A dry contact collection module and channel self-checking system

Abstract

The application discloses a dry contact collection module and a channel self-checking system, relates to the technical field of industrial control, and can make the module internal light MOS relay and triode switch protection circuit work through the GPIO pin of a micro control unit in the case of external control power input failure, and then output the control power for collecting channels. In addition to being capable of collecting external dry contact input signals, the module has reverse protection and short circuit protection functions, and can not damage the devices on the collection path in the case that the external input is an active contact. The module can detect whether the working state of the channel is normal before the external dry contact signal enters, make a preliminary judgment and analysis, and timely adjust according to the abnormal state to ensure the correctness of the external signal collection.

Description

Technical Field

[0001] This invention relates to the field of industrial control technology, and in particular to a dry contact acquisition module and channel self-testing system that can achieve redundant power supply. Background Technology

[0002] In the field of industrial control, besides analog signal acquisition technology, passive switch signal acquisition technology is also a key component of industrial automation control systems. Various PLCs and DCS products contain separate dry contact acquisition modules. Depending on their size, dry contact acquisition modules can contain varying numbers of dry contact acquisition channels. These channels can be designed with path isolation, group isolation, or no isolation. The acquired dry contact information is processed by the module's microcontroller unit or FPGA and then communicates with the main control module of the entire system via buses such as RS485 and RS422 to upload data. The main control module detects the received data and provides timely feedback, thereby issuing early warnings for abnormal operating conditions in the control field.

[0003] Existing Solution 1 uses a master-slave optocoupler design to acquire switch signals, and its principle block diagram is as follows: Figure 6 As shown. The control signal output by the microcontroller unit is used to turn the secondary acquisition optocoupler U2 on and off after passing through the base current limiting resistor R5. The high and low levels of this control signal are affected by the external control power supply voltage.

[0004] 1. When the external control power supply voltage is low, the microcontroller acquires a low-level signal through the power detection circuit, and then controls the signal output to be high, which turns on NPN transistor Q2 and PNP transistor Q1, causing the acquisition circuit gain to increase. The switch status output signal is determined by the parallel output of the main and auxiliary optocouplers U1 and U2.

[0005] 2. When the external control power supply voltage is high, the microcontroller acquires a high-level signal through the power detection circuit, and then controls the signal output to be low, so that NPN transistor Q2 is turned off and PNP transistor Q1 is turned off. The switch status output signal is determined by the output of the main optocoupler U1.

[0006] The acquisition path of Scheme 1 is equipped with a rectifier diode D1, a reverse protection diode D3, a Zener diode D2, and a detection circuit with an external input control power supply. However, it lacks a handling method when there is no external control power input. For the existing Scheme 1, if there is no external control power input or the external control power input is too low to turn on the optocoupler, but a switching input signal is present, the problem is that the microcontroller will still receive a low-level signal through the power detection circuit, and then the control signal output will be high, turning on the NPN transistor Q2 and the PNP transistor Q1. However, since the output terminals of the main and auxiliary optocouplers U1 and U2 are not turned on, the switching status output detection pin of the microcontroller will still detect a low level, resulting in a false judgment that there is no switching input, which poses a certain safety hazard.

[0007] Furthermore, although the acquisition path is equipped with a main and secondary optocoupler configuration, the design of the series input terminal also has certain hidden dangers. If R3 is short-circuited, the main optocoupler will lose its function. If the external control power input is high enough to turn on the secondary optocoupler and there is a switch input signal, the problem is that the microcontroller will still receive a high-level signal through the power detection circuit, and then the control signal output will be low, causing the NPN transistor Q2 and the PNP transistor Q1 to turn off. In this case, both the main and secondary optocouplers U1 and U2 will lose their function, and the switch status output detection pin of the microcontroller will still detect a low level, thus generating a false judgment that there is no switch input. Without self-test, it is impossible to locate the approximate location of the fault and make timely corrections.

[0008] The existing scheme 2's switch signal acquisition circuit uses a single optocoupler and a Schmitt inverter as the main acquisition channel devices. For the detailed acquisition circuit of dry contact signals, see below. Figure 7 As shown.

[0009] Figure 7 In the diagram, An and Bn are dry contact input terminals. The 24V auxiliary power supply is connected in series with diode D4 and then connected to one end of the switch S1 to be acquired (assuming a 10K resistor is connected in parallel at S1). The other end is connected to Bn and enters the switch signal acquisition channel. Inside the acquisition channel, series resistors R7 and R8, optocoupler U3, and diodes D5 and D6 are connected to the reference ground of the auxiliary power supply. The output terminal R9 of the optocoupler is used to convert the collector current of the secondary transistor of the optocoupler into voltage, which, together with the second Schmitt inverter U4, completes the reliable transmission of the channel signal. Finally, the acquired switch signal is sent to the processor for processing.

[0010] When the external switch signal S1 is disconnected, the optocoupler U3 on the acquisition path is not working, the input of the Schmitt inverter U4 is at a high level of 3.3V, and the main processor detects a low level at the output. When the external switch signal S1 is closed, the optocoupler U3 on the acquisition path is working, the input of the Schmitt inverter U4 changes from a high level of 3.3V to a low level, and the main processor detects the change from low to high level at the output. The processor maps the change of the external switch signal through internal logic operations.

[0011] Scheme 2 lacks a detection circuit for external input control power, making it unable to handle external input power failures. Furthermore, it lacks a self-test for the acquisition channel. For Scheme 2, if an external switch is closed and a switching signal is input, but the resistor R8 in parallel with optocoupler U3 is short-circuited, the problem is that optocoupler U3 is not working. The collector of optocoupler U3's output remains high, and after passing through Schmitt inverter U4, the microcontroller detects a low level, mistakenly interpreting no external switching signal input, thus failing to detect changes in the external system environment in a timely manner. Summary of the Invention

[0012] In view of the above problems, this invention provides a dry contact acquisition module and channel self-testing system to overcome or at least partially solve the above problems. It solves the problem that current dry contact acquisition circuits lack a timed self-test function, relying on manual troubleshooting for fault detection, resulting in low maintenance efficiency and long module downtime. Simultaneously, it addresses the issue that most current systems use an external control power supply to power the acquisition channel separately, causing the acquisition path to malfunction and fail to operate normally when the external input power supply fails. Furthermore, it addresses the lack of reverse protection in the dry contact acquisition path, which insufficiently considers abnormal situations caused by components such as resistor short circuits.

[0013] This invention provides the following solution:

[0014] A dry contact acquisition module and channel self-testing system, comprising:

[0015] External control power supply detection circuit, dry contact acquisition channel circuit, acquisition channel self-test circuit, redundant power supply circuit and microcontroller unit;

[0016] The microcontroller unit is used to perform the following operations:

[0017] After confirming that the module to which the dry contact acquisition channel circuit belongs has started normally after power-on, the redundant power supply circuit is controlled to form a 24VIN_F power supply for the dry contact acquisition channel circuit by outputting a high level through the PWR_CTR pin.

[0018] The self-test circuit of the acquisition channel is enabled by outputting a high level through the CHK1 pin.

[0019] Determine if a high level is detected on pin CH1;

[0020] If no high level is detected, the dry contact acquisition channel circuit is deemed to be malfunctioning, and a prompt message is generated.

[0021] If a high level is detected, it is confirmed that the dry contact acquisition channel circuit has completed the channel self-test normally.

[0022] After confirming the completion of the channel self-test, the redundant power supply circuit is turned off by outputting a low level through the PWR_CTR pin, and the acquisition channel self-test circuit is turned off by outputting a low level through the CHK1 pin.

[0023] After confirming the external control power input, control the dry contact acquisition channel circuit to operate;

[0024] Determine whether both pins CHF_24V and CH1 are detected to be at a high level;

[0025] If no high level is detected, it is determined that the external control power supply input is abnormal. It is then determined whether the external control power supply has been replaced. If the external control power supply has been replaced, the replaced external control power supply is used as the input to provide 24VIN_F power to the dry contact acquisition channel circuit. If the external control power supply has not been replaced, the abnormal external control power supply is disconnected, and the PWR_CTR pin is controlled to output a high level, enabling the redundant power supply circuit to provide 24VIN_F power to the dry contact acquisition channel circuit.

[0026] After confirming that a high level is detected in all cases, it is determined that the external control power supply is normal, and the external control power supply detection is completed.

[0027] The system receives externally input dry contact detection signals and controls the dry contact acquisition channel circuit to complete dry contact signal acquisition after detecting a high level through the CH1 pin.

[0028] Preferably, the external control power supply detection circuit is used to turn on the input terminal of the photoelectric MOS relay after passing through the current limiting resistor when the external control power supply DC24V is input normally, and to turn on the output terminal of the photoelectric MOS relay by lighting the internal light-emitting diode. This allows the microcontroller unit to detect the change in the CHF_24V signal level from the initial low level to the high level, and then perform logical operations in the software to realize the external control power supply detection function.

[0029] Preferably, the external control power supply detection circuit includes rectifier diode D7, rectifier diode D8, reverse protection diode D9, transient voltage suppression diode TVS1, 3.3KΩ resistor R10, 2.2KΩ resistor R11, 10KΩ resistor R12, 0.1uF / 50V filter capacitor C1, 15pF / 100V capacitor C2, and optical MOS relay U5;

[0030] The rectifier diodes D7 and D8 are respectively connected to the two external control power supplies in a one-to-one correspondence.

[0031] Preferably, the redundant power supply circuit includes a bus diode, an overvoltage, undervoltage, and surge protection circuit, an isolated DC-DC converter, and an optical MOS relay and transistor switch protection circuit.

[0032] Preferably, the optical MOS relay and transistor switch protection circuit includes a 4.7KΩ resistor R13, a 1KΩ resistor R14, a 10KΩ resistor R15, an NPN transistor Q3, protection diodes D10 and D11, and an optical MOS relay U6.

[0033] Preferably, the dry contact acquisition channel circuit realizes the acquisition function through a loop composed of optical MOS relay U7 and IN1 / IN2; IN1 and IN2 are the two ends of the dry contact input, respectively.

[0034] Preferably, the dry contact acquisition channel circuit and the channel self-test circuit include a 3.3KΩ resistor R16, a 2.2KΩ resistor R17, a 10KΩ resistor R18, a 0Ω resistor R19, a 330Ω resistor R20, a 1KΩ resistor R21, a 10KΩ resistor R22, a 0.1uF / 50V filter capacitor C3, a 0.1uF / 50V filter capacitor C5, a 15pF / 100V capacitor C4, an NPN transistor Q4, an opto-MOS relay U7, an opto-MOS relay U8, a reverse protection diode D11, and a transient voltage suppression diode TVS2.

[0035] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0036] This application provides a dry contact acquisition module and channel self-testing system. In the event of an external control power input failure, the module internally controls the optical MOS relay and transistor switch protection circuit via the GPIO pin of the microcontroller unit, thereby outputting control power for the acquisition channel. Besides acquiring external dry contact input signals, it also features reverse protection and short-circuit protection, preventing damage to devices in the acquisition path even when the external input is an active contact. It can detect the channel's operating status before the external dry contact signal enters, making a preliminary judgment and analysis, and adjusting promptly based on abnormal conditions to ensure the accuracy of external signal acquisition.

[0037] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0039] Figure 1 This is a flowchart of the acquisition process of a dry contact acquisition module and a channel self-testing system provided in an embodiment of the present invention;

[0040] Figure 2 This is a circuit diagram of the external control power supply detection function provided in an embodiment of the present invention;

[0041] Figure 3 This is a flowchart of the power supply process for generating channel redundancy control within the dry contact acquisition module provided in this embodiment of the invention.

[0042] Figure 4 This is a detailed circuit diagram of the internal power supply switching of the module provided in the embodiment of the present invention;

[0043] Figure 5 This is a detailed circuit diagram of the dry contact acquisition channel with self-test provided in an embodiment of the present invention;

[0044] Figure 6 This is a detailed circuit diagram of the existing solution's switch quantity acquisition channel;

[0045] Figure 7 This is the detailed circuit diagram of the existing scheme 2 switch quantity acquisition channel. Detailed Implementation

[0046] 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 a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0047] See Figure 1 This invention provides a dry contact acquisition module and a channel self-testing system, as shown in the embodiments of the present invention. Figure 1 As shown, the system may include:

[0048] External control power supply detection circuit, dry contact acquisition channel circuit, acquisition channel self-test circuit, redundant power supply circuit and microcontroller unit;

[0049] The microcontroller unit is used to perform the following operations:

[0050] After confirming that the module to which the dry contact acquisition channel circuit belongs has started normally after power-on, the redundant power supply circuit is controlled to form a 24VIN_F power supply for the dry contact acquisition channel circuit by outputting a high level through the PWR_CTR pin.

[0051] The self-test circuit of the acquisition channel is enabled by outputting a high level through the CHK1 pin.

[0052] Determine if a high level is detected on pin CH1;

[0053] If no high level is detected, the dry contact acquisition channel circuit is deemed to be malfunctioning, and a prompt message is generated.

[0054] If a high level is detected, it is confirmed that the dry contact acquisition channel circuit has completed the channel self-test normally.

[0055] After confirming the completion of the channel self-test, the redundant power supply circuit is turned off by outputting a low level through the PWR_CTR pin, and the acquisition channel self-test circuit is turned off by outputting a low level through the CHK1 pin.

[0056] After confirming the external control power input, control the dry contact acquisition channel circuit to operate;

[0057] Determine whether both pins CHF_24V and CH1 are detected to be at a high level;

[0058] If no high level is detected, it is determined that the external control power supply input is abnormal. It is then determined whether the external control power supply has been replaced. If the external control power supply has been replaced, the replaced external control power supply is used as the input to provide 24VIN_F power to the dry contact acquisition channel circuit. If the external control power supply has not been replaced, the abnormal external control power supply is disconnected, and the PWR_CTR pin is controlled to output a high level, enabling the redundant power supply circuit to provide 24VIN_F power to the dry contact acquisition channel circuit.

[0059] After confirming that a high level is detected in all cases, it is determined that the external control power supply is normal, and the external control power supply detection is completed.

[0060] The system receives externally input dry contact detection signals and controls the dry contact acquisition channel circuit to complete dry contact signal acquisition after detecting a high level through the CH1 pin.

[0061] In a specific implementation, the embodiment of this application can provide the external control power supply detection function circuit so that, under normal input of external control power supply DC24V, after passing through the current limiting resistor, the input terminal of the opto-MOS relay is turned on, and the internal light-emitting diode is lit, so that the output terminal of the opto-MOS relay is turned on, so that after the microcontroller detects the change of the CHF_24V signal level from the initial low level to the high level, the microcontroller performs logical operations in the software to realize the external control power supply detection function.

[0062] The external control power supply detection circuit includes rectifier diode D7, rectifier diode D8, reverse protection diode D9, transient voltage suppression diode TVS1, 3.3KΩ resistor R10, 2.2KΩ resistor R11, 10KΩ resistor R12, 0.1uF / 50V filter capacitor C1, 15pF / 100V capacitor C2, and optical MOS relay U5;

[0063] The rectifier diodes D7 and D8 are respectively connected to the two external control power supplies in a one-to-one correspondence.

[0064] The redundant power supply circuit includes a bus diode, an overvoltage, undervoltage, and surge protection circuit, an isolated DC-DC converter, and an optical MOS relay and transistor switch protection circuit.

[0065] The optical MOS relay and transistor switch protection circuit includes a 4.7KΩ resistor R13, a 1KΩ resistor R14, a 10KΩ resistor R15, an NPN transistor Q3, protection diodes D10 and D11, and an optical MOS relay U6.

[0066] The dry contact acquisition channel circuit realizes the acquisition function through the loop composed of optical MOS relay U7 and IN1 / IN2; IN1 and IN2 are the two ends of the dry contact input, respectively.

[0067] The dry contact acquisition channel circuit includes a 3.3KΩ resistor R16, a 2.2KΩ resistor R17, a 10KΩ resistor R18, a 0Ω resistor R19, a 330Ω resistor R20, a 1KΩ resistor R21, a 10KΩ resistor R22, a 0.1uF / 50V filter capacitor C3, a 0.1uF / 50V filter capacitor C5, a 15pF / 100V capacitor C4, an NPN transistor Q4, an opto-MOS relay U7, an opto-MOS relay U8, a reverse protection diode D11, and a transient voltage suppression diode TVS2.

[0068] The dry contact acquisition module and channel self-test system provided in this application introduce a self-test circuit composed of optical MOS relays. The microcontroller controls the acquisition path self-test before connecting to the external dry contact, eliminating acquisition abnormalities caused by its own faults. Secondly, an isolated DC / DC power supply module is used to design a redundant power supply circuit for the acquisition channel, ensuring normal operation of the channel in the event of an external control power supply failure. Finally, reverse protection diodes, TVS diodes, and other protection devices are set on the acquisition path, and a dual current-limiting resistor configuration is used on the path to avoid damage to the downstream optical MOS relay caused by the external control power supply input to the dry contact acquisition channel when a single resistor is short-circuited, which would prevent the dry contact acquisition channel from working properly.

[0069] The dry contact acquisition module and channel self-test system provided in this application effectively solve the problems that the lack of self-test will make it impossible to locate the approximate location of the fault and make timely corrections. When the external control power supply voltage is low or there is no power supply voltage input, the microcontroller unit will receive a low-level signal through the designed external control power supply detection circuit, and then turn on the redundant power supply circuit to output the control power supply voltage, so that the switch quantity acquisition circuit can work normally.

[0070] The dry contact acquisition module and channel self-test system provided in this application effectively solve the problems of misjudging the absence of external switching signal input, which leads to the inability to detect changes in the external system environment in a timely manner. The current-limiting resistor is not connected in parallel with the optocoupler but is connected in series in the circuit. When one of the resistors is short-circuited, it will not affect the normal operation of the entire acquisition path. At the same time, the system changes the connection method of the output terminal of the optical MOS relay. The output current-limiting resistor and the switching status detection signal are connected on both sides of the output terminal of the optical MOS relay, eliminating the Schmitt inverter and thus achieving the same switching acquisition effect.

[0071] The system provided in the embodiments of this application will be described in detail below with reference to specific circuit diagrams.

[0072] The dry contact acquisition module and channel self-test system provided in this application embodiment all follow domestic design principles, and all components are domestically produced. The system mainly includes an external control power supply detection circuit, a dry contact acquisition channel circuit, an acquisition channel self-test circuit, and a redundant power supply circuit. The external control power supply detection function circuit is as follows: Figure 2 As shown.

[0073] The power detection circuit of this invention supports one or two external control power inputs (24VIN_F1 and 24VIN_F2). D7 and D8 are rectifier diodes, D9 is a reverse protection diode, TVS1 is a transient voltage suppressor diode, R10 is a 3.3KΩ resistor, R11 is a 2.2KΩ resistor, R12 is a 10KΩ resistor, C1 is a 0.1uF / 50V filter capacitor, C2 is a 15pF / 100V capacitor, and U5 is an opto-MOS relay. 24VIN_F is the combined DC 24V voltage, and the microcontroller unit_3.3V is the internal DC 3.3V voltage of the module.

[0074] The operation flow of the acquisition channel is summarized as follows: Under normal external control power supply DC24V input, after passing through the current limiting resistor, the input terminal of the opto-MOS relay is turned on, the internal light-emitting diode lights up, and thus the output terminal of the opto-MOS relay is turned on. Since there is already a DC3.3V power supply at the output terminal, the microcontroller detects the change in the CHF_24V signal level from the initial low level to the high level. The microcontroller performs logic operations through software to realize the external control power supply detection function.

[0075] The dry contact acquisition module provided in this application provides a redundant control power supply process for the acquisition channel generated internally, as well as a detailed circuit for power supply switching within the module, as follows: Figure 3 and Figure 4 As shown.

[0076] Figure 3 In the diagram, 24V1 and 24V2 are two redundant external DC power inputs that power the module. After passing through a bus diode, they form the 24V DC power supply within the module. The 24V then passes through an overvoltage, undervoltage, overcurrent, and surge protection circuit formed by a hot-swappable chip to form VCC_24V. VCC_24V then passes through an isolated DC / DC module to form TEST_24V. The activation of the isolated DC / DC module is controlled by the microcontroller unit. When there is no external control power input to the acquisition channel, the GPIO pin PWR_CTR of the microcontroller unit outputs a high level to enable the DC / DC converter, and only then does it output TEST_24V. TEST_24V then... Figure 4 The optical MOS relay and transistor switch protection circuit shown form a 24VIN_F, which is used as the control power supply for the acquisition channel.

[0077] Figure 4In this configuration, the PWR_CTR pin, besides serving as the DC / DC enable control pin, also acts as the enable pin for the NPN transistor Q3. That is, in the absence of an external control power supply, it is used for channel power supply switching control. A high-level output from the microcontroller's GPIO pin controls the 24VIN_F signal internally converted by the module to enable the acquisition channel's control power supply. R13 is a 4.7KΩ resistor, R14 is a 1KΩ resistor, R15 is a 10KΩ resistor, Q3 is an NPN transistor, D10 and D11 are protection diodes, and U6 is an opto-MOS relay.

[0078] The control flow is summarized as follows: The high-level signal of the PWR_CTR pin turns on the NPN transistor Q3 after passing through resistors R14 and R15. The input terminal of the opto-MOS relay has a VCC_24V DC power supply. The VCC_24V passes through the current-limiting resistor R13, the opto-MOS relay U6, and the NPN transistor Q3, and is then connected to the internal power ground. The input terminal of U6 is turned on, and the internal LED lights up, causing its output terminal to be turned on. Finally, the TEST_24V converted by the isolated DC / DC converter passes through the output terminal of the opto-MOS relay to form 24VIN_F, which is used as the control power supply for the acquisition channel.

[0079] Figure 5 The detailed circuit for the dry contact acquisition channel for self-testing is as follows: R16 is a 3.3KΩ resistor, R17 is a 2.2KΩ resistor, R18 is a 10KΩ resistor, R19 is a 0Ω resistor, R20 is a 330Ω resistor, R21 is a 1KΩ resistor, R22 is a 10KΩ resistor, C3 / C5 are 0.1uF / 50V filter capacitors, C4 is a 15pF / 100V capacitor, Q4 is an NPN transistor, U7 / U8 are opto-MOS relays, D11 is a reverse protection diode, and TVS2 is a transient voltage suppression diode.

[0080] The dry contact acquisition function is implemented through a circuit consisting of optical MOS relay U7 and IN1 / IN2. IN1 and IN2 are the two ends of the dry contact input, respectively. When the external dry contact input is normal, that is, IN1 and IN2 are closed, the acquisition channel circuit forms a loop with the control power supply 24VIN_F, R16, U7, R17, D11 and the digital ground of the external control power supply. The input terminal of U7 is turned on, and the internal light-emitting diode lights up, causing its output terminal to be turned on. The CH1 pin of the microcontroller detects the change in level from the initial low level to the high level. Then, the microcontroller can identify the external switch input through software, and thus provide early warning of abnormal operating conditions in the control field.

[0081] The self-test function of the acquisition channel is controlled by pin CHK1 of the microcontroller unit. When pin CHK1 outputs a high level, NPN transistor Q4 conducts. The input terminal of opto-MOS relay U8 receives the microcontroller unit's 3.3V DC power supply. This 3.3V power supply passes through current-limiting resistor R20, opto-MOS relay U8, and NPN transistor Q4, and is then connected to the internal power ground. When the input terminal of U8 conducts, the internal LED lights up, causing its output terminal to conduct. Therefore, the acquisition channel circuit forms a loop consisting of control power supply 24VIN_F, resistors R16, U7, R17, D11, R19, U8, and the digital ground of the external control power supply. When the input terminal of U7 conducts, the internal LED lights up, causing its output terminal to conduct. When pin CH1 of the microcontroller unit detects the change in voltage level from low to high, the channel self-test is complete. The internal software control of the microcontroller unit can implement timed high and low level outputs of CHK1 to achieve the timed channel self-test function.

[0082] Furthermore, if an external IN1 is mistakenly input with a DC24V or DC48V voltage signal, due to the unidirectional conductivity of diode D11 on the acquisition channel, no current loop will be formed, thus protecting the subsequent circuit from damage.

[0083] The system introduction provided in the embodiments of this application Figure 4 The redundant power supply circuit shown can effectively switch between external power supply and internal power supply. When the external control power input fails, it can switch to the internal power supply of the module to ensure that the dry contact signal acquisition channel works normally.

[0084] Meanwhile, the hardware selection follows a fully domestic design, using opto-MOS relays, TVS diodes, and reverse protection diodes as isolation and protection devices in the dry contact signal acquisition path. It also adopts a dual-resistor current limiting method to protect the microcontroller and downstream devices in the event of abnormal external control power input or short circuit of a resistor.

[0085] In addition, a channel self-test circuit is introduced. Under the condition of no external control power input, the processor controls the self-test circuit to work and uses the output of the dry contact signal acquisition circuit as the feedback signal, thereby achieving the purpose of detecting whether the working status of the entire circuit is normal. The timed self-test function can be realized through software settings.

[0086] In summary, the dry contact acquisition module and channel self-test system provided in this application can, in the event of an external control power input failure, control the optical MOS relay and transistor switching protection circuit through the GPIO pin of the microcontroller unit to output control power for the acquisition channel. Besides acquiring external dry contact input signals, it also features reverse protection and short-circuit protection, preventing damage to devices in the acquisition path even when the external input is an active contact. It can detect the channel's operating status before the external dry contact signal enters, make a preliminary judgment and analysis, and adjust accordingly to ensure the accuracy of external signal acquisition.

[0087] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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 limitations, 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 said element.

[0088] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0089] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments 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 descriptions in 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 according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A dry contact acquisition module and channel self-testing system, characterized in that, The system includes an external control power supply detection circuit, a dry contact acquisition channel circuit, an acquisition channel self-test circuit, a redundant power supply circuit, and a microcontroller unit. The external control power supply detection circuit, when the external control power supply (DC24V) is input normally, activates the input terminal of the opto-MOS relay after passing through a current-limiting resistor. This activates the internal LED, causing the output terminal of the opto-MOS relay to conduct. This allows the microcontroller unit to detect the change in the CHF_24V signal level from an initial low level to a high level. The microcontroller unit then performs logical operations via software to implement the external control power supply detection function. The redundant power supply circuit includes a bus diode, overvoltage / undervoltage / overcurrent surge protection circuits, an isolated DC-DC converter, and protection circuits for the opto-MOS relay and transistor switch. The microcontroller unit is used to perform the following operations: After confirming that the module to which the dry contact acquisition channel circuit belongs has started normally after power-on, the redundant power supply circuit is controlled to form a 24VIN_F power supply for the dry contact acquisition channel circuit by outputting a high level through the PWR_CTR pin. The self-test circuit of the acquisition channel is enabled by outputting a high level through the CHK1 pin. Determine if a high level is detected on pin CH1; If no high level is detected, the dry contact acquisition channel circuit is deemed to be malfunctioning, and a prompt message is generated. If a high level is detected, it is confirmed that the dry contact acquisition channel circuit has completed the channel self-test normally. After confirming the completion of the channel self-test, the redundant power supply circuit is turned off by outputting a low level through the PWR_CTR pin, and the acquisition channel self-test circuit is turned off by outputting a low level through the CHK1 pin. After confirming the external control power input, control the dry contact acquisition channel circuit to operate; Determine whether both pins CHF_24V and CH1 are detected to be at a high level; If no high level is detected, it is determined that the external control power supply input is abnormal. It is then determined whether the external control power supply has been replaced. If the external control power supply has been replaced, the replaced external control power supply is used as the input to provide 24VIN_F power to the dry contact acquisition channel circuit. If the external control power supply has not been replaced, the abnormal external control power supply is disconnected, and the PWR_CTR pin is controlled to output a high level, enabling the redundant power supply circuit to provide 24VIN_F power to the dry contact acquisition channel circuit. After confirming that a high level is detected in all cases, it is determined that the external control power supply is normal, and the external control power supply detection is completed. It receives externally input dry contact detection signals, and after detecting a high level through pin CH1, controls the dry contact acquisition channel circuit to complete the dry contact signal acquisition.

2. The dry contact acquisition module and channel self-test system according to claim 1, characterized in that, The external control power supply detection circuit includes rectifier diodes D7 and D8, reverse protection diode D9, transient voltage suppressor diode TVS1, 3.3KΩ resistor R10, 2.2KΩ resistor R11, 10KΩ resistor R12, and 0.1... F / 50V filter capacitor C1, 15pF / 100V capacitor C2, optical MOS relay U5; The rectifier diodes D7 and D8 are respectively connected to the two external control power supplies in a one-to-one correspondence.

3. The dry contact acquisition module and channel self-test system according to claim 1, characterized in that, The optical MOS relay and transistor switch protection circuit includes a 4.7KΩ resistor R13, a 1KΩ resistor R14, a 10KΩ resistor R15, an NPN transistor Q3, protection diodes D10 and D11, and an optical MOS relay U6.

4. The dry contact acquisition module and channel self-test system according to claim 1, characterized in that, The dry contact acquisition channel circuit realizes the acquisition function through the loop composed of optical MOS relay U7 and IN1 / IN2; IN1 and IN2 are the two ends of the dry contact input, respectively.

5. The dry contact acquisition module and channel self-test system according to claim 4, characterized in that, The dry contact acquisition channel circuit and channel self-test circuit include a 3.3KΩ resistor R16, a 2.2KΩ resistor R17, a 10KΩ resistor R18, a 0Ω resistor R19, a 330Ω resistor R20, a 1KΩ resistor R21, a 10KΩ resistor R22, a 0.1uF / 50V filter capacitor C3, a 0.1uF / 50V filter capacitor C5, a 15pF / 100V capacitor C4, an NPN transistor Q4, an opto-MOS relay U7, an opto-MOS relay U8, a reverse protection diode D11, and a transient voltage suppression diode TVS2.

Images