Switching value output circuit with contact feedback, output method and system

Abstract

The invention discloses an on-off output circuit with contact feedback, an output method and a system, and relates to the technical field of industrial control, and the key points of the technical scheme are as follows: an output port of a processor is connected with a first port of a primary side of a relay, and is used for providing a driving signal for the closing and opening of the relay; a secondary side second port of the relay is connected with the feedback unit, serves as an input port of the feedback unit and is used for providing conduction current for the feedback unit; a first output port of the feedback unit is connected with an input port of the processor and is used for feeding back the conduction condition of the secondary side of the relay to the processor; and the processor is also used for receiving the feedback signal generated by the feedback unit and judging the fault condition of the switching value output circuit according to the level states of the driving signal and the feedback signal. The problem that a switching value output circuit provided in the prior art is insufficient in reliability is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of industrial control technology, more particularly, it relates to a switching quantity output circuit with contact feedback, an output method and a system. BACKGROUND

[0002] The switching quantity output circuit is widely used in industrial manufacturing process, which provides dry contact or wet contact switching quantity signal for field devices. In some occasions with high reliability requirements, the switching quantity module is usually required to have contact feedback or diagnosis function. For example, in a nuclear safety DCS system, the switching quantity output will participate in the stop logic voting, priority logic input judgment and other links, so the switching quantity output link must be safe and reliable, and processor output abnormalities, relay failures and other problems may cause switching quantity output malfunction or refusal, which may cause serious consequences. Therefore, the action state of the relay in the switching quantity circuit needs to be clearly fed back. If no feedback is obtained within the specified time after the action command is issued, it can be judged that there is an open circuit, short circuit, device failure and other faults in the switching quantity output channel link, so as to change the execution logic of the system in time.

[0003] The contact feedback and diagnosis of the existing switching quantity module are usually realized by three ways:

[0004] 1. Inject current through the secondary side of the relay by using an isolation power supply, and use an isolator to sample back. This brings the problem that the relay has polarity, and the reverse connection of the device power supply may cause circuit failure. In addition, in the scene of multi-channel isolated output, multiple DC / DC on-board isolation power supplies need to be added on the board card, which greatly increases the power consumption of the board card, and when densely arranged in a nuclear safety level DCS cabinet, it will bring difficulties to the heat dissipation of the whole system.

[0005] 2. Use a Hall sensor as a feedback device to sample the current of the relay output side. However, this scheme can only be used for contact diagnosis of large current switching quantity signals above 1A. In the scene of DCS, the switching quantity signal is mainly in the order of milliamperes. Due to the limitation of sensitivity, it is difficult for the Hall sensor to accurately detect the change of the milliamperes current signal. In addition, using a Hall sensor also needs to add an analog-to-digital converter on the secondary side for sampling, so this scheme increases the cost of the circuit while reducing the reliability of the overall circuit.

[0006] 3. Parallel a high-sensitivity relay to the load end as a feedback device, and introduce the field power supply ground into the board card. In this scheme, the high-sensitivity relay has high cost, and most DCSs in field engineering applications do not support introducing the field power supply ground into the board card because the switching quantity output is two-wire system.

[0007] In summary, it can be seen that there is a problem of insufficient reliability in the switching quantity output circuit provided by the existing technology. SUMMARY

[0008] The present application aims to provide a switch output circuit with contact feedback, output method and system, which solves the problem of insufficient reliability of the switch output circuit provided by the prior art.

[0009] The above technical purposes of the present application are achieved by the following technical solutions:

[0010] In a first aspect of the present application, a switch output circuit with contact feedback is provided, which is installed on a board card, and the circuit comprises a processor, a relay and a feedback unit;

[0011] The output port of the processor is connected with the primary side first port of the relay, for providing a driving signal for the closing and opening of the relay;

[0012] The secondary side second port of the relay is connected with the feedback unit as an input port of the feedback unit, for providing a conduction current for the feedback unit;

[0013] The first output port of the feedback unit is connected with the input port of the processor, for feeding back the conduction condition of the secondary side of the relay to the processor;

[0014] The processor is also used for receiving the feedback signal generated by the feedback unit, and judging the fault condition of the switch output circuit according to the level state of the driving signal and the feedback signal;

[0015] The secondary side first port of the relay is connected with the positive contact of the board card, and the second output port of the feedback unit is connected with the negative contact of the board card, for driving the load device.

[0016] In an implementation scheme, the feedback unit comprises an optoelectronic coupler, a transistor, a diode, a first resistor and a second resistor;

[0017] The first port of the primary side of the optoelectronic coupler is connected with the collector of the transistor, the second port of the primary side of the first optoelectronic coupler is connected with the first port of the first resistor and the second resistor respectively, the second port of the second resistor is connected with the base of the transistor, and the second port of the first resistor is connected with the emitter of the transistor;

[0018] The collector of the transistor is connected with the secondary side second port of the relay, and the emitter of the transistor is connected with the negative contact of the board card;

[0019] The cathode of the diode is connected with the collector of the transistor, and the anode of the diode is connected with the emitter of the transistor.

[0020] In an implementation scheme, the first port of the primary side of the optoelectronic coupler is a positive terminal, and the second port of the primary side is a negative terminal.

[0021] In one implementation, the primary side of the optocoupler is a diode, and the secondary side of the optocoupler is a phototransistor.

[0022] In one implementation, a resistor is connected in parallel to the collector of the phototransistor, and the emitter of the phototransistor is grounded.

[0023] In one implementation, the second port of the primary side of the relay is grounded or connected to the negative terminal of the drive signal.

[0024] In one implementation, the relay is any one of an electromagnetic relay, a PHOTOMOS relay, a field-effect transistor, a thyristor, and a transistor.

[0025] In a second aspect, the present invention provides a method for switch output with contact feedback, applied to a switch output circuit with contact feedback as provided in the first aspect of the present invention, the method comprising:

[0026] Based on the circuit structure within the feedback unit, construct the Kirchhoff equations within the feedback unit;

[0027] Based on Kirchhoff's equations, the first equation for the current flowing through the optocoupler is determined. The first equation is then optimized to determine the second equation that minimizes the on-state voltage drop loss of the switching contacts.

[0028] The resistance value of the first resistor is selected according to the second equation so that the current when the optocoupler is normally conducting is stable within the range of 1mA to 20mA.

[0029] In one implementation, the Kirchhoff equations include:

[0030] I1*R1=I b *R2+U be ;

[0031] I b *H fe =I c ;

[0032] I op +I c =I o ;

[0033] I1+I b =I op Among them, I op For the current flowing through the optocoupler, U be H is the potential difference between the base and emitter of a transistor. fe I is the DC amplification factor of the transistor. bI1 is the current flowing through the base of the transistor, and I2 is the current flowing through the first resistor. o I is the total current in the loop. c R1 is the resistance of the first resistor, and R2 is the resistance of the second resistor.

[0034] In one implementation, the expression for the first equation, the current equation, is:

[0035] In one implementation, the first equation is optimized to determine a second equation that minimizes the on-state voltage drop loss of the switching contact. Specifically, the resistance of the second resistor is reduced to 0, resulting in the second equation. The expression for the second equation is:

[0036] In a third aspect, the present invention provides a nuclear safety DCS system, including a switch output circuit with contact feedback as provided in the first aspect of the present invention.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This invention, while realizing the output of switch signals, uses the current in the relay output circuit as the driving signal for the optocoupler in the feedback unit, so that the optocoupler is triggered in the forward direction, realizing feedback on the contact action. Combined with the processor driving signal, it can determine whether there are contact faults, driving abnormalities, power reversal or other faults in the field drive output circuit. It can be seen that this invention uses the signal of the optocoupler for contact feedback, has strong current adaptability, and has high engineering value. Attached Figure Description

[0039] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0040] Figure 1 A schematic diagram of a switch output circuit with contact feedback provided in an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the relay secondary current flow provided in an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of an embodiment of a switch output circuit with contact feedback provided by an embodiment of the present invention.

[0043] Figure labels and descriptions:

[0044] R1, first resistor; R2, second resistor; Q3, transistor; Q2, optocoupler; Q1, relay; D1, diode. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0046] It should be noted that the terms "comprising" or "may include" used in the various embodiments of this application indicate the presence of the claimed function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in the various embodiments of this application, the terms "comprising," "having," and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0047] It should be understood that terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0048] Figure 1 This is a schematic diagram of a switch output circuit with contact feedback provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the circuit, mounted on a board, includes a processor, a relay Q1, and a feedback unit. The processor's output port is connected to the primary side of the relay Q1, providing a drive signal for the relay Q1 to close and open. The secondary side of the relay Q1 is connected to the feedback unit, serving as its input port and providing conduction current. The first output port of the feedback unit is connected to the processor's input port, providing feedback to the processor on the conduction status of the secondary side of the relay Q1. The processor also receives feedback signals generated by the feedback unit and determines the fault status of the switch output circuit based on the level states of the drive signal and the feedback signal. The primary side of the relay Q1 is connected to the board's positive contact, and the second output port of the feedback unit is connected to the board's negative contact, used to drive the load device.

[0049] In this embodiment, the processor includes, but is not limited to, processors such as CPLD, ARM, and FPGA. The relay Q1 includes, but is not limited to, devices with switching characteristics such as PHOTOMOS relay Q1, electromagnetic relay Q1, and field-effect transistors.

[0050] like Figure 1 As shown, the processor's I / O port is connected to the first port of the primary side of relay Q1 via a current-limiting resistor. The second port of relay Q1 is grounded or connected to the negative terminal of the drive signal. The first port of the secondary side of relay Q1 is connected to the first port of the output contact on the board side. At the same time, the second port of the secondary side of relay Q1 is connected to the first port of the feedback unit. The second port of the feedback unit is connected in series with the second port of the output contact on the board side, i.e., the negative contact of the board.

[0051] The board provided in this embodiment is a circuit board. In other words, the entire circuit is encapsulated on the circuit board, which has an output terminal, thereby providing dry or wet contact switching signals to the load device on the field side.

[0052] In some embodiments, the feedback unit includes an optocoupler Q2, a transistor Q3, a diode D1, a first resistor R1, and a second resistor R2; the first port of the primary side of the optocoupler Q2 is connected to the collector of the transistor Q3, the second port of the primary side of the optocoupler Q2 is connected to the first ports of the first resistor R1 and the second resistor R2 respectively, the second port of the second resistor R2 is connected to the base of the transistor Q3, and the second port of the first resistor R1 is connected to the emitter of the transistor Q3; the collector of the transistor Q3 is connected to the second port of the secondary side of the relay Q1, and the emitter of the transistor Q3 is connected to the negative contact of the board; the cathode of the diode D1 is connected to the collector of the transistor Q3, and the anode of the diode D1 is connected to the emitter of the transistor Q3.

[0053] Specifically, an optocoupler (Q2) is a device that converts electrical signals into optical signals and then back into electrical signals. It achieves electrical isolation between input and output and is widely used in circuit isolation, signal transmission, noise suppression, and other fields.

[0054] In this embodiment, the emitter of optocoupler Q2 is connected to the base of transistor Q3. The purpose is to stabilize the voltage at the Vbe terminal of transistor Q3 to form a stable drive current, enabling the secondary side of relay Q1 to establish a stable contact feedback signal when current is applied. The stable drive current provided in this solution refers to the stable current flowing through optocoupler Q2, not the stable output switching quantity. Therefore, this embodiment ensures that the operating conditions and current magnitude of the switching quantity do not affect the stability of optocoupler Q2.

[0055] The transistor provided in this embodiment is an NPN type. An NPN transistor is a type of bipolar junction transistor (BJT) and is the most commonly used type. An NPN transistor is a semiconductor device based on the principle of current control, possessing both amplification and switching functions. Its core principle lies in using a small base current to control a large collector current; the amplification capability is determined by the current amplification factor.

[0056] In some embodiments, the first port of the primary side of the optocoupler Q2 is the positive terminal, and the second port of the primary side is the negative terminal. Specifically, the ports have positive and negative attributes; furthermore, this is common knowledge to those skilled in the art, and will not be described in detail in this embodiment.

[0057] In some embodiments, the primary side of optocoupler Q2 is diode D1, and the secondary side of optocoupler Q2 is phototransistor Q3.

[0058] Specifically, the optocoupler Q2 mainly consists of two parts: the light-emitting end, which is usually an infrared LED (light-emitting diode D1), converting the electrical signal into a light signal; and the light-receiving end, which is usually a phototransistor Q3, a photodarlington transistor, or a photocontrolled thyristor, converting the light signal back into an electrical signal. Both are encapsulated in an opaque housing, achieving complete electrical isolation between the input and output.

[0059] This is existing technology, and this embodiment only provides a brief introduction to the optocoupler Q2.

[0060] In some embodiments, a resistor is connected in parallel to the collector of the phototransistor Q3, and the emitter of the phototransistor Q3 is grounded.

[0061] In some embodiments, the primary side second port of the relay Q1 is grounded or connected to the negative terminal of the drive signal.

[0062] In the switch output circuit described above, its specific working principle is as follows: The processor provides an output drive signal to control the closing and opening of relay Q1. When the secondary side of relay Q1 is closed, the secondary circuit is turned on to generate current, which drives the load. At the same time, the optocoupler Q2 in the feedback unit is excited by the circuit current, which will turn on the secondary side of optocoupler Q2. After being processed by pull-up and pull-down, the secondary side of optocoupler Q2 is connected to the processor's IO pin, thereby feeding back the conduction status of the secondary side of relay Q1 to the processor in the form of high and low levels. The processor determines whether there is a drive and whether it is normal based on the feedback signal.

[0063] The core of this invention lies in the fact that the current conduction current of the optocoupler Q2 is typically 1mA-20mA. If only the optocoupler Q2 is used as the feedback device, the current in the secondary circuit is limited by the optocoupler's conduction current, allowing only 1mA-20mA to pass through, which cannot meet the requirements of engineering applications. To ensure that the contacts conduct normally without burning out the optocoupler Q2 when the load current varies over a wide range of 1mA-3A, while also ensuring normal feedback function, this invention uses transistor Q3 for adaptive current shunting, so that the current on the optocoupler Q2 remains stable within the 1mA-20mA range, regardless of large variations in the load current.

[0064] like Figure 2 As shown, to ensure that the optocoupler Q2Q2 remains stable within the current range, this embodiment provides a switching output method with contact feedback, applied to a switching output circuit with contact feedback as described above. The circuit includes a processor, a relay Q1, and a feedback unit. The processor's output port is connected to the first port of the primary side of the relay Q1, providing a drive signal for the closing and opening of the relay Q1. The second port of the secondary side of the relay Q1 is connected to the feedback unit, serving as the input port of the feedback unit, providing conduction current to the feedback unit. The first output port of the feedback unit is connected to the processor's input port, providing feedback to the processor on the conduction status of the secondary side of the relay Q1. The processor also receives the feedback signal generated by the feedback unit and determines the fault status of the switching output circuit based on the level states of the drive signal and the feedback signal. The first port of the secondary side of the relay Q1 is connected to the positive contact of the board, and the second output port of the feedback unit is connected to the negative contact of the board, used to drive the load device. The feedback unit includes an optocoupler Q2, a transistor Q3, a diode D1, a first resistor R1, and a second resistor R2. The first port of the primary winding of the optocoupler Q2 is connected to the collector of the transistor Q3. The second port of the primary winding of the optocoupler Q2 is connected to the first ports of the first and second resistors R1 and R2, respectively. The second port of the second resistor R2 is connected to the base of the transistor Q3. The second port of the first resistor R1 is connected to the emitter of the transistor Q3. The collector of the transistor Q3 is connected to the second port of the secondary winding of the relay Q1, and the emitter of the transistor Q3 is connected to the negative contact of the board. The cathode of the diode D1 is connected to the collector of the transistor Q3, and the anode of the diode D1 is connected to the emitter of the transistor Q3. The first port of the primary winding of the optocoupler Q2 is the positive terminal, and the second port is the negative terminal. The primary winding of the optocoupler Q2 is diode D1, and the secondary winding of the optocoupler Q2 is phototransistor Q3. A resistor is connected in parallel to the collector of phototransistor Q3, and the emitter of phototransistor Q3 is grounded. The second port of the primary side of relay Q1 is grounded or connected to the negative terminal of the drive signal.

[0065] The specific working principle is as follows: The processor provides an output drive signal to control the closing and opening of relay Q1. When the secondary side of relay Q1 is closed, the secondary circuit is turned on to generate current, which drives the load. At the same time, the optocoupler Q2 in the feedback unit is excited by the circuit current, which will turn on the secondary side of optocoupler Q2. After being pulled up and pulled down, the secondary side of optocoupler Q2 is connected to the processor's I / O pin, thereby feeding back the conduction status of the secondary side of relay Q1 to the processor in the form of high and low levels. The processor determines whether there is a drive and whether it is normal based on the feedback signal.

[0066] The switching output method includes: constructing Kirchhoff's equations within the feedback unit based on the circuit structure within the feedback unit; determining the first equation for the current flowing through the optocoupler Q2 based on the Kirchhoff's equations; optimizing the first equation to determine the second equation that minimizes the conduction voltage drop loss of the switching contact; and selecting the resistance value of the first resistor R1 based on the second equation to stabilize the current of the optocoupler Q2 during normal conduction within the range of 1mA to 20mA.

[0067] Specifically, Kirchhoff's equations include the following four expressions:

[0068] I1*R1=I b *R2+U be ;

[0069] I b *H fe =I c ;

[0070] I op +I c =I o ;

[0071] I1+I b =I op Among them, I op For the current flowing through the optocoupler, U be H is the potential difference between the base and emitter of a transistor. fe I is the DC amplification factor of the transistor. b I1 is the current flowing through the base of the transistor, and I2 is the current flowing through the first resistor. o I is the total current in the loop. c R1 is the resistance of the first resistor, and R2 is the resistance of the second resistor.

[0072] In some embodiments, the expression for the first equation, the current equation, is:

[0073] In some embodiments, the first equation is optimized to determine a second equation that minimizes the on-state voltage drop loss of the switching contact. Specifically, the resistance of the second resistor is reduced to 0 to obtain the second equation; wherein, the expression of the second equation is:

[0074] In this embodiment, determining the Kirchhoff equation of the feedback unit based on Kirchhoff's current law is a conventional technique for those skilled in the art, and will not be described in detail here.

[0075] Depend on It can be seen that in the circuit structure of the feedback unit, the current I flowing through the optocoupler is... op Depends on the total loop current I o The DC amplification factor H of the transistor fe The voltage difference U between the base and emitter of a transistor be The first resistor. Where U be H fe I is an inherent parameter of the transistor. o This can be obtained from specific application scenarios. When the H of the transistor... fe When the parameters are sufficiently large (100 to 300 times), the current I1 flowing through the optocoupler and the input current I o It exhibits a very weak linear correlation; its current primarily depends on the voltage difference U between the base and emitter of the transistor. be And the value of the first resistor. Based on the transistor's U... be By selecting an appropriate value for the first resistor, the current during normal conduction of the optocoupler can be stabilized in the range of 1mA to 20mA. At the same time, the current exceeding this range will be shunted through the transistor, thereby realizing the contact feedback function within a larger current range.

[0076] Based on the switch output circuit and output method described above, this application provides the following specific examples:

[0077] The processor is an FPGA, and relay Q1 is a PHOTOMOS relay. The FPGA outputs a drive control signal through the I / O port, which drives the PHOTOMOS relay after current limiting by a resistor. In the feedback unit, the first resistor R1 is 180 ohms, the second resistor R2 is 0 ohms, the transistor Q3 is an NPN transistor 2SD1767 with a DC amplification factor Hfe of approximately 300 times, and the optocoupler Q2 is an OR-3H7. According to the working principle described above, when the loop current is 1mA to 3A, the primary current of optocoupler Q2 is approximately 5mA to 15mA, which meets the normal operating current range of optocoupler Q2.

[0078] When the secondary side of PHOTOMOS relay Q1 is closed, the secondary circuit conducts, generating current to drive the load. Simultaneously, the optocoupler Q2 in the feedback unit is excited by the circuit current, causing its secondary side to conduct. After being pulled up and processed, the secondary side of optocoupler Q2 is connected to the processor's I / O pin. When optocoupler Q2 is on, the feedback input is low; when optocoupler Q2 is off, the feedback input is high, thus feeding back the conduction status of the secondary side of relay Q1 to the processor. The processor uses the feedback signal to determine whether the drive is functioning correctly. The processor combines the output drive signal and the feedback signal to judge the fault status of the contacts and circuit. 1 represents a high level, and 0 represents a low level. The corresponding drive and feedback signals and their corresponding fault types are shown in Table 1.

[0079] Table 1 Truth Table for Fault Diagnosis Types of Drive Signals and Feedback Signals

[0080] Output drive signal Receive feedback signal Fault determination 1 0 No fault 1 1 Output drive fault / secondary loop open / opto failure / power reverse 0 1 No fault 0 0 Primary drive fault / relay secondary breakdown or sticking

[0081] This invention also provides a nuclear safety DCS system, including a switch output circuit with contact feedback as described in the above embodiments.

[0082] Specifically, digital output circuits are widely used in industrial manufacturing processes to provide dry or wet contact digital signals to field devices. In applications with high reliability requirements, digital modules are typically required to have contact feedback or diagnostic functions. For example, in DCS systems, where relay boards serve as output drivers, digital outputs participate in stop logic voting and priority logic input judgment. Therefore, the digital output circuit must be safe and reliable. Abnormal processor outputs or relay failures can cause malfunctions or failures in digital output, leading to serious consequences. Therefore, clear feedback on the relay operation status in the digital circuit is necessary. If feedback is not received within a specified time after the action command is issued, it can be determined that there is an open circuit, short circuit, or device failure in the digital output channel, allowing for timely adjustments to the system's execution logic.

[0083] After adopting the switching output circuit provided in this embodiment, while realizing the output of switching signals, the current in the relay output circuit is used as the driving signal for the optocoupler in the feedback unit, causing the optocoupler to be forward triggered, realizing feedback on the contact action status. Combined with the processor driving signal, it is possible to determine whether there are faults such as contact failure, driving abnormality, or reverse power connection in the field drive output circuit. Compared with the prior art, the circuit provided by this invention is simple and reliable, does not require field grounding, and compared with the Hall sensor used as the feedback element in the prior art, the optocoupler used in this invention is lower in cost and has stronger current adaptability. It can be applied to the driving and status feedback of switching output signals in the contact capacity range of 1mA / 24V-3A / 24V, and has high engineering value.

[0084] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0085] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0086] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0087] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific 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 should be included within the scope of protection of the present invention.

Claims

1. A switch output circuit with contact feedback, mounted on a circuit board, characterized in that, The circuit includes a processor, relays, and a feedback unit; The processor's output port is connected to the primary side first port of the relay, and is used to provide drive signals for the relay's closing and opening. The second port of the relay is connected to the feedback unit and serves as the input port of the feedback unit, used to provide conduction current to the feedback unit; The first output port of the feedback unit is connected to the input port of the processor and is used to provide feedback to the processor on the conduction status of the relay secondary side; The processor is also used to receive feedback signals generated by the feedback unit and to determine the fault status of the switch output circuit based on the level states of the drive signal and the feedback signal. The relay's secondary side first port is connected to the board's positive contact, and the feedback unit's second output port is connected to the board's negative contact, used to drive the load device.

2. The switching output circuit with contact feedback according to claim 1, characterized in that, The feedback unit includes an optocoupler, a transistor, a diode, a first resistor, and a second resistor; The first port of the primary side of the optocoupler is connected to the collector of the transistor, the second port of the primary side of the first optocoupler is connected to the first port of the first resistor and the first port of the second resistor respectively, the second port of the second resistor is connected to the base of the transistor, and the second port of the first resistor is connected to the emitter of the transistor. The collector of the transistor is connected to the second secondary port of the relay, and the emitter of the transistor is connected to the negative contact of the board. The cathode of the diode is connected to the collector of the transistor, and the anode of the diode is connected to the emitter of the transistor.

3. A switching output circuit with contact feedback according to claim 2, characterized in that, The first port of the primary side of the optocoupler is the positive terminal, and the second port of the primary side is the negative terminal.

4. A switching output circuit with contact feedback according to claim 2, characterized in that, The primary side of the optocoupler is a diode, and the secondary side of the optocoupler is a phototransistor.

5. A switching output circuit with contact feedback according to claim 4, characterized in that, A resistor is connected in parallel to the collector of the phototransistor, and the emitter of the phototransistor is grounded.

6. A switch output circuit with contact feedback according to claim 1, characterized in that, The primary side second port of the relay is grounded or connected to the negative terminal of the drive signal.

7. A switching output circuit with contact feedback according to claim 1, characterized in that, The relay can be any one of an electromagnetic relay, a PHOTOMOS relay, a field-effect transistor, a thyristor, or a transistor.

8. A method for providing switch output with contact feedback, applied to a switch output circuit with contact feedback as described in any one of claims 1 to 7, characterized in that, The methods include: Based on the circuit structure within the feedback unit, construct the Kirchhoff equations within the feedback unit; Based on Kirchhoff's equations, the first equation for the current flowing through the optocoupler is determined. The first equation is then optimized to determine the second equation that minimizes the on-state voltage drop loss of the switching contacts. The resistance value of the first resistor is selected according to the second equation so that the current when the optocoupler is normally conducting is stable within the range of 1mA to 20mA.

9. A switch output method with contact feedback according to claim 8, characterized in that, The Kirchhoff equations include: I1*R1=I b *R2+U be ; I b *H fe =I c ; I op +I c =I o ; I1+I b =I op Among them, I op For the current flowing through the optocoupler, U be H is the potential difference between the base and emitter of a transistor. fe I is the DC amplification factor of the transistor. b I1 is the current flowing through the base of the transistor, and I2 is the current flowing through the first resistor. o I is the total current in the loop. c R1 is the resistance of the first resistor, and R2 is the resistance of the second resistor.

10. A switch output method with contact feedback according to claim 9, characterized in that, The expression for the first equation, the current equation, is:

11. A method for switch output with contact feedback according to claim 10, characterized in that, The first equation is optimized to determine the second equation that minimizes the on-state voltage drop loss of the switching contacts, specifically: By reducing the resistance of the second resistor to 0, we obtain the second equation; the expression for the second equation is:

12. A nuclear safety DCS system, characterized in that, Includes a switch output circuit with contact feedback as described in claims 1 to 7.

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