A matrix expansion method for realizing multi-point input and output of a controller

Abstract

The present invention is a matrix expansion method for realizing multi-point input and output of a controller, including input expansion and output expansion; in the output expansion, loads are provided between the output terminals of each controller in the rows and columns of the matrix expansion output circuit, and each load is respectively connected through an isolation unit and the output terminal of the controller located on the column of the matrix expansion output circuit and connected to the load; the isolation unit is a diode, the positive pole of the diode is connected to the load, and the negative pole is connected to the controller output terminal. The parasitic loop generated by cutting off the electromagnetic interference between the loads through the isolation unit is avoided, so that when the loads in different rows and columns of the output circuit are simultaneously turned on, the load at the intersection of the corresponding row and column is not affected, the reliability of the input and output expansion is improved, and each output point can stably drive the load.

Description

Technical Field

[0001] The present invention belongs to the technical field of controller I / O port expansion, and specifically relates to a matrix expansion method for realizing multi-point input and output of a controller. Background Art

[0002] With the diversification and complexity of controlled objects, the demand for the number of I / O ports in control systems is also increasing. When using an already produced controller, it is not convenient and fast to increase the I / O ports. Programmable logic controllers (PLCs) play an important role in fields such as industrial automation and control systems. As the main control device, a PLC controller needs to be connected to various input signals (such as buttons, limit switches, toggle switches, contacts of relays, and other detection signals) and output devices (such as relay coils, contactor coils, solenoid valves, etc.) in the controlled object. In actual work, due to the limitation of the scale of the PLC controller application system, the number of input / output points of the PLC controller is usually insufficient and needs to be expanded.

[0003] Chinese Patent with publication number CN103064334B discloses a method and device for expanding the output points of a programmable logic controller (PLC). This method groups the output points of the programmable logic controller (PLC), and selects one output point of the programmable logic controller (PLC) in each group to correspond to one output point of the expansion device. It is required that one of the two output points in each group must be at a high level and the other must be at a low level, without considering the signal interference between two groups of output points, that is, there is signal crosstalk between different rows and different columns, resulting in unstable signal output. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a matrix expansion method for realizing multi-point input and output of a controller.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A matrix expansion method for realizing multi-point input and output of a controller, including input expansion and output expansion; characterized in that, assuming the input end of the controller is X and the output end is Y, the input end X includes the controller input end X 0 ~X m , the output end Y includes the controller output end Y 0 ~Y n , then the number of points for input expansion is m×n; assuming that the controller output ends for row expansion in output expansion are Y 0 ~Y i , and the controller output ends for column expansion are Y j ~Y nThen the number of expanded points output is i×(n - j), where i≠j; m, n, i, and j are all positive integers.

[0007] In the output expansion, loads are provided between the output terminals of each controller for the rows and columns of the matrix expansion output circuit. Each load is respectively connected through an isolation unit and the output terminal of the controller located on the column of the matrix expansion output circuit and connected to the load; the isolation unit is a diode, the positive pole of the diode is connected to the load, and the negative pole is connected to the output terminal of the controller. Assume that the output terminal of the controller for row - to - row expansion in the matrix expansion output circuit is Y 5 , and the output terminal of the controller for column - to - column expansion is Y 2 、Y 3 、Y 4 , then for the output terminal Y 5 , one end of the switch K 1 passes through the load L 1 and is connected to the positive pole of the diode D 1 , and the negative pole of the diode D 1 is connected to one end of the switch K 2 of the output terminal Y 4 ; for the output terminal Y 5 , one end of the switch K 1 passes through the load L 2 and is connected to the positive pole of the diode D 2 , and the negative pole of the diode D 2 is connected to one end of the switch K 3 of the output terminal Y 5 ; for the output terminal Y 5 , one end of the switch K 1 passes through the load L 3 and is connected to the positive pole of the diode D 3 , and the negative pole of the diode D 3 is connected to one end of the switch K 4 of the output terminal Y 6 ; for the output terminal Y 5 , the other end of the switch K 1 is connected to a high level, and the other ends of the switches K 4 ~K 6 are connected to a low level; when the output terminal Y 2 is conducting with Y 5 , the external current flow direction is Y 5 →K 1 →L 1 →D 1 →K 4 →Y 2 , at this time the load L 1 is in a high - level state, and other loads are in a low - level state, so that the load L 1 works.

[0008] When the input terminals X 0 ~X m of the controller are connected to pulse signals or digital signals, diodes are added to the matrix expansion input circuit. A diode is connected between each input terminal of the controller and the circuit output point connected to this input terminal of the controller. Except for the circuit output points connected to the input terminals of the controller in each row of the matrix expansion input circuit, a diode is connected between the remaining adjacent circuit output points; each intersection of the rows and columns of the matrix expansion input circuit is a circuit output point.

[0009] The switches K 1 、K 4 ~K 6 are all relays.

[0010] The controller is a PLC controller, an STM32 microcontroller or a 51 single-chip microcomputer.

[0011] When the controller is a PLC controller, input expansion uses ladder diagram program control, and a power-off delay time is set for the output terminals of the controller, that is, after scanning the output terminals of the controller in the first column of the matrix expansion output circuit, the output terminals of the remaining columns are sequentially extended for a period of time before starting to execute scanning. During this period, all output terminals of the controller are in a signal-free state.

[0012] The power-off delay time is 20 - 30 ms.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] 1. The present invention first adopts a circuit isolation technology in output expansion to eliminate the problem of unstable output voltage caused by signal crosstalk between different rows and columns in the matrix expansion output circuit, and has strong anti-interference ability; as Figure 3 shown, when the loads L 1 and L 6 in the matrix expansion output circuit are turned on, if no isolation circuit is set, due to electromagnetic interference, there will also be a voltage between 0 - 24V on the loads L 4 and L 3 , resulting in signal crosstalk between the rows and columns of the matrix expansion output circuit. Therefore, the parasitic loop generated by electromagnetic interference between the loads is cut off by the isolation unit, avoiding affecting the loads at the intersections of the corresponding rows and columns when the loads in different rows and columns of the circuit are turned on simultaneously, improving the reliability of input and output expansion, and ensuring that each output point can stably drive the load. In addition, the isolation unit can also play an isolation role between the load and the output point, and can be widely applied to various controllers, effectively simplifying the expansion method.

[0015] 2. In the extended output, a relay is used to control the on / off of the working circuit. With low impedance, it reduces the voltage loss and effectively improves the operating efficiency of the system.

[0016] 3. The present invention can reduce the error rate caused by the width of the input signal being less than the column scanning time and improve the signal capture success rate. At the same time, when the scanning interval is short and the load drive subroutine has not been executed yet, this method can increase the signal holding time and improve the program running stability. For a PLC controller, the input expansion is driven by a ladder diagram program. When the control accuracy requirement is high, the execution time of the load drive subroutine of the PLC controller is often longer than the matrix scanning time of the ladder diagram program. This leads to the situation that when the load drive subroutine has not been executed completely, the ladder diagram program has already been executed for the second time. At this time, the load drive subroutine will have an execution conflict, causing the load to malfunction. Therefore, a power-off delay time is set for each controller output terminal, so that after the controller output terminal of the first column of the matrix expansion output circuit, the controller output terminals of the remaining columns start to execute the scan after a certain period of time in sequence. During this period, all the controller output terminals are in a signal-free state to improve the execution efficiency of the load drive subroutine and avoid load malfunction.

[0017] 4. The method of the present invention improves the utilization efficiency of the input / output points of the controller, reduces the actual number of input / output points used by the controller, shrinks the volume of the control system, saves costs, and improves the running efficiency of the control program. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the circuit diagram of one input expansion method of the present invention;

[0019] Figure 2 It is the circuit diagram of another input expansion method of the present invention;

[0020] Figure 3 It is the circuit diagram of the output expansion of the present invention;

[0021] Figure 4 It is the ladder diagram program scan timing diagram of the present invention;

[0022] Figure 5 It is the structural schematic diagram of the multi-point unloader of the present invention;

[0023] Figure 6 It is the hardware connection diagram of the input / output expansion model of the multi-point unloader of the present invention;

[0024] In the figure, 1 - main body of the unloader; 2 - feed inlet; 3 - discharge outlet; 4 - drive motor; 5 - hopper; 6 - cylinder; 7 - conical nozzle; 8 - transmission chain; 9 - guide wheel; 10 - towing rope; 11 - slider; 12 - compression spring; 13 - discharge plate; 14 - driven wheel; 15 - stud;

[0025] 100, XYJ-KRDZK-32MT integrated control module; 200, 4×3 diode isolation module; 300, input sensing module; 400, relay module; 500, output load module; 600, 3×3 diode isolation module. Specific embodiments

[0026] The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but are not used to limit the protection scope of this application.

[0027] The present invention is a matrix expansion method (hereinafter referred to as the method) for realizing multi-point input and output of a controller, including input expansion and output expansion; assuming that the input end of the controller is X and the output end is Y, the input end X of the controller includes the input end X of the controller 0 ~X m and the output end Y of the controller includes the output end Y of the controller 0 ~Y n Then the size of the matrix expansion input circuit is m×n, that is, the number of input points that can be expanded by this matrix expansion input circuit is m×n, and both m and n are positive integers; assuming that the output ends of the controller for row expansion in the output expansion are Y 0 ~Y i and the output ends of the controller for column expansion are Y j ~Y n Then the size of the matrix expansion output circuit is i×(n - j), that is, the number of output points that can be expanded by this matrix expansion output circuit is i×(n - j), and i≠j; the intersection of the row and column of the matrix expansion input circuit represents the circuit output point, that is, O 0,0 ~O m,n represents the circuit output point;

[0028] When the pulse signals are connected to the controller input ends X 0 ~X m , the expansion method shown in Figure 1 is adopted. It is required that the signals between different rows and columns of the matrix expansion input circuit are mutually exclusive, that is, they are not simultaneously at a high level. The signal width of the controller input ends X 0 ~X m is greater than the time for the controller output ends Y 0 ~Y n to conduct in turn. Otherwise, the situation of losing the controller input signal may occur; the controller output ends Y 0 ~Y nWhen set to high level in turn, the input terminal X of the controller obtains n + 1 groups of input states in turn; for example, when the output terminal Y of the controller 0 is turned on, the output point O of the reading circuit 0,0 ~O m,0 is read, with the input terminal X of the controller 0 as the expansion point, then the external current flows out from the input terminal X of the controller 0 and passes through X 0 →Y 0 , then passes through the contact of the output terminal Y of the controller 0 and flows out from the common terminal COM of the output terminal Y of the controller 0 , and finally flows back to the COM terminal of the input terminal X of the controller 0 , thereby turning on the input terminal X of the controller 0 ;

[0029] When a pulse signal or a digital signal is connected to the input terminal X of the controller 0 ~X m , the expansion method shown in Figure 2 is adopted. There is no requirement for a strong logical relationship between signals. Diodes are added to the matrix expansion input circuit. A diode is connected between each input terminal of the controller and the corresponding circuit output point. Between the remaining adjacent circuit output points in each row of the matrix expansion input circuit except for the circuit output points connected to the input terminals of the controller, a diode is connected; if a digital signal is connected to the input terminal of the controller and the expansion method shown in Figure 1 is adopted, signal crosstalk between different columns will occur in the matrix expansion input circuit. For example, when a digital signal is connected to the input terminal X of the controller 0 , when the control program scans the output terminal Y of the controller 0 , the current flow direction is X 0 →Y 0 . At this time, if the output terminal Y of the controller 1 is scanned, it will cause the circuit output points O 0,0 and O 0,1 to output high level simultaneously, thus forming signal crosstalk. The diode can eliminate the signal crosstalk caused by the digital signal and maintain the stable operation of the circuit; the diode can be a rectifier diode or a Schottky diode; when the output terminal Y of the controller 0 is turned on, the output points O of the reading circuit ’ 0,0 ~O ’ m,0 are read, with the input terminal X of the controller 0 as the expansion point, then the external current flows out from the input terminal X of the controller 0 and passes through X 0 →D 1 →Y 0, and then through the output terminal Y of the controller 0 The contact flows out from the common terminal COM of the controller output terminal and finally flows back to the COM terminal of the controller input terminal, so that the controller input terminal X 0 is turned on; D 1 represents a diode located between the controller input terminal X 0 and the circuit output point O ’ 0,0 ;

[0030] Figure 3 is the circuit diagram for output expansion, and the output expansion incorporates circuit isolation technology; loads are provided between the respective controller output terminals of the rows and columns of the matrix expansion output circuit, and each load is respectively connected through an isolation unit and a controller output terminal located on the column of the matrix expansion output circuit and connected to the load; the isolation unit is a diode, the positive electrode of the diode is connected to the load, and the negative electrode is connected to the controller output terminal; for example, the controller output terminals for row-by-row expansion of the matrix expansion output circuit are Y 5 、Y 6 、Y 7 , and the controller output terminals for column-by-column expansion are Y 2 、Y 3 、Y 4 , then one end of the switch K 5 of the controller output terminal Y 1 is connected to the positive electrode of the diode D 1 through the load L 1 , the negative electrode of the diode D 1 is connected to one end of the switch K 2 of the controller output terminal Y 4 , one end of the switch K 5 of the controller output terminal Y 1 is connected to the positive electrode of the diode D 2 through the load L 2 , the negative electrode of the diode D 2 is connected to one end of the switch K 3 of the controller output terminal Y 5 , one end of the switch K 5 of the controller output terminal Y 1 is connected to the positive electrode of the diode D 3 through the load L 3 , the negative electrode of the diode D 3 is connected to one end of the switch K 4 of the controller output terminal Y 6 , the other end of the switch K 5 of the controller output terminal Y 1 is connected to a high level, and the switches K 4 ~K 6The other end is connected to a low level, and the connection method between the controller output terminals of the remaining rows and the controller output terminals of each column is the same; when the controller output terminal Y 2 is turned on with Y 5 , the external current flow direction is Y 5 →K 1 →L 1 →D 1 →K 4 →Y 2 . At this time, the load L 1 is in a high level state, and other loads are all in a low level state (voltage is 0V), so that the load L 1 works; the isolation circuit is to eliminate the signal crosstalk between different rows and different columns of the matrix expansion output circuit and ensure the stability of the controller output signal;

[0031] To make a certain load work, just control the switch of the controller output terminal corresponding to the row and column where the load is located in the matrix expansion output circuit to be turned on. When the switch of the controller output terminal corresponding to a certain row is turned on, the switches of the controller output terminals corresponding to each column may be turned on; or when only the switch of the controller output terminal of a certain column is turned on, the switches of the controller output terminals corresponding to each row may be turned on; randomly turn on the loads of any row and column of the matrix expansion output circuit, and no signal crosstalk will occur in the matrix expansion output circuit.

[0032] It is required that there is a voltage difference between the input terminal and the output terminal of the controller, that is, one end is a high level and the other end is a low level; the switches of each controller output terminal are all ordinary relays; if the controller is an STM32 microcontroller, it can define the pin as a pull-up mode or a pull-down mode. Assuming that pin 1 is defined as a pull-up mode (high level) and pin 2 is defined as a pull-down mode (low level), then pin 1 is equivalent to the controller input terminal X 0 , and pin 2 is equivalent to the controller output terminal Y 0 . In the input expansion, the external current flow direction is pin 1→D 1 →pin 2; for the output expansion, only need to pre-define any two pins of the STM32 microcontroller as floating input mode (the level is defined by an external signal), the row signal of the matrix expansion output circuit is connected to a low level, and the column signal is connected to a high level. The controller can also be other controllers such as a 51 single-chip microcomputer, and the matrix expansion method of input and output is the same.

[0033] When the controller is a PLC controller, the input expansion is controlled by a ladder diagram program. As Figure 4 shown, the ladder diagram program scans line by line. When scanning the controller output terminals Y 0 and Y 1 , that is, scanning the controller output terminals Y 0 and Y 1Set to high level in turn, the controller input terminal X 0 , X 1 Both are driven by external input signals, M 0 、M 1 They are the controller input terminals X 0 , X 1 The effective auxiliary bit of the drive signal; if the controller output terminal Y 0 At the end of the high level, the controller input terminal X 0 The driving signal is set to a high level, generating a high pulse to turn the auxiliary position M 0 The signal is set to a high level; in some working conditions, such as when the two switches are pressed at the same time, when the controller output terminal Y 0 At the end of the high level, the controller input terminal X 0 The driving signal disappears, and the controller output terminal Y 1 At high level, the controller input terminal X 1 The driving signal is set to a high level, generating a high pulse, which turns the auxiliary position M 1 The signal is set to high level, and the auxiliary position M 0 With M 1 There is a coexistence period, although the time is short, but this period cannot be ignored, it is easy to cause load malfunction; therefore, in order to eliminate the auxiliary position M 0 With M 1 During the coexistence period, a power-off delay time is set for the controller output. The power-off delay time means that after scanning the controller output of the first column of the matrix expansion output circuit, the controller outputs of the remaining columns are sequentially extended for a period of time before starting to scan. During this period of time, all controller outputs are in a no-signal state to overcome the defect of load malfunction caused by the execution time of the ladder diagram program of the PLC controller being greater than the scanning time; the power-off delay time is usually 20 to 30ms.

[0034] Example

[0035] This embodiment takes the PLC control system of a multi-point unloading machine as an example to illustrate the matrix expansion method for realizing multi-point input and output of the controller. Figure 6 As shown, it includes a discharger body 1, a feed port 2, a discharge port 3, a drive motor 4, a hopper 5, a cylinder 6, a conical guide nozzle 7, a transmission chain 8, a guide wheel 9, a traction rope 10, a slider 11, an extrusion spring 12, a discharge plate 13, a driven wheel 14 and a stud 15. The working principle is: the material enters the discharger from the feed port 2, the drive motor 4 drives the driven wheel 14 to work, and the material is lifted to the hopper 5. If the material is discharged at the hopper, the cylinder 6 at the hopper is controlled to work, and the hopper is opened for discharge.

[0036] In this embodiment, the matrix expansion method for multi-point input and output of the controller is applied to the working scenario of the five-point unloader. The XYJ-KRDZK-32MT integrated controller is used as the main control unit. The input points of the XYJ-KRDZK-32MT integrated controller are 16, and the output points are 16. For the working process of the five-point unloader, the signal characteristics of each control object are shown in the following table;

[0037] Table 1 Signal characteristics of each control object

[0038]

[0039] Compared with the process of the single-point unloader, the process of the five-point unloader has a process of switching between manual unloading and automatic unloading, and there is a situation where two bins unload at the same time. At this time, there are multiple high-level states of the signal of the obstruction rotary level gauge and the magnetic reed signal in the input signal at the same time, and there are multiple high-level states of multiple signals of the bin lights in the output signal at the same time. According to the control requirements, the controller of the five-point unloader requires a total of 23 input points and 13 output points. Therefore, the method of the present invention is used to expand the input points and output points of the XYJ-KRDZK-32MT integrated controller. In this embodiment, the input expansion of 3 output points and 4 input points is adopted, and a total of 12 input points are expanded. The output expansion of 3 output points and 3 output points is adopted, and a total of 9 output points are expanded;

[0040] The matrix input-output expansion system designed in this embodiment is as Figure 6 shown, including the XYJ-KRDZK-32MT integrated control module 100, the 4×3 diode isolation module 200, the input sensing module 300, the relay module 400, the output load module 500, and the 3×3 diode isolation module 600. The XYJ-KRDZK-32MT integrated control module 100 is a 32-channel controller with Mitsubishi FX2N as the control core, including 16 input units and 16 output units. Different from the traditional FX2N PLC, the XYJ-KRDZK-32MT integrated control module 100 can flexibly switch between the relay output mode and the transistor output mode. At the same time, the YJ-KRDZK-32MT integrated control module 100 is equipped with RS485, RS232, and CAN bus communication methods, and can perform data transmission with other control modules. Since the column scanning interval required for matrix expansion is short, the transistor output mode is adopted, which can achieve high-speed output and drive servo drivers, stepper motors, etc. The 4×3 diode isolation module 200 uses rectifier diodes or Schottky diodes. The isolation and filtering effect of Schottky diodes is better than that of rectifier diodes. Therefore, Schottky diodes are used in this embodiment. The negative poles of the Schottky diodes are connected to the input sensing module 300, and the positive poles of the Schottky diodes are connected to the input terminal X of the XYJ-KRDZK-32MT integrated control module 1005 、X 6 、X 7 and X 10 ; The 4×3 diode isolation module 200 is small in size and easy to install in the control cabinet; The input sensing module 300 is connected to the input components of the five-point unloading machine. To maximize the utilization rate of input and output points, the start button, stop button, bin 1-5 selection buttons, and 5 reed sensor signals are connected to the 4×3 diode isolation module 200. Among them, the start signal and stop signal are mutually exclusive signals, and different reed sensor signals may simultaneously be in the high-level state. At this time, the 4×3 diode isolation module 200 can eliminate the signal crosstalk between different sensor signals and improve the stability of the system; The relay module 400 uses an SJ1S-05B type mechanical relay, which has higher driving ability and service life. The contacts of the relay are connected to the load, and one end of the relay coil is connected to the output terminal Y 4 ~Y 7 、Y 10 and Y 11 of the XYJ-KRDZK-32MT integrated control module 100, where the relay coils on one side of the output terminals Y 4 ~Y 6 are connected to 24V, and the relay coils on one side of Y 7 、Y 10 、Y 11 are connected to 0V; Taking the conduction of the output terminals Y 4 and Y 7 as an example, the current direction is Y 4 → relay coil → relay contact → load → diode → relay contact → relay coil → Y 7 ; The output load module 500 is connected to the output load of the five-point unloading machine. To maximize the utilization rate of output points, the start lamp, stop lamp, and bin lamps 1-5 are connected to the 3×3 diode isolation module 600. Among them, the start lamp and stop lamp are mutually exclusive signals, and there are also cases where two of the bin lamps 1-5 are simultaneously in the high-level state. At this time, the 4×3 diode isolation module 200 can eliminate the signal crosstalk between different output points. At the same time, it can allow multiple signals to output high levels simultaneously, enabling the device to have a broader application scenario; The 3×3 diode isolation module 600 can select rectifier diodes or Schottky diodes, and the negative electrodes of the diodes are connected to the output terminals Y 7 、Y 10 、Y 11 , and the positive electrodes are connected to the load.

[0041] To make the extension method of the present invention have better popularization, Table 2 shows the matrix input-output extension methods of different controllers for the 1-13 point unloader. The selected controller models are XYJ-KRDZK-32MT (16 points input, 16 points output) and XYJ-KRDZK-56MT (32 points input, 24 points output).

[0042] Table 2 Input-output expansion of different controllers for different types of unloaders

[0043]

[0044]

[0045] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. However, the protection scope of the present invention cannot be limited thereby.

[0046] Matters not described in the present invention are applicable to the prior art.

Claims

1. A matrix expansion method for realizing multi-point input and output of a controller, including input expansion and output expansion; Characterized in that, Assume that the input end of the controller is X and the output end is Y. The input end X includes the input end X of the controller 0 ~X m , and the output end Y includes the output end Y of the controller 0 ~Y n , then the number of expanded input points is m×n; assume that the output end of the controller for row - by - row expansion in output expansion is Y 0 ~Y i , and the output end of the controller for column - by - column expansion is Y j ~Y n , then the number of expanded output points is i×(n - j), i≠j; m, n, i, and j are all positive integers; When the controller input terminals X 0 ~X m are connected to pulse signals or digital signals, diodes are added to the matrix expansion input circuit. A diode is connected between each controller input terminal and the circuit output point connected to this controller input terminal. Except for the circuit output points connected to the controller input terminals in each row of the matrix expansion input circuit, a diode is connected between the remaining adjacent circuit output points; each intersection of the rows and columns of the matrix expansion input circuit is a circuit output point; In output expansion, loads are provided between the output terminals of each controller for the rows and columns of the matrix expansion output circuit. Each load is respectively connected through an isolation unit and the output terminal of the controller located on the column of the matrix expansion output circuit to which the load is connected. The isolation unit is a diode, with the positive pole of the diode connected to the load and the negative pole connected to the controller output terminal. Assume that the output terminal of the controller for row expansion in the matrix expansion output circuit is Y 5 , and the output terminal of the controller for column expansion is Y 2 、Y 3 、Y 4 . Then, one end of the switch K 5 of the controller output terminal Y 1 is connected to the positive pole of the diode D 1 through the load L 1 . The negative pole of the diode D 1 is connected to one end of the switch K 2 of the controller output terminal Y 4 . One end of the switch K 5 of the controller output terminal Y 1 is connected to the positive pole of the diode D 2 through the load L 2 . The negative pole of the diode D 2 is connected to one end of the switch K 3 of the controller output terminal Y 5 . One end of the switch K 5 of the controller output terminal Y 1 is connected to the positive pole of the diode D 3 through the load L 3 . The negative pole of the diode D 3 is connected to one end of the switch K 4 of the controller output terminal Y 6 . The other end of the switch K 5 of the controller output terminal Y 1 is connected to a high level, and the other ends of the switches K 4 ~K 6 are connected to a low level. When the controller output terminals Y 2 and Y 5 are conducting, the external current flow direction is Y 5 →K 1 →L 1 →D 1 →K 4 →Y 2 . At this time, the load L 1 is in a high level state, and other loads are in a low level state, so that the load L 1 works.

2. The matrix expansion method for realizing multi-point input and output of a controller according to claim 1, Characterized in that, The switch K 1 , K 4 ~K 6 are all relays.

3. The matrix expansion method for realizing multi-point input and output of a controller according to claim 1, Characterized in that, The controller is a PLC controller, an STM32 microcontroller or a 51 single-chip microcomputer.

4. The matrix expansion method for realizing multi-point input and output of a controller according to claim 3, Characterized in that, When the controller is a PLC controller, the input expansion is controlled by a ladder diagram program, and a power-off delay time is set for the output end of the controller, that is, after scanning the output end of the controller in the first column of the matrix expansion output circuit, the output ends of the controller in the remaining columns are sequentially extended for a period of time before starting to execute the scan. During this period, all the output ends of the controller are in a signal-free state.

5. The matrix expansion method for realizing multi-point input and output of a controller according to claim 4, Characterized in that, The power-off delay time is 20 - 30 ms.

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