface 10 is grounded through the first resistor R1, the second resistor R2, and the third resistor R3 in sequence; the connection point of the second resistor R2 and the third resistor R3 is connected to the non-inverting input terminal of the first comparator U1 (e.g., ...). Figure 4 The Y pin within U1 shown in the diagram); the inverting input of the first comparator U1 (as shown in the diagram). Figure 4 The X pin within U1 (shown in the diagram) receives the first reference voltage V1; the output of the first comparator U1 serves as the output of the acquisition circuit 201, through... Figure 2 The first isolation module 30 shown is connected to the input terminal of the controller 40.

[0065] Since the input signal level of the relay contact points connected to input interface 10 is generally high, reaching hundreds of volts, it is usually not used directly and requires voltage division. Therefore, through the first resistor R1, the second resistor R2, and the third resistor R3, a resistor voltage divider and current limiter are performed, which serves as the non-inverting input terminal of the first comparator U1 (e.g., ...). Figure 4The Y pin within U1 shown in the diagram provides the input. The values ​​of the first resistor R1, the second resistor R2, and the third resistor R3 can be set according to the specific level of the input signal received by the input interface 10, and are not limited here.

[0066] In addition, such as Figure 4 As shown, the control circuit 202 may specifically include: a conditioning module, a second comparator U2, a first diode D1, and a second diode D2; wherein: the conditioning module is used to receive the wetting current control signal through the first isolation module 30, and generate an excitation control signal according to the wetting current control signal; the non-inverting input terminal of the second comparator U2 (e.g., Figure 4 The Y pin within U2 shown in the diagram receives the excitation control signal; the inverting input of the second comparator U2 (as shown in the diagram) receives the excitation control signal. Figure 4 The X pin in U2 (shown in the diagram) receives the second reference voltage V2; the output of the second comparator U2 is connected to the negative terminal of the first diode D1 and the control terminal of the switching transistor Q0, respectively; the positive terminals of the first diode D1 and the second diode D2 are both connected to the junction of the first resistor R1 and the second resistor R2; the negative terminal of the second diode D2 is connected to the power supply VCCD.

[0067] In this control circuit 202, the unidirectional conduction characteristics of the first diode D1 and the second diode D2 are utilized to clamp the potential at the connection point of the first resistor R1 and the second resistor R2. Ignoring the diode forward voltage, the voltage at this connection point switches between the voltage of the power supply VCCD and 0 voltage, ensuring that the non-inverting input of the first comparator U1 (e.g., ...) is... Figure 4 The voltage received by the Y pin in U1 shown in the diagram is switched between two fixed values.

[0068] The first reference voltage V1 and the second reference voltage V2 mentioned above are generally implemented by resistor voltage division. Their specific values ​​can be determined according to actual needs, and are not limited here.

[0069] Combination Figure 4 The working principle of the conditioning control circuit 20 is as follows:

[0070] The conditioning module generates an excitation control signal based on the wetting current control signal. Then, the excitation control signal is compared with the first reference voltage V1 by the second comparator U2 to generate a level control signal, thereby controlling the switching transistor Q0 to turn on or off.

[0071] When the switch Q0 is turned on, a short circuit occurs between the input interface 10 and ground, generating a large short-circuit current signal in the path containing the input interface 10. When the switch Q0 is turned off, this short-circuit current signal is not generated. The wetting current control signal is a pulse signal that can periodically control the on and off states of the switch Q0. Therefore, adjusting the duty cycle, or pulse width, of the wetting current control signal controls the on-time of the switch Q0 and also adjusts the equivalent current of the path. Since the wetting current is the minimum current required to maintain a small arc at the device's contact points, the duty cycle can be controlled to be greater than a preset value, increasing the on-time of the switch Q0 and thus generating the wetting current.

[0072] like Figure 5 As shown, when a wetting current is needed to clean the aforementioned path, the wetting current control signal is set to wetting current pulse T2, corresponding to a large duty cycle; while when the input signal of input interface 10 needs to be acquired, the wetting current control signal can be set to acquisition pulse T1, corresponding to a small duty cycle. For example, when the duty cycle is less than a small threshold and the equivalent current of the aforementioned path can be ignored, the input signal can be acquired.

[0073] The first comparator U1 is used to acquire the input signal received by the input interface 10. When the input signal is a low-level signal, the output of the first comparator U1 is also low-level.

[0074] When the input signal is high, the outputs of the first comparator U1 and the second comparator U2 are made the same under the action of the first diode D1 and the second diode D2. The output of the second comparator U2 is controlled by the wetting current control signal. Therefore, when the input signal is high, the output of the first comparator U1 is controlled by the wetting current control signal.

[0075] To achieve integrated design of wetting current control and input signal acquisition, the wetting current control signal is designed as a high-frequency continuous pulse signal when acquiring the input signal. When the input signal is low, the output of the first comparator U1 is low, and the controller 40 can determine that the input signal is low; when the input signal is high, the output of the first comparator U1 is a continuous pulse signal, and the controller 40 can determine that the input signal is high.

[0076] In this embodiment, the controller 40 generates a wetting current control signal, which is ultimately reflected in the input interface circuit to generate a series of pulse current signals. This forms a wetting current that cleans the relay contacts, improving the reliability of the relay device. Furthermore, the integration of wetting current control and input signal acquisition is ingenious, eliminating the need for switching back and forth or designing additional circuits for wetting current testing; the function can be achieved solely through software control. Additionally, the circuit is simple, control is convenient and easy, highly reliable, and low-cost.

[0077] Similar or identical parts between the various embodiments in this specification can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0078] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0079] The features described above regarding the disclosed embodiments can be substituted for or combined with each other to enable those skilled in the art to implement or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An input interface circuit, characterized by The utility model relates to a relay contact cleaning device, including: input interface, controller, conditioning control circuit, first isolation module and second isolation module, wherein, the outside of input interface is used for connecting relay contact contact point; the inside of input interface connects the input end of controller through conditioning control circuit and first isolation module; the output end of controller connects the control end of conditioning control circuit through second isolation module and outputs wetting current control signal; conditioning control circuit is used for when the input interface transmits the collection signal of high level, controlling input interface is shorted to ground according to the duty cycle of wetting current control signal, and when the duty cycle is greater than preset value, the corresponding pulse short circuit current formed to input interface is used as wetting current to clean relay contact contact point.

2. The input interface circuit of claim 1, wherein, The conditioning control circuit comprises a collection circuit, a switch tube, and a control circuit. The input end of the collection circuit is connected to the inside of the input interface. The output end of the collection circuit is connected to the input end of the controller through the first isolation module. The switch tube and the current-limiting resistor are connected in series between the inside of the input interface and the ground. The control end of the switch tube is connected to the output end of the controller through the control circuit and the second isolation module.

3. The input interface circuit of claim 2, wherein, The collection circuit comprises a first resistor, a second resistor, a third resistor, and a first comparator. The inside of the input interface is grounded through the first resistor, the second resistor, and the third resistor in sequence. The connection point of the second resistor and the third resistor is connected to the non-inverting input end of the first comparator. The inverting input end of the first comparator receives a first reference voltage. The output end of the first comparator is the output end of the collection circuit.

4. The input interface circuit of claim 3, wherein, The control circuit comprises a conditioning module, a second comparator, a first diode, and a second diode. The conditioning module receives the wetting current control signal through the first isolation module and generates an excitation control signal based on it. The non-inverting input end of the second comparator receives the excitation control signal. The inverting input end of the second comparator receives a second reference voltage. The output end of the second comparator is connected to the negative electrode of the first diode and the control end of the switch tube, respectively. The positive electrode of the first diode and the positive electrode of the second diode are both connected to the connection point of the first resistor and the second resistor. The negative electrode of the second diode is connected to a power supply.

5. The input interface circuit of claim 2, wherein, The switch tube is a field effect transistor.

6. The input interface circuit of claim 2, wherein, The input end of the switch tube is connected to the inside of the input interface. The output end of the switch tube is connected to one end of the current-limiting resistor. The other end of the current-limiting resistor is grounded.

7. The input interface circuit according to any one of claims 1 to 6, characterized in that, The first isolation module is an optoelectronic isolation module.

8. The input interface circuit according to any one of claims 1 to 6, characterized in that, The second isolation module is an optoelectronic isolation module.

9. The input interface circuit according to any one of claims 1 to 6, characterized in that, The controller is a micro control unit (MCU).

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