Voltage-controlled two-wire system 4-20mA constant current signal source based on TRIZ theory

Abstract

The invention provides a voltage-controlled two-wire system 4-20mA constant current signal source based on a TRIZ theory. The reference voltage is provided for the main control MCU unit and the PWM modulation module; the independent power supply supplies power to the input network to ensure the work of a control loop device; setting parameters of the PWM modulation module are adjusted by an encoder, the master control MCU receives the setting parameters and outputs modulation pulses to the PWM modulation module in combination with feedback signal giving, and the other path of data signals are transmitted to the display unit to display related data; the impedance conversion isolates the constant current reference and the network input part in the circuit; the constant current reference is transmitted to the main control MCU unit through the PWM module, so that the control of constant current driving and amplification is realized; anti-reverse connection and filtering protection constant-current driving amplification and front-end circuit burnout are realized; the output terminal provides precise constant current source signals to the outside and converts voltage into constant current power supply. Through giving of a voltage control signal, temperature control compensation of a chip and constant current reference feedback, the output terminal outputs a two-wire system constant current source with constant current precision within 0.02%.

Description

Technical Field

[0001] The invention relates to an industrial 4-20mA signal sensor constant current signal source in the field of ships, in particular to a voltage-controlled two-wire 4-20mA constant current signal source based on TRIZ theory. Background Art

[0002] During the shipbuilding process, 4~20mA sensors for various current controls such as temperature, pressure, flow, etc. need to be debugged and tested after installation, and the parameters need to be verified point by point within the full range to ensure that the equipment can collect stable, high-precision 4~20mA accurate data when working, avoiding the need to adjust the sensor again due to insufficient equipment accuracy, which will cause secondary construction.

[0003] However, the inventors of this application found that the above technology has at least the following technical problems in the process of implementing the technical solution of the invention in the embodiment of this application: The sensor body cannot simulate each working condition point and cannot adjust the working status of each point. According to survey statistics, the equipment with an accuracy deviation of 4~20mA constant current signal source within the range of ±0.02% is small, large in size, expensive, and not suitable for large-scale procurement.

[0004] In view of the above problems and current situation, a constant current signal source device with small size, low price, stable adjustment of output current parameters and high precision is invented, which is more conducive to the use of ship construction tests. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a voltage-controlled two-wire 4~20mA constant current signal source based on TRIZ theory to solve the problems of accuracy of test data and ensuring the consistency of parameter setting and output. The constant current signal source adopts a two-wire output port, adjusts the input network voltage change rate through an encoder, and realizes the control of the output network constant current through a setting network conversion, thereby achieving the purpose of stable regulation and solving the technical problem of the accuracy of the constant current signal source test data.

[0006] The solution adopted by the present invention to solve the technical problem is: Based on TRIZ theory, the voltage-controlled two-wire 4~20mA constant current signal source includes reference voltage, PWM modulation module, impedance conversion, constant current reference, constant current drive and amplification, reverse connection protection and filtering, output terminal, independent power supply, main control MCU unit, encoder input, display unit and constant current power supply conversion; The reference voltage provides reference voltage for the main control MCU unit and PWM modulation module; the independent power supply provides power for the input network to ensure the normal operation of the control loop components; the PWM modulation module is adjusted by the encoder input setting parameters, the main control MCU unit receives the setting parameters and combines the feedback signal to give the output modulation pulse to the PWM modulation module, and another data signal is transmitted to the display unit to display the relevant data; the impedance transformation isolates the constant current reference and the network input part in the circuit; the constant current reference is transmitted to the main control MCU unit through the PWM modulation module to realize the control of constant current drive and amplification; anti-reverse connection and filtering effectively protect the constant current drive amplification and the front-end circuit from burning; the output terminal provides a precise constant current source signal to the outside, and at the same time converts the voltage into a constant current power supply conversion power supply. Among them, the independent power supply adopts an independent control network.

[0007] In order to further solve the technical problem to be solved by the present invention, the present invention provides a method for applying a voltage-controlled two-wire 4-20mA constant current signal source based on TRIZ theory. Based on TRIZ theory, a segmentation method, feedback, and combination trinity method are adopted to reduce the mutual interference of loop noise and interference sources by segmenting the input and output power supplies; a constant current reference feedback network is added to ensure the consistency of a given input and constant current drive amplification, and a combination method is adopted to merge the constant current reference and the proportional amplification current network to further improve the stability and sensitivity of the control signal output; the method comprises the following steps: First, turn on the independent power supply to power the main control MCU unit and the reference voltage in the input network; Secondly, the encoder input adjustment setting parameters and feedback voltage control parameters are collected by the main control MCU unit at the same time; Secondly, the main control MCU unit outputs the modulated pulse to the PWM modulation module, and drives the display unit to display the current data and the given data at the same time. The PWM modulation module realizes constant voltage isolation from the constant current reference through impedance transformation, and the constant current drive and amplification uses the constant current reference as a reference source to further amplify the driving current; Secondly, the constant current power supply conversion provides 10~24V voltage from the output terminal to ensure the normal power supply of impedance edge and constant current drive amplifier. The introduction of anti-reverse connection and filtering prevents external wiring misoperation and noise disturbance; Finally, the output terminal outputs a two-wire constant current source with a controllable constant current accuracy within 0.02%.

[0008] Positive effect: due to the given voltage control signal, temperature control compensation of the chip and constant current reference feedback, the output terminal outputs a two-wire constant current source with a constant current accuracy within 0.02%. Since the device is small in size, easy to carry, and low in cost, it plays a key role in the utilization and transformation of the results.

[0009] The power supply of the present invention adopts a network-independent design concept, and the encoder pulse adjustment method can adjust the reference voltage to a resolution of one sixty thousandth, and the actual output accuracy is controlled within 0.02%. At the same time, the dynamic data can be updated in real time through the OLED screen, which is more intuitive and realistic. The signal source device port is easy to connect, has an anti-reverse connection design, and does not cause the risk of electric shock to the human body. It can replace the conventional constant current signal generator on the market, is fully suitable for the calibration of ship-type 4~20mA signal sensors, and can also be used as a signal detection device for related high-precision electronic products.

[0010] It is suitable for application as a voltage-controlled two-wire 4~20mA constant current signal source based on TRIZ theory. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The description of the present invention is given for the purpose of example and description, and is not exhaustive or limits the present invention to the disclosed form. Many modifications and changes are obvious to ordinary technicians in this field. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and enable ordinary technicians in this field to understand the present invention and design various embodiments with various modifications suitable for specific purposes.

[0012] Figure 1 This is a schematic diagram of the structure of this embodiment.

[0013] In the figure, 1. reference voltage, 2. PWM modulation module, 3. impedance conversion, 4. constant current reference, 5. constant current drive and amplification, 6. anti-reverse connection and filtering, 7. output terminal, 8. independent power supply, 9. main control MCU unit, 10. encoder input, 11. display unit, 12. constant current power supply conversion. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Although the embodiments of the present invention have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the attached claims and their equivalents. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0015] As shown in the figure, the voltage-controlled two-wire 4~20mA constant current signal source based on TRIZ theory includes a reference voltage 1, a PWM modulation module 2, an impedance conversion 3, a constant current reference 4, a constant current drive and amplification 5, anti-reverse connection and filtering 6, an output terminal 7, an independent power supply 8, a main control MCU unit 9, an encoder input 10, a display unit 11 and a constant current power supply conversion 12; Reference voltage 1, providing reference voltage for main control MCU unit 9 and PWM modulation module 2; The independent power supply 8 provides power to the input network to ensure the normal operation of the control loop components; The PWM modulation module 2 adjusts the setting parameters by the encoder input 10, the main control MCU unit 9 receives the setting parameters and combines the feedback signal to give the output modulation pulse to the PWM modulation module 2, and another data signal is transmitted to the display unit 11 to display the relevant data; The impedance transformation 3 isolates the constant current reference 4 and the network input part in the circuit; the constant current reference 4 is connected to the main control MCU unit 9 through the PWM modulation module 2 to realize the control of the constant current drive and amplification 5; Anti-reverse connection and filtering 6 effectively prevent constant current drive and amplifier 5 and front-end circuit from burning; The output terminal 7 provides a precise constant current source signal to the outside, and at the same time converts the voltage into a constant current power supply converter 12 power supply.

[0016] The independent power source 8 is powered by an independent control network.

[0017] The working process of this embodiment: Based on TRIZ theory, the method of segmentation, feedback and combination is adopted to reduce the mutual interference of loop noise and interference sources by segmenting the input and output power supply; a constant current reference feedback network is added to ensure the consistency of given input and constant current drive amplification, and the constant current reference and proportional amplification current network are combined by a combination method to further improve the stability and sensitivity of the control signal output; the following steps are included: First, the independent power supply 8 is turned on to supply power to the main control MCU unit 9 and the reference voltage 1 in the input network; Secondly, the encoder input 10 adjusts the setting parameters and the feedback voltage control parameters are collected by the main control MCU unit 9 at the same time; Secondly, the main control MCU unit 9 outputs the modulation pulse to the PWM modulation module 2, and drives the display unit 11 to display the current data and the given data, and the PWM modulation module 2 realizes constant voltage isolation with the constant current reference 4 through impedance transformation 3, and the constant current driving and amplification 5 uses the constant current reference 4 as a reference source to further amplify the driving current; Secondly, the constant current power supply conversion 12 provides a 10~24V voltage from the output terminal 7 to ensure the normal power supply of the impedance edge and the constant current drive amplifier 5, and the introduction of anti-reverse connection and filtering 6 prevents external wiring misoperation and noise disturbance; Finally, the output terminal 7 outputs a two-wire constant current source with a controllable constant current accuracy within 0.02%.

[0018] The features of this embodiment are as follows: Since the device adopts encoder control, the adjustment parameters are easy to operate, and the voltage is adjusted by frequency division through 16-bit binary code. The voltage control precision resolution achieves one sixty thousandth of the regulated voltage, solving the problem of low adjustment precision of conventional potentiometers.

[0019] Since the PWM modulation module of the device adopts a constant current feedback network and a chip temperature compensation correction scheme, the temperature drift and low precision problems caused by the constant current reference and chip temperature changes are solved.

[0020] Since the device adopts a two-wire port and anti-reverse connection, the number of ports and the safety problem of wiring short circuit are simplified.

[0021] Since the display unit of the device adopts an OLED screen, the real-time current, voltage, compensation temperature and other contents can be displayed intuitively.

[0022] Since the device is small in size, easy to carry and low in cost, it plays a key role in the utilization and transformation of the results.

[0023] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Based on TRIZ theory, the voltage-controlled two-wire 4-20mA constant current signal source is characterized by: It includes a reference voltage (1), a PWM modulation module (2), an impedance conversion (3), a constant current reference (4), a constant current drive and amplification (5), anti-reverse connection and filtering (6), an output terminal (7), an independent power supply (8), a main control MCU unit (9), an encoder input (10), a display unit (11) and a constant current power supply conversion (12); A reference voltage (1) is used to provide a reference voltage for the main control MCU unit (9) and the PWM modulation module (2); The independent power supply (8) provides power to the input network to ensure the normal operation of the control circuit components; The PWM modulation module (2) adjusts the set parameters through the encoder input (10), the main control MCU unit (9) receives the set parameters and combines the feedback signal to give an output modulation pulse to the PWM modulation module (2), and another data signal is transmitted to the display unit (11) to display relevant data; The impedance transformation (3) isolates the constant current reference (4) and the network input part in the circuit; the constant current reference (4) is transmitted to the main control MCU unit (9) through the PWM modulation module (2) to realize the control of the constant current drive and amplification (5); Anti-reverse connection and filtering (6) effectively protect constant current drive and amplifier (5) and front-end circuits from burning out; The output terminal (7) provides a precise constant current source signal to the outside, and at the same time converts the voltage into a constant current power supply converter (12); The independent power source (8) is powered by an independent control network.

2. The method of applying the TRIZ theory-based voltage-controlled two-wire 4-20mA constant current signal source according to claim 1 is characterized in that: Based on TRIZ theory, the trinity of segmentation, feedback and combination is adopted to reduce the mutual interference of loop noise and interference sources by segmenting the input and output power supplies; a constant current reference feedback network is added to ensure the consistency of given input and constant current drive amplification, and a combination method is used to merge the constant current reference with the proportional amplification current network to further improve the stability and sensitivity of the control signal output; The following steps are involved: First, an independent power supply (8) is turned on to supply power to the main control MCU unit (9) and the reference voltage (1) in the input network; Secondly, the encoder input (10) adjusts the setting parameters and the feedback voltage control parameters are simultaneously collected by the main control MCU unit (9); Secondly, the main control MCU unit (9) outputs the modulation pulse to the PWM modulation module (2), and drives the display unit (11) to display the current data and the given data, while the PWM modulation module (2) realizes constant voltage isolation with the constant current reference (4) through impedance transformation (3), and the constant current driving and amplification (5) uses the constant current reference (4) as a reference source to further amplify the driving current; Secondly, the constant current power supply conversion (12) provides a 10-24V voltage from the output terminal (7) to ensure the normal power supply of the impedance edge and the constant current drive amplifier 5, and the introduction of anti-reverse connection and filtering (6) prevents external wiring misoperation and noise disturbance; Finally, the output terminal (7) outputs a two-wire constant current source with a controllable constant current accuracy within 0.02%.

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