CN103984279B - Mixed signal experiment module based on PLC - Google Patents

Abstract

The invention discloses a mixed-signal experiment module based on a PLC controller, which includes a PCB board, a PLC controller and a PLC analog expansion module; the PCB board includes a DC-DC circuit, a signal setting and a controlled object circuit, and a digital signal input Output circuit, decoding latch and digital display circuit, PCB board input and output interface, first terminal block and second terminal block; PLC controller includes power supply circuit, PLC controller input and output interface and central processing unit; PLC analog expansion The module includes PLC analog expansion module input and output interface; digital signal input and output circuit, decoding latch and digital display circuit and PCB board input and output interface are all connected to the input and output interface of PLC controller through the first terminal block, and the signal is given and the controlled object circuit are connected to the input and output interfaces of the PLC analog expansion module through the second terminal block. The invention has the characteristics of low cost, common input and output interfaces, flexible and convenient use, less PLC resource occupation, convenient teaching and good application prospect.

Description

based on PLC Mixed Signal Experiment Module for Controllers

technical field

The invention relates to a mixed signal experiment module based on a PLC controller, belonging to the technical field of programmable controller teaching.

Background technique

In college teaching, PLC application technology is a technical professional course with strong practicality, and it is urgent to combine theory and practice. Therefore, PLC experiment is an important part of PLC teaching. At present, the PLC experiment module is usually a single-function experiment module, such as temperature measurement and control, switch value control and some other process analog control experiment modules. Every time an experiment is done, an experiment module needs to be replaced, which is costly and inconvenient to use. , when it is necessary to conduct experiments on analog and digital signals simultaneously, in the prior art, separate experimental modules for digital and analog signals are required to be combined, and the design is complex and expensive.

Furthermore, in the prior art, with the remodeling and upgrading of the PLC controller, the original experimental device is also scrapped, resulting in unnecessary waste.

Therefore, on the one hand, with the continuous development of PLC and application technology, the problems existing in the existing PLC experimental equipment are becoming more and more prominent; on the other hand, it is impossible for schools to update the experimental equipment frequently. The role of the PLC experimental device, the development of a general-purpose mixed-signal experimental module based on the PLC controller is an urgent problem to be solved at present.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art. The mixed signal experiment module based on PLC controller of the present invention can realize the closed-loop control of digital PID based on PLC, multi-channel signal measurement and control, display and alarm, traffic with countdown Experiments such as signal light control have powerful functions, low cost, universal input and output interfaces, flexible and convenient use, less PLC controller resource occupation, convenient teaching, and good application prospects.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A mixed signal experiment module based on PLC controller, including PCB board, PLC controller and PLC analog expansion module.

PCB board includes DC-DC circuit, signal setting and controlled object circuit, digital signal input and output circuit, decoding latch and digital display circuit, PCB board input and output interface, first terminal block and second terminal block; DC- The DC circuit is connected with the signal setting and the controlled object circuit, the digital signal input and output circuit, the decoding latch and the digital display circuit, and the input and output interface of the PCB board, and the signal setting and the controlled object circuit are connected with the second terminal block .

Described PLC controller comprises power supply circuit, PLC controller input and output interface, central processing unit, and power supply circuit is connected with PLC controller input and output interface, central processing unit, and described central processing unit is connected with PLC controller input and output interface connect.

The PLC analog expansion module includes the input and output interfaces of the PLC analog expansion module.

The digital signal input and output circuit, decoding latch and digital display circuit and PCB board input and output interfaces are all connected to the input and output interfaces of the PLC controller through the first terminal block, and the DC-DC circuit is connected to the power supply circuit on the PLC controller , the DC-DC circuit converts the voltage to supply power to all components on the PCB, the signal given and the controlled object circuit are connected to the input and output interfaces of the PLC analog expansion module through the second terminal block, and the PLC analog expansion module input The output interface is connected with the central processing unit through the expansion bus. Realize the signal transmission and control of the PLC controller, PCB board and PLC analog expansion module, and provide equipment for mixed experiments based on the PLC controller. The input and output of the PLC controller are expanded through the first terminal block, which can provide a variety of experiments project. The PCB board and the components of the PLC analog expansion module and the connection relationship between the components of this patent can adapt to various PLC controllers, the modification and upgrade of the PLC controller, and the PCB board and the PLC analog expansion module can continue to be used.

Signal given and controlled object circuit includes signal given module, analog second-order controlled object module, signal given module, simulated second-order controlled object module is connected with the input and output interface of PLC analog expansion module through the second terminal block .

The signal setting and controlled object circuit also includes an analog PI adjustment module, which is connected to the analog second-order controlled object module through a debugging switch, and the analog PI adjustment module is used for comparison with the results of the digital PID adjustment control of the PLC . The analog second-order controlled object module includes a first operational amplifier module, and the analog PI adjustment module includes a second operational amplifier module and peripheral components.

The decoding latch and digital display circuit includes several latch decoding drive modules and several digital tubes, each latch decoding drive module is respectively connected to a corresponding digital tube, and the latch decoding drive modules are connected through the first terminal The row is connected to the input and output interfaces of the PLC controller.

Preferably, there are four latch decoding drive modules and digital tubes.

The digital signal input and output circuit includes a button switch module and a light-emitting diode. The button switch module includes a switch without self-locking and a switch with self-locking. Both the button switch module and the light-emitting diode are connected to the input and output interfaces of the PLC controller through the first terminal block. The button switch module is used to simulate different signal requirements. When simulating short signals, use switches without self-locking for simulating short signals, and switches with self-locking for simulating long signals.

Preferably, the power supply circuit outputs 24V direct current, and the DC-DC circuit converts the 24V voltage into 12V voltage, and the DC-DC circuit is a DC-DC conversion circuit with isolation to reduce the signal interference of external signals to the test device.

The beneficial effects of the present invention are: the mixed-signal experiment module based on the PLC controller provided by the present invention utilizes the controlled object composed of the operational amplifier module to realize the digital PID closed-loop control based on the PLC, and at the same time, receives the signal from the PLC analog expansion module Analog signal, or use the switch input and output of the mixed signal test module, can realize the detection and control of switch signal and the detection and control of physical quantity in the simulation process, the connection between the components and components of the PCB board and PLC analog expansion module of this patent relationship, can adapt to a variety of PLC controllers, after the modification and upgrade of the PLC controller, the PCB board and the PLC analog expansion module can continue to be used, and various PLC control experiments can be carried out, low cost, universal input and output interfaces, flexible and convenient to use , Occupying less PLC resources, convenient for teaching, and has a good application prospect.

Furthermore, the PLC control of this patent can be compared with the results of analog control, and the parameter control settings are flexible. It can also complete experiments such as multi-channel signal measurement, control and display, and traffic signal control with countdown. It can also be used as a detection unit for complex control systems. And display unit, to meet the diverse teaching of PLC control.

Further, the PCB board of the present application is connected to the PLC controller and the PLC analog expansion module respectively through the first terminal block and the second terminal block, so that the experimental wiring is convenient and clear, and the experimental operation is convenient.

Description of drawings

Fig. 1 is the structural representation of the mixed signal experiment module based on PLC controller of the present invention;

Fig. 2 is the structure schematic diagram of the present invention including the components in the signal given and controlled object circuit;

Fig. 3 is a schematic circuit diagram of the decoding latch and digital display circuit of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the mixed signal experiment module based on PLC controller includes PCB board 1, PLC controller 2 and PLC analog expansion module 3.

PCB board 1 includes DC-DC circuit 101, signal setting and controlled object circuit 102, digital signal input and output circuit 103, decoding latch and digital display circuit 104, PCB board input and output interface 105, first terminal row 106 and The second terminal block 107; the DC-DC circuit 101 is connected with the signal setting and the controlled object circuit 102, the digital signal input and output circuit 103, the decoding latch and the digital display circuit 104, and the PCB board input and output interface 105, The signal setting and controlled object circuit 102 is connected to the second terminal block 107 .

PLC controller 2 comprises power supply circuit 201 and PLC controller input and output interface 202, central processing unit 203, and power supply circuit 201 is connected with PLC controller input and output interface 202, central processing unit 203, and central processing unit 203 is connected with PLC controller The input and output interfaces 202 are connected. The PLC analog expansion module 3 includes a PLC analog expansion module input and output interface 301 .

Digital signal input and output circuit 103, decoding latch and digital display circuit 104 and PCB board input and output interface 105 are all connected to PLC controller input and output interface 202 through first terminal block 106, DC-DC circuit 101 and PLC controller The power supply circuit 201 on the 2 is connected, and the DC-DC circuit converts the voltage to supply power to all components on the PCB board. The signal is given and the controlled object circuit 102 is connected to the input and output interface 301 of the PLC analog expansion module through the second terminal block 107 The input and output interface 301 of the PLC analog expansion module is connected with the central processing unit 203 through the expansion bus.

As shown in Figure 2, the signal given and controlled object circuit 102 includes a signal given module 102a, a simulated second-order controlled object module 102b and an simulated PI adjustment module 102c, the signal given module 102a, the simulated second-order controlled object module 102b is connected to the input and output interface 301 of the PLC analog expansion module through the second terminal block 107 . The analog PI adjustment module 102c is connected to the analog second-order controlled object module 102b through a debugging switch, and the analog PI adjustment module 102c is used for comparison with the result of the digital PID adjustment control of the PLC.

The decoding latch and digital display circuit 104 includes four latch decoding drive modules and four digital tubes, the four latch decoding drive modules are respectively connected to a corresponding digital tube, and the four latch decoding drive modules are all connected through The first terminal block 106 is connected to the input and output interface 202 of the PLC controller.

The digital signal input and output circuit 103 includes four button switch modules and 16 light-emitting diodes, the four button switch modules include two switches without self-locking and two switches with self-locking, four button switch modules and 16 light-emitting diodes The diodes are all connected to the input and output interface 202 of the PLC controller through the first terminal block 106 .

The power supply circuit 201 outputs 24V direct current, and the DC-DC circuit 101 includes the LM2596-12 chip and peripheral components. The DC-DC circuit 101 converts the 24V voltage into a 12V voltage. The DC-DC circuit 101 is a DC-DC conversion circuit with isolation. The 24V DC of the PLC controller is converted into 12V DC, and then output through the isolated DC-DC module to provide power for each circuit on the PCB.

The signal given module 102a simulates a 0-5V given signal from a 12V power supply through a potentiometer, connects to the 1-way input terminal of the input-output interface 301 of the PLC analog quantity expansion module, and connects to 4-way digital quantities on the PLC controller through four key switches At the input end, the simulated second-order controlled object module 102b includes a first operational amplifier module (the model is LM358), the simulated second-order controlled object module 102b can be connected with the simulated PI adjustment module 102c to verify the control effect, and the simulated PI adjustment module 102c Including the second operational amplifier module (model is LM358), to realize the difference between digital control and analog control.

As shown in Figure 3, described decoding latch and digital display circuit comprise four latch decoding driving modules U5, U6, U7, U8 (the model is CD4511) and four nixie tubes DS1, DS2, DS3, DS4 ( Common cathode digital tubes can be used), and the four latch decoding drive modules are respectively externally connected to the PLC controller input and output interface 202, and are respectively connected to a corresponding digital tube. The specific connection is as follows, the 8-way digital quantity of the PLC controller 2 The output signal is divided by resistors, among which 4 channels of decoding signals are connected to the input terminals of the latch decoding drive modules U5, U6, U7, and U8, and the other 4 channels are respectively connected to the input terminals of the latch decoding drive modules U5, U6, U7, and U8. Latch enable terminal, the 7-segment outputs (a, b, c, d, e, f, g) of the latch decoding drive modules U5, U6, U7, U8 are respectively connected to the digital tubes DS1, DS2, DS3, DS4 the corresponding end. The digital signal input and output circuit 103 includes sixteen LED indicator lights, of which 6 groups (12) of indicator lights are respectively connected to the other 6 digital output ports of the PLC, and 2 groups (4) of the indicator lights are respectively connected to the rest of the PLC. The 2-way digital output port, that is, 2 groups (4) indicator lights CAR-N and S_CAR, CAR-E and W_CAR are respectively connected to the remaining 2-way digital output ports of the PLC.

The working process of the mixed-signal experiment module based on the PLC controller of the present invention is as follows: PLC controller takes the PLC of Siemens S7-200 as an example, and this experiment module can be used as the platform of three typical experiments: based on the measurement and control system based on PLC, based on PLC PID closed-loop control system, PLC-based traffic signal light control system.

1. PLC-based multi-channel measurement and control system: The signal given module 102a on the PCB provides two channels of simulated measured physical quantities, which are input through the PLC analog quantity expansion module 3 (model EM235), compared with the internal given value, and output control Signal, and the upper and lower limits of the physical quantity can be set to alarm when the limit is exceeded, and the display of the measured physical quantity can be realized at the same time.

2. PLC-based PID closed-loop control system: the analog PI adjustment module 102c and the analog second-order controlled object module 102b can be connected through the debugging switch on the PCB board, and the output of the simulated second-order controlled object module 102b is expanded through the PLC analog quantity Module 3 (model EM235) inputs, changes the given value through the signal given module 102a, and observes the process and effect of PID closed-loop adjustment through the display of the output of the analog object.

3. PLC-based traffic signal light control system: 16 LED indicators on the PCB board respectively simulate 12 red, yellow and green indicator lights at intersections and the state of 4 cars at 4 intersections, controlled by PLC The digital output port is used for control, and the traffic control time of east-west and north-south directions can be counted down and displayed by digital tubes.

The mixed-signal experiment module based on the PLC controller provided by the present invention uses the controlled object composed of operational amplifiers to realize the digital PID closed-loop control based on the PLC, and can compare with the results of the analog control. The parameter setting is flexible, and multiple It can also be used as a detection unit and display unit for complex control systems, such as channel signal measurement, control and display, traffic signal control with countdown, etc. It has the characteristics of low cost, universal input and output interfaces, flexible and convenient use, and less PLC resource occupation, which is convenient for teaching , has a good application prospect.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. A mixed-signal experiment module based on a PLC controller, including a PLC controller (2), characterized in that it also includes a PCB board (1) and a PLC analog expansion module (3); The PCB board (1) includes DC-DC circuit (101), signal setting and controlled object circuit (102), digital signal input and output circuit (103), decoding latch and digital display circuit (104), PCB Board input and output interface (105), first terminal block (106) and second terminal block (107); said DC-DC circuit (101) and signal setting and controlled object circuit (102), digital signal input and output circuit (103), decoding latch and digital display circuit (104), PCB board input and output interface (105) are connected; The PLC controller (2) includes a power supply circuit (201), a PLC controller input and output interface (202) and a central processing unit (203); the power supply circuit (201) is connected to the PLC controller input and output interface (202), the central The processing unit (203) is connected, and the central processing unit (203) is connected to the PLC controller input and output interface (202); The PLC analog expansion module (3) includes a PLC analog expansion module input and output interface (301); The digital signal input and output circuit (103), the decoding latch and digital display circuit (104) and the PCB board input and output interface (105) are all connected to the PLC controller input and output interface (202) through the first terminal row (106) The DC-DC circuit (101) is connected to the power supply circuit (201) on the PLC controller (2), and the DC-DC circuit (101) converts the voltage to supply power to all components on the PCB, and the The signal setting and the controlled object circuit (102) are connected to the input and output interface (301) of the PLC analog expansion module through the second terminal block (107), and the input and output interface (301) of the PLC analog expansion module is connected to the central processing Unit (203) is connected. 2. The mixed signal experiment module based on PLC controller according to claim 1, characterized in that: the signal given and controlled object circuit (102) includes a signal given module (102a), an analog second-order controlled object The object module (102b), the signal given module (102a), and the analog second-order controlled object module (102b) are connected to the input and output interface (301) of the PLC analog expansion module through the second terminal block (107). 3. The mixed signal experiment module based on PLC controller according to claim 2, characterized in that: the signal given and controlled object circuit (102) also includes an analog PI adjustment module (102c), and the analog PI adjustment module (102c) is connected to the analog second-order controlled object module (102b) through a debugging switch, and the analog PI adjustment module (102c) is used for comparison with the result of the digital PID adjustment control of the PLC. 4. The mixed-signal experiment module based on PLC controller according to claim 1, characterized in that: the decoding latch and digital display circuit (104) includes several latch decoding drive modules and several digital tubes, so The latch decoding drive modules are all connected to a corresponding digital tube, and the latch decoding drive modules are connected to the PLC controller input and output interface (202) through the first terminal block (106). 5. The mixed-signal experiment module based on PLC controller according to claim 4, characterized in that: the number of the latch decoding drive module and the number of digital tubes are four. 6. The mixed signal experiment module based on PLC controller according to claim 1, characterized in that: the digital signal input and output circuit (103) includes a button switch module and a light emitting diode, and the button switch module includes a For a lock switch and a switch with self-lock, the push button switch module and the light emitting diode are connected to the input and output interface (202) of the PLC controller through the first terminal block (106). 7. The mixed signal experiment module based on PLC controller according to claim 1, characterized in that: the power supply circuit (201) outputs 24V direct current, and the DC-DC circuit (101) converts 24V voltage into 12V voltage . 8. The mixed-signal experiment module based on PLC controller according to claim 1, characterized in that: the DC-DC circuit (101) is a DC-DC conversion circuit with isolation. 9. The mixed-signal experiment module based on PLC controller according to claim 3, characterized in that: the simulated second-order controlled object module (102b) includes a first operational amplifier module, and the simulated PI adjustment module (102c ) including the second op amp module. 10. The mixed signal experiment module based on PLC controller according to claim 1, characterized in that: the input and output interface (301) of the PLC analog expansion module is connected to the central processing unit (203) through an expansion bus.