Dry contact acquisition module and channel self-checking system

Abstract

The invention discloses a dry contact acquisition module and a channel self-checking system, relates to the technical field of industrial control, and can control an optical MOS (Metal Oxide Semiconductor) relay and a triode switch protection circuit to work through a GPIO (General Purpose Input / Output) pin of a micro-control unit in the module under the condition of input failure of an external control power supply so as to output a control power supply for an acquisition channel. Besides acquisition of external dry contact input signals, the device also has reverse protection and short-circuit protection functions, and can not damage devices on an acquisition access when external input is an active contact. Whether the working state of the channel is normal or not can be detected before an external dry contact signal enters, preliminary judgment and analysis are made, and timely adjustment is carried out according to the abnormal state so as to ensure the correctness of external signal acquisition.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial control, and in particular to a dry contact acquisition module and a channel self-checking system capable of realizing redundant power supply. Background Art

[0002] In the industrial control field, in addition to analog signal acquisition technology, passive switching signal acquisition technology is also a key component of industrial automation control systems. Various PLC 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, with channels designed with either line-to-line isolation, group isolation, or no isolation. The collected dry contact information is processed by the module's microcontroller unit or FPGA, and then communicates with the system's main control module via buses such as RS485 and RS422. The main control module then detects the received data and provides timely feedback, thereby providing early warnings of abnormal operating conditions at the control site.

[0003] The existing solution 1 uses a master and slave optocoupler design to collect switch signals. The principle block diagram is as follows: Figure 6 The control signal output by the microcontroller is used to turn on and off the auxiliary acquisition optocoupler U2 after passing through the base current limiting resistor R5. The high and low levels of the control signal are affected by the external control power supply voltage.

[0004] 1. When the external control power supply voltage is low, the microcontroller unit collects a low-level signal through the power detection circuit, and then controls the signal output to be high, turning on the NPN transistor Q2 and the PNP transistor Q1, thereby increasing the acquisition loop gain. The switch state output signal is determined by the parallel output of the primary and secondary optocouplers U1 and U2.

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

[0006] The acquisition path of the scheme one is provided with a rectifier diode D1, a reverse protection diode D3, a voltage regulator diode D2, and a detection circuit with an external input control power supply, but lacks a processing method when there is no external control power supply input. For the existing scheme one, if there is no external control power supply input or the external control power supply input is low and not enough to make the optocoupler turn on, but there is a switch input signal, then the problem is: the microcontroller will still receive a low-level signal through the power detection circuit, and then the control signal output is high, so that the NPN transistor Q2 is turned on and the PNP transistor Q1 is turned on, but because the output ends of the main and auxiliary optocouplers U1\U2 are not turned on, the switch state output detection pin of the microcontroller still detects a low level, and then misjudges that there is no switch input, which poses certain safety hazards.

[0007] In addition, although the acquisition path is configured with main and auxiliary optocouplers, the design concept of the series input end also has certain hidden dangers. If R3 is short-circuited, the main optocoupler will lose its function. When the external control power input is high enough to make the auxiliary optocoupler turn on, and there is a switch input signal, the problem is: the microcontroller will still receive a high-level signal through the power detection circuit, and then the control signal output is low, causing the NPN transistor Q2 to turn off and the PNP transistor Q1 to turn off, then the main and auxiliary optocouplers U1\U2 will lose their function, and the switch status output detection pin of the microcontroller will still detect a low level, which will lead to a false judgment that there is no switch input. The lack of self-test will make it impossible to locate the approximate position of the fault and make timely corrections.

[0008] The switch quantity acquisition circuit of the existing solution 2 uses a single optocoupler and a Schmitt inverter as the main acquisition channel devices. The detailed acquisition circuit for dry contact signal acquisition is as follows: Figure 7 shown.

[0009] Figure 7 In the example, An and Bn are dry contact input terminals. A 24V auxiliary power supply, connected in series with diode D4, connects to one end of the switch S1 to be collected (assuming a 10K resistor is connected in parallel to S1) through An. The other end connects to Bn and enters the switch acquisition channel. Resistors R7 and R8, an optocoupler U3, and diodes D5 and D6 are connected in series within the acquisition channel to the auxiliary power supply's reference ground. The optocoupler output terminal R9 converts the collector current of the optocoupler's secondary transistor into a voltage, which, together with the second Schmitt inverter U4, ensures reliable channel signal transmission, ultimately sending the collected switch signal to the processor for processing.

[0010] When the external switch signal S1 is disconnected, the optocoupler U3 on the acquisition path does not work, the input end of the Schmitt inverter U4 is a 3.3V high level, and the main processor at the output end detects a low level; when the external switch signal S1 is closed, the optocoupler U3 on the acquisition path works, the input end of the Schmitt inverter U4 changes from a 3.3V high level to a low level, and the main processor at the output end detects the change from a low level to a high level, and the processor maps the changes in the external switch quantity through internal logical operations.

[0011] This second solution lacks a detection circuit for the external input control power supply, making it incapable of responding to external input power failures. Furthermore, this solution lacks self-testing of the acquisition channels. With the existing second solution, if the external switch is closed (i.e., a digital signal is input), but the resistor R8 connected in parallel to the optocoupler U3 is short-circuited, the problem arises: optocoupler U3 is inoperative, and the collector of its output remains high. After passing through Schmitt inverter U4, the microcontroller detects a low level, misjudging the absence of an external digital signal input and failing to promptly detect changes in the external system environment. Summary of the Invention

[0012] In view of the above-mentioned problems, the present invention provides a dry contact acquisition module and channel self-test system for overcoming or at least partially resolving the above-mentioned problems. This solves the problem that current dry contact acquisition circuits lack a timed self-test function, and fault detection relies on manual troubleshooting, resulting in low maintenance efficiency and long module downtime. It also solves the problem that most current acquisition channels are powered solely by external control power supplies. If the external input power fails and no external control power is input, the acquisition channel becomes paralyzed and cannot operate normally. Furthermore, it solves the problem that the dry contact acquisition channel lacks reverse protection, which insufficiently considers abnormal situations caused by short circuits in certain components, such as resistors.

[0013] The present invention provides the following solutions:

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

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

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

[0017] After determining that the module to which the dry contact acquisition channel circuit belongs is powered on and started normally, the redundant power supply circuit is controlled to form the 24VIN_F power supply of the dry contact acquisition channel circuit through the PWR_CTR pin outputting a high level;

[0018] Outputting a high level via the CHK1 pin enables the self-test circuit of the acquisition channel;

[0019] Determine whether the CH1 pin detects a high level;

[0020] If it is determined that no high level is detected, it is determined that the dry contact acquisition channel circuit is abnormal and a prompt message is generated;

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

[0022] After determining that the channel self-test is completed, the redundant power supply circuit is controlled to be turned off by outputting a low level through the PWR_CTR pin, and the acquisition channel self-test circuit is controlled to be turned off by outputting a low level through the CHK1 pin;

[0023] After confirming the input of external control power supply, controlling the operation of the dry contact acquisition channel circuit;

[0024] Determine whether the CHF_24V pin and the CH1 pin are both detected to be high level;

[0025] If it is determined that a high level is not detected, it is determined that the external control power input is abnormal, and it is determined whether the external control power has been replaced; after determining that the external control power has been replaced, the replaced external control power is used as the input of the external control power to provide 24VIN_F power to the dry contact acquisition channel circuit; after determining that the external control power has not been replaced, the abnormal external control power is disconnected, and the PWR_CTR pin is controlled to output a high level, so that the redundant power supply circuit is enabled to provide 24VIN_F power to the dry contact acquisition channel circuit;

[0026] After confirming that a high level is detected, it is determined that the external control power supply is normal, and the external control power supply test is completed;

[0027] Receive the dry contact detection signal input from the outside, and after detecting a high level through the CH1 pin, control the dry contact acquisition channel circuit to complete the dry contact signal acquisition.

[0028] Preferably: the external control power supply detection function circuit is used to, when the external control power supply DC24V input is normal, after passing through the current limiting resistor, turn on the input end of the photoMOS relay, light up the internal light-emitting diode and turn on the output end of the photoMOS relay, so that after the micro control unit detects the change of the CHF_24V signal level from the initial low level to the high level, the micro control unit performs logical operations through software inside to realize the external control power supply detection function.

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

[0030] The rectifier diode D7 and the rectifier diode D8 are respectively used to be connected to 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, overcurrent and surge protection circuit, an isolated DCDC, and a photo 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 an 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 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 optical MOS relay U7, an optical MOS relay U8, a reverse protection diode D11, and a transient voltage suppressor diode TVS2.

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

[0036] The embodiments of the present application provide a dry contact acquisition module and channel self-test system. In the event of an external control power input failure, the module can control the operation of the optical MOS relay and transistor switch protection circuit through the GPIO pin of the microcontroller unit, thereby outputting the control power for the acquisition channel. In addition to being able to acquire external dry contact input signals, it also has reverse protection and short-circuit protection functions, and can prevent damage to devices in the acquisition path when the external input is an active contact. It can detect whether the channel's operating status is normal before the external dry contact signal enters, make preliminary judgments and analyses, and make timely adjustments based on abnormal conditions to ensure the accuracy of external signal acquisition.

[0037] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0039] Figure 1 This is a collection flow chart of a dry contact collection module and a channel self-test system provided by an embodiment of the present invention;

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

[0041] Figure 3 This is a flow chart of the redundant control power supply for generating channels within the dry contact acquisition module provided by an embodiment of the present invention;

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

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

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

[0045] Figure 7 This is the detailed circuit diagram of the switch quantity acquisition channel of the existing solution two. DETAILED DESCRIPTION

[0046] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0047] See also Figure 1 , a dry contact acquisition module and channel self-test system provided by an embodiment of the present invention, such as Figure 1 As shown, the system may include:

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

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

[0050] After determining that the module to which the dry contact acquisition channel circuit belongs is powered on and started normally, the redundant power supply circuit is controlled to form the 24VIN_F power supply of the dry contact acquisition channel circuit through the PWR_CTR pin outputting a high level;

[0051] Outputting a high level via the CHK1 pin enables the self-test circuit of the acquisition channel;

[0052] Determine whether the CH1 pin detects a high level;

[0053] If it is determined that no high level is detected, it is determined that the dry contact acquisition channel circuit is abnormal and a prompt message is generated;

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

[0055] After determining that the channel self-test is completed, the redundant power supply circuit is controlled to be turned off by outputting a low level through the PWR_CTR pin, and the acquisition channel self-test circuit is controlled to be turned off by outputting a low level through the CHK1 pin;

[0056] After confirming the input of external control power supply, controlling the operation of the dry contact acquisition channel circuit;

[0057] Determine whether the CHF_24V pin and the CH1 pin are both detected to be high level;

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

[0059] After confirming that a high level is detected, it is determined that the external control power supply is normal, and the external control power supply test is completed;

[0060] Receive the dry contact detection signal input from the outside, and after detecting a high level through the CH1 pin, control the dry contact acquisition channel circuit to complete the dry contact signal acquisition.

[0061] In specific implementation, the embodiment of the present application can provide the external control power supply detection function circuit for, when the external control power supply DC24V input is normal, after passing through the current limiting resistor, the input end of the photoMOS relay is turned on, the internal light-emitting diode is lit, and the output end of the photoMOS relay is turned on, so that after the micro control unit detects the change of the CHF_24V signal level from the initial low level to the high level, the micro control unit performs logical operations through software inside to realize the external control power supply detection function.

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

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

[0064] The redundant power supply circuit includes a bus diode, an overvoltage, undervoltage, overcurrent and surge protection circuit, an isolation DCDC, and a photo 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 the 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 optical MOS relay U7, an optical MOS relay U8, a reverse protection diode D11, and a transient voltage suppressor diode TVS2.

[0068] The dry contact acquisition module and channel self-test system provided in the embodiments of the present application introduce a self-test circuit composed of an optical MOS relay. The microcontroller unit controls the self-test of the acquisition channel before connecting to the external dry contact, thereby 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 to ensure the normal operation of the channel under the condition of external control power failure. Finally, reverse protection diodes, TVS tubes and other protective devices are set on the acquisition channel, and a dual current-limiting resistor configuration is used on the channel to prevent the external control power input to the dry contact acquisition channel from damaging the subsequent optical MOS relay when a single resistor is short-circuited, thereby preventing the dry contact acquisition channel from operating normally.

[0069] The dry contact acquisition module and channel self-test system provided in the embodiments of the present application effectively solve the problem that the lack of self-test will make it impossible to locate the approximate position 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 start 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 the embodiments of the present application effectively solve the problem of misjudging the external lack of switching signal input, resulting in the inability to timely detect changes in the external system environment. The current-limiting resistor is not connected in parallel with the optocoupler but is connected in series with 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 output terminal connection method of the optical MOS relay. The output terminal current-limiting resistor and the switching status detection signal are connected to both sides of the output terminal of the optical MOS relay, eliminating the Schmidt inverter and thus achieving the same switching value acquisition effect.

[0071] The system provided in the embodiment of the present application is described in detail below with reference to a specific circuit diagram.

[0072] All components of the dry contact acquisition module and channel self-test system provided in the embodiment of the present application follow the domestic design, and all components are domestic devices. 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 shown.

[0073] The power detection circuit of the present 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 a photoMOS relay. 24VIN_F is the combined DC24V voltage, and MCU_3.3V is the module's internal DC3.3V voltage.

[0074] The operation process of the acquisition path can be summarized as follows: Under normal conditions of the external control power supply DC24V input, after passing through the current limiting resistor, the input end of the photoMOS relay is turned on, the internal light-emitting diode lights up, and then the output end of the photoMOS relay is turned on. Since the output end already has a DC3.3V power supply, the microcontroller unit detects the change of the CHF_24V signal level from the initial low level to the high level. The microcontroller unit performs logical operations through software inside the microcontroller unit to realize the external control power supply detection function.

[0075] The redundant control power supply process of the acquisition channel generated inside the dry contact acquisition module and the detailed circuit of the power supply switching inside the module provided in the embodiment of the present application are as follows: Figure 3 and Figure 4 shown.

[0076] Figure 3 In the module, 24V1 and 24V2 are two redundant external input DC power supplies for the module, which form the 24V DC power supply inside the module after passing through the bus diode; 24V forms VCC_24V after passing through the overvoltage, undervoltage and overcurrent surge protection circuit formed by the hot-swappable chip; VCC_24V forms TEST_24V after passing through the isolated DC / DC module. Whether the isolated DC / DC module is turned on or off 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 control the DC / DC enable, and then outputs TEST_24V; TEST_24V passes through the Figure 4 The photoMOS relay and transistor switch protection circuit shown in the figure form 24VIN_F, which is used as the control power supply of the acquisition channel.

[0077] Figure 4In addition to being the DC / DC enable control pin, the PWR_CTR pin also serves as the enable pin for NPN transistor Q3. This means it controls channel power switching when no external control power is available. By outputting a high level via the microcontroller's GPIO pin, the module's internally converted 24VIN_F is enabled as the control power supply for the acquisition channels. R13 is a 4.7KΩ resistor, R14 is a 1KΩ resistor, and R15 is a 10KΩ resistor. Q3 is an NPN transistor, D10 and D11 are protection diodes, and U6 is a photoMOS relay.

[0078] The control process is summarized as follows: the high-level signal from the PWR_CTR pin turns on the NPN transistor Q3 after passing through resistors R14 and R15. The input end of the photoMOS relay has a VCC_24V DC power supply. VCC_24V passes through the current-limiting resistor R13. The photoMOS relay U6 and the NPN transistor Q3 are connected to the internal power ground. The input end of U6 is turned on, and the internal light-emitting diode lights up, causing its output end to turn on. Finally, the TEST_24V converted by the isolated DC / DC passes through the output end of the photoMOS relay to form 24VIN_F as the control power supply for the acquisition channel.

[0079] Figure 5 This is the detailed circuit of the dry contact acquisition channel for self-test, where: R16 uses a 3.3KΩ resistor, R17 uses a 2.2KΩ resistor, R18 uses a 10KΩ resistor, R19 uses a 0Ω resistor, R20 uses a 330Ω resistor, R21 uses a 1KΩ resistor, R22 uses a 10KΩ resistor, C3 / C5 use 0.1uF / 50V filter capacitors, C4 uses a 15pF / 100V capacitor, Q4 is an NPN transistor, U7 / U8 are photoMOS 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. When the external dry contact input is normal, that is, IN1 and IN2 are closed, the acquisition channel circuit is formed by the control power supply 24VIN_F, R16, U7, R17, D11, and the digital ground of the external control power supply. The U7 input terminal is turned on, the internal light-emitting diode lights up, and its output terminal is turned on. The CH1 pin of the microcontroller detects the change in level from the initial low level to the high level. The microcontroller can then identify the external switch input through software, and then issue an early warning of abnormal working conditions in the control site.

[0081] The acquisition channel self-test function is controlled by the MCU's CHK1 pin. When CHK1 outputs a high level, NPN transistor Q4 conducts, and the MCU_3.3V DC power supply is connected to the input of photoMOS relay U8. The MCU_3.3V passes through current-limiting resistor R20, and then to the internal power ground of photoMOS relay U8 and NPN transistor Q4. When U8's input is turned on, the internal LED illuminates, turning on its output. Therefore, the acquisition channel circuit forms a loop consisting of the control power supply 24VIN_F, R16, U7, R17, D11, R19, U8, and the external control power supply's digital ground. When U7's input is turned on, the internal LED illuminates, turning on its output. The MCU's CH1 pin detects a change in level from an initial low to a high level, completing the channel self-test. Software within the MCU controls the timing of CHK1 outputs, thus enabling the scheduled channel self-test function.

[0082] In addition, if the external IN1 mistakenly inputs a DC24V or DC48V voltage signal, due to the unidirectional conductivity of the diode D11 on the acquisition channel, no current loop will be formed, thereby protecting the subsequent circuit from damage.

[0083] The system provided in the embodiment of the present application introduces Figure 4 The redundant power supply circuit shown can realize the effective conversion 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 the normal operation of the dry contact signal acquisition channel.

[0084] At the same time, the hardware selection follows the domestically produced design, using optical MOS relays, TVS tubes and reverse protection diodes as isolation and protection devices on the dry contact signal acquisition path, and adopting dual-resistor current limiting to protect the microcontroller unit and subsequent devices in the event of abnormal external control power input or a resistor short circuit.

[0085] In addition, a channel self-test circuit is introduced. When there is no external control power input, the processor controls the operation of the self-test circuit and uses the output of the dry contact signal acquisition circuit as the sampling signal, thereby achieving the purpose of detecting whether the working status of the entire circuit is normal or not. 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 by this application can, in the event of an external control power input failure, control the operation of the optical MOS relay and transistor switch protection circuit through the GPIO pin of the microcontroller unit inside the module, thereby outputting the control power for the acquisition channel. In addition to being able to acquire external dry contact input signals, it also has reverse protection and short-circuit protection functions, and can prevent damage to devices on the acquisition path when the external input is an active contact. It can detect whether the working status of the channel is normal before the external dry contact signal enters, make a preliminary judgment and analysis, and make timely adjustments based on abnormal conditions to ensure the accuracy of external signal acquisition.

[0087] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0088] Through the description of the above embodiments, it can be seen that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments or certain parts of the embodiments of the present application.

[0089] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on 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. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A dry contact acquisition module and channel self-test system, characterized in that: It includes an external control power supply detection function circuit, a dry contact acquisition channel circuit, an acquisition channel self-test circuit, a redundant power supply circuit and a micro control unit; The microcontroller unit is used to perform the following operations: After determining that the module to which the dry contact acquisition channel circuit belongs is powered on and started normally, the redundant power supply circuit is controlled to form the 24VIN_F power supply of the dry contact acquisition channel circuit through the PWR_CTR pin outputting a high level; Outputting a high level via the CHK1 pin enables the self-test circuit of the acquisition channel; Determine whether the CH1 pin detects a high level; If it is determined that no high level is detected, it is determined that the dry contact acquisition channel circuit is abnormal and a prompt message is generated; If a high level is detected, it is determined that the dry contact acquisition channel circuit has completed the channel self-test normally; After determining that the channel self-test is completed, the redundant power supply circuit is controlled to be turned off by outputting a low level through the PWR_CTR pin, and the acquisition channel self-test circuit is controlled to be turned off by outputting a low level through the CHK1 pin; After confirming the input of external control power supply, controlling the operation of the dry contact acquisition channel circuit; Determine whether the CHF_24V pin and the CH1 pin are both detected to be high level; If it is determined that a high level is not detected, it is determined that the external control power input is abnormal, and it is determined whether the external control power has been replaced; after determining that the external control power has been replaced, the replaced external control power is used as the input of the external control power to provide 24VIN_F power to the dry contact acquisition channel circuit; after determining that the external control power has not been replaced, the abnormal external control power is disconnected, and the PWR_CTR pin is controlled to output a high level, so that the redundant power supply circuit is enabled to provide 24VIN_F power to the dry contact acquisition channel circuit; After confirming that a high level is detected, it is determined that the external control power supply is normal, and the external control power supply test is completed; Receive the dry contact detection signal input from the outside, and after detecting a high level through the CH1 pin, control 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 function circuit is used to, when the external control power supply DC24V input is normal, turn on the input end of the photoMOS relay after passing through the current limiting resistor, and light up the internal light-emitting diode to turn on the output end of the photoMOS relay. After the microcontroller detects that the signal level of CHF_24V changes from an initial low level to a high level, the microcontroller performs logical operations through software inside the microcontroller to implement the external control power supply detection function.

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

4. The dry contact acquisition module and channel self-test system according to claim 1, characterized in that: The redundant power supply circuit includes a bus diode, an overvoltage, undervoltage, overcurrent and surge protection circuit, an isolation DCDC, and a photo MOS relay and transistor switch protection circuit.

5. The dry contact acquisition module and channel self-test system according to claim 4, 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.

6. 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 the optical MOS relay U7 and IN1 / IN2; IN1 and IN2 are the two ends of the dry contact input respectively.

7. The dry contact acquisition module and channel self-test system according to claim 6, 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 optical MOS relay U7, an optical MOS relay U8, a reverse protection diode D11, and a transient voltage suppression diode TVS2.

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