A composite multifunctional signal generating device

Abstract

The present invention discloses a composite multifunctional signal generating device, including a main control module, a power supply module, a current signal generator module and a human-computer interaction module; wherein the main control module is used to control the output of the power supply module and the current signal generator, and display the parameters in real time on the human-computer interaction module; the current generator is used to output a current constant current signal of a set range value; the power supply module is responsible for power input, including a USB auxiliary power supply, and its interior is mainly composed of an AC-DC power supply unit and N DC-DC power supply units; the AC-DC power supply unit is responsible for converting alternating current into direct current voltage, which is used as a common input of N DC-DC power supply units, generates different direct current voltages by stepping up or down, and finally switches gears through an N-choose-one switch. After the present invention adopts multiple power supplies and signal outputs, the work efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and in particular to a composite multifunctional signal generating device. Background Art

[0002] In the process of power production, various instruments are often used, and the use of instruments and even individual equipment requires external power supply to be used normally. At present, for equipment powered by AC voltage, the most commonly used on-site is a plug-in cable tray, and for some precision instruments powered by DC voltage, a specific DC regulated power supply is required. In actual on-site applications, multiple power supplies are often used at the same time, which will lead to many disadvantages and cannot reliably guarantee the continuous and stable operation of the equipment.

[0003] At present, the power supply of equipment and instruments has the following obvious disadvantages:

[0004] 1) The existing DC stable power supply still needs to be powered by an external AC voltage to be used normally, and the AC socket is often far away from the work site, requiring the use of an additional jack cable tray for intermediate connection. The multiple power supply structure brings about the clutter of work objects on site and lower power supply stability.

[0005] 2) The existing jack-type cable reel has no voltage display function, and the voltage can only be manually detected to see if it is sufficient, which is not conducive to safe use on site.

[0006] 3) The existing jack-type cable reel does not have the DC voltage output and current signal output functions, and requires the additional use of a current signal generator and a DC regulated power supply. Simple measurement work consumes a lot of manpower and material resources for preliminary preparation, resulting in high labor costs.

[0007] 4) Multiple power supply modes require the purchase of numerous power supply equipment. Some complete sets of products are imported foreign brands, which are expensive and difficult to purchase, increasing the production costs of the enterprise. Summary of the invention

[0008] In order to solve at least one technical problem existing in the above-mentioned background technology, the present invention provides a composite multifunctional signal generating device.

[0009] To achieve the above object, the technical solution of the present invention is:

[0010] A composite multifunctional signal generating device includes a main control module, a power supply module, a current signal generator module and a human-computer interaction module; wherein:

[0011] The main control module is used to control the output of the power supply module and the current signal generator, and display the parameters in real time on the human-computer interaction module;

[0012] The current generator is used to output a current constant current signal with a set range value;

[0013] The power supply module is responsible for power input, including the USB auxiliary power supply, and is mainly composed of an AC-DC power supply unit and N DC-DC power supply units; the AC-DC power supply unit is responsible for converting alternating current into direct current voltage, and the direct current voltage is used as the common input of the N DC-DC power supply units to generate different direct current voltages by stepping up or down, and finally switching the gears through the N-to-one switch; wherein a certain direct current voltage generated is output as the USB auxiliary power supply, and no switching is required, and N is a positive integer;

[0014] The AC-DC power supply unit is also used to directly output an alternating current voltage.

[0015] Furthermore, the current signal generator is a 4-20mA signal generator that outputs a 4-20mA constant current signal, and includes a 24V boost unit, a digital-to-analog converter DAC, and a constant current source generator; the 24V boost unit is responsible for powering the constant current source generator, the digital-to-analog converter DAC realizes programmable voltage output, and the constant current source generator linearly converts the voltage output by the DAC into a constant current output.

[0016] Furthermore, a solid-state relay is provided at the output end of the AC-DC power supply unit as a main switch. When the N-to-one switch switches gears, the main control module turns off the AC-DC power supply unit in advance. After the N-to-one switch gears are switched, the main control module turns on the AC-DC power supply unit again to supply power.

[0017] Furthermore, during the voltage switching process, the N-to-one switch is not powered.

[0018] Furthermore, the AC-DC power supply unit converts the AC power into a DC 48V voltage, which is used as the common input of the four DC-DC power supply units to generate DC voltages of 5V, 12V, 24V and 220V by stepping up or down, and finally switches the gears through a four-to-one switch; 5V is output as a USB auxiliary power supply and does not need to be switched.

[0019] Furthermore, the human-computer interaction module includes a display screen, touch buttons and knobs; the display screen is used to display power output voltage, power output current, signal output current, device temperature and operating status; the touch buttons include V set 、V out , S set and S ou t button.

[0020] Furthermore, the Vset The button function is to enter the power output voltage setting interface and automatically interrupt the current power output. At this time, the knob adjusts the preset output voltage. Note that the voltage is not output at this time.

[0021] When the preset voltage is determined, long press V out Press the button, the power output will be turned on again, and the output voltage will be the preset voltage.

[0022] S set The button is to enter the signal output current setting interface. Note that the signal output will not be interrupted at this time. At this time, the knob enters the signal current configuration state. If you press and hold S out Press the button. If the current state is signal output, the signal output will be turned off. Otherwise, the signal output will be turned on.

[0023] Furthermore, the composite multifunctional signal generating device also includes a current and voltage acquisition module for acquiring the current and voltage output by the power supply module, and transmitting the acquired current and voltage to the main control module after wave recording isolation and overvoltage and overcurrent protection.

[0024] Furthermore, an alloy resistor is connected in series with the load loop to implement load current sampling.

[0025] Furthermore, the composite multifunctional signal generating device also includes a wire reel, and the power supply cable adopts a wire reel.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] After the present invention adopts multiple power supplies and signal outputs, it can fully improve the current separation status of multiple power application modes during the use of field equipment and instruments and meters, and greatly improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A block diagram of the composition of a composite multifunctional signal generating device provided by an embodiment of the present invention;

[0029] Figure 2 This is the block diagram of the 4-20mA signal generator;

[0030] Figure 3 This is a circuit diagram for converting 5V to 24V;

[0031] Figure 4 This is a circuit diagram of a 4-20mA signal generator;

[0032] Figure 5a-5d This is a switching diagram of a four-to-one switch;

[0033] Figure 6 This is the high level total input power control circuit diagram;

[0034] Figure 7 It is a four-way switching circuit diagram;

[0035] Figure 8 The circuit diagram of 24V DC-DC;

[0036] Fig. 9 This is the circuit diagram of 12V DC-DC;

[0037] Fig.10 The circuit diagram of 5V DC-DC;

[0038] Fig.11 This is the circuit diagram of 220V DC-DC;

[0039] Fig.12 This is a display interface diagram of a liquid crystal display;

[0040] Fig.13 This is the minimum system circuit diagram of STM32F405RGT6;

[0041] Fig.14 This is the block diagram of the voltage and current acquisition module;

[0042] Fig.15 Overvoltage and overcurrent protection circuit diagram for voltage measurement;

[0043] Fig.16 This is the current sampling circuit diagram;

[0044] Fig.17 This is the circuit diagram of the resistor voltage divider;

[0045] Fig.18 This is the circuit diagram of the isolation amplifier;

[0046] Fig.19 This is the DC-DC isolated power supply application circuit diagram;

[0047] Fig. 20 It is the circuit diagram of voltage acquisition - differential to single-ended conversion;

[0048] Fig.21 This is the circuit diagram of current acquisition - differential to single-ended conversion;

[0049] Fig. 22 Active low-pass filter diagram for voltage and current acquisition;

[0050] Fig.23 This is the main program flow chart of the calibrator;

[0051] Fig.24 It is the flow chart for voltage, current and temperature acquisition;

[0052] Fig.25This is the voltage gear switching flow chart;

[0053] Fig.26 Configuration flow chart for the 4-20mA signal generator. DETAILED DESCRIPTION

[0054] Example:

[0055] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a signal connection; it can be directly connected, or indirectly connected through an intermediate medium, which can be said to be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The technical solution of the present invention is further explained below in conjunction with the accompanying drawings and embodiments.

[0056] See also Figure 1 The composite multifunctional signal generating device provided in this embodiment includes a main control module, a power supply module, a 4-20mA current signal generator module and a human-computer interaction module. The integrated composite design of the above modules ensures that a single device has multifunctional power output and signal output functions after being formed, and can achieve the purpose of being easy to carry, quick to use, and long-distance use.

[0057] Among them, the main control module is the core of the entire test device. It uses the embedded mixed-signal microprocessor STM32F405RGT6 as the main control core. Its main function is to control the output of the power supply and 4-20mA signal generator, and display parameters such as voltage, current, and temperature in real time on the human-computer interaction module. The setting of voltage and current is completed through knobs and buttons.

[0058] The main function of the 4-20mA current signal generator is to output a 4-20mA constant current signal. Figure 2 The block diagram is shown, which mainly consists of a 24V boost unit, a digital-to-analog converter DAC and a constant current source generator. The 24V boost unit is responsible for the power supply of the constant current source generator, the digital-to-analog converter DAC realizes the programmable voltage output, and the constant current source generator linearly converts the voltage output by the DAC into a constant current output.

[0059] like Figure 3-4 As shown in the figure, the DAC chip is AD5660, the resolution of AD5660 is 16 bits, the built-in reference voltage is 1.25V, and the output voltage range is 0-2.5V. The constant current source generator adopts the solution of XTR111+external PMOS current expansion, the maximum output current can reach 36mA, the accuracy can reach 0.015%, and it can provide the 5V regulated voltage required by AD5660.

[0060] The power supply module is responsible for power input, including the USB auxiliary power supply. It is mainly composed of an AC-DC 48V 1.35A power supply unit and multiple DC-DC power supply units. The AC-DC is responsible for converting the AC into a DC 48V voltage. This 48V voltage is used as the common input of multiple DC-DCs. It generates 5V, 12V, 24V and 220V DC voltages by stepping up or down, and finally switches gears through a four-choice switch. Among them, 5V is output as a USB auxiliary power supply and does not need to be switched. The AC-DC power supply unit is also used to directly output AC voltage, that is, the AC power is directly looped out after passing through the AC-DC power supply unit.

[0061] In order to ensure reliable gear switching, the solid-state relay added to the 48V power supply is used as the main switch. When the four-to-one switch switches gears, the MCU will pre-turn off the 48V power supply. After the four-to-one switch gears are switched, the MCU will turn on the 48V power supply again.

[0062] Because 48V is the total power supply for all DC-DC modules, all DC-DC modules have no output after being turned off. Therefore, during voltage switching, as shown in Figure 5-7, the four-to-one switch is not powered. This operation reduces the power demand for the four-to-one switch. Even if a mechanical relay is used, there will be no problem of excessive instantaneous current at the contacts that cannot be disconnected. In this way, an ordinary small relay can do the job, greatly saving circuit space.

[0063] Specifically, Figure 8-10 As shown, the 5V / 12V / 24V DC-DC uses the same BUCK switch step-down chip TPS54360 from TI.

[0064] The TPS54360 is a 60-V, 3.5-A step-down regulator with an integrated high-side MOSFET. The device can withstand load-dump pulses up to 65 V per ISO 7637. Current-mode control provides simple external compensation and flexible component selection. A low-ripple pulse-skipping mode reduces the supply current to 146 μA at no load. When the enable pin is pulled low, the shutdown supply current is reduced to 2 μA.

[0065] The undervoltage lockout of the TPS54360 is internally set to 4.3V, but can be increased using the enable pin. The device internally controls the output voltage startup ramp to control the startup process and eliminate overshoot.

[0066] The wide switching frequency range of the TPS54360 allows optimization of efficiency or external component size. Frequency foldback and thermal shutdown functions protect internal and external components from damage during overload conditions.

[0067] The 220V voltage output is significantly higher than the 48V voltage input, so a BOOST topology switching power supply design is adopted, using LM5022 from TI.

[0068] like Fig.11 As shown, the LM5022 device is a high voltage, low-side, N-channel MOSFET controller that is ideal for boost and SEPIC regulators. It contains all the functions required to implement a single-ended primary topology. The output voltage regulation is based on current mode control, which simplifies the design of loop compensation while providing inherent input voltage feedforward. The LM5022 includes a startup regulator and can operate over a wide input range of 6V to 60V. The PWM controller is designed for high-speed capabilities, including an oscillator frequency range of up to 2.2MHz and a total propagation delay of less than 100ns. Other features include an error amplifier, precision reference, line undervoltage lockout, cycle-by-cycle current limit, slope compensation, soft start, external synchronization capability, and thermal shutdown.

[0069] Specifically, the human-computer interaction module includes a display screen, four touch buttons and a knob. Fig.12 As shown, the display screen uses a 3.5-inch TFT screen with a resolution of 480x320. The screen interface is an SPI serial bus interface. Its main function is to display power output voltage, power output current, signal output current, device temperature and operating status. The operating status includes normal, overvoltage, overcurrent and overtemperature. The four touch buttons are Vset, Vout, Sset and Sou.

[0070] The Vset button function is to enter the power output voltage setting interface and automatically interrupt the current power output. At this time, the knob can adjust the preset output voltage. Note that the voltage is not output at this time.

[0071] When the preset voltage is determined, long press Vout to restart the power output. At this time, the output voltage is the preset voltage just now.

[0072] The Sset key is used to enter the signal output current setting interface. Please note that the signal output will not be interrupted at this time. At this time, the knob enters the signal current configuration state. If you press and hold Sout, if the current state is signal output, the signal output will be turned off, otherwise the signal output will be turned on.

[0073] The peripheral circuits of the main control module are as follows Fig.13 As shown, the core is STM32F405RGT6, which uses an external crystal oscillator of 8MHz as a reference and is internally multiplied to 168MHz for system operation.

[0074] In addition, the composite multifunctional signal generating device also includes a current and voltage acquisition module for acquiring the current and voltage output by the power supply module, and transmitting the acquired current and voltage to the main control module after wave recording isolation and overvoltage and overcurrent protection.

[0075] Specifically, the block diagram of the current and voltage acquisition module is as follows: Fig.14 As shown, the overvoltage and overcurrent protection circuit for voltage measurement is as follows Fig.15 As shown, the core is composed of PPTC and TVS tubes, the PPTC working current is 1A, and the tripping current is 2A. The TVS model is SMCJ250CA, the working voltage is 250V, and the breakdown voltage range is 279~309V.

[0076] like Fig.16 As shown in the figure, the current acquisition part uses a low-resistance resistor in series with the load loop to achieve load current sampling. Because the output voltage may be as high as 220V, the sampling resistor is placed on the low-voltage side to reduce the common-mode voltage requirement of the post-amplifier. At the same time, the sampling resistor should be a low-resistance alloy resistor. The low resistance can reduce the heating of the sampling resistor, thereby reducing the temperature drift of the sampling resistor and improving the current sampling accuracy.

[0077] The resistor voltage divider circuit is as follows Fig.17 As shown, the maximum measurement voltage is 250V. A 1MΩ high-impedance input terminal is formed by connecting multiple 1206-packaged resistors with a withstand voltage of 200V in series. Considering the load of the subsequent isolation amplifier of 28kΩ, the voltage division ratio is about 1000:1.

[0078] The high-voltage side of the voltage divider combination uses 499kΩ+499kΩ+1kΩ to form 999kΩ, and the 28kΩ equivalent measurement load and 1.02kΩ on the low-voltage side are equivalent to about 984Ω in parallel, and the voltage divider ratio is about 1000: 1. The voltage divider output uses 1nF filtering, and a 6V bidirectional TVS tube SMBJ6.0CA is used to clamp the voltage divider output.

[0079] Isolation amplifier circuit such as Fig.18 As shown, the core is the high-precision isolation amplifier AMC1200, with a silicon dioxide (SiO2) barrier with high magnetic field immunity isolating the output from the input. According to UL1577 and IEC60747-5-2 standards, the isolation barrier is certified to provide voltage isolation of up to 4000V peak.

[0080] AM1200 input and output are both differential, with high suppression of common mode noise, and has 8 times gain, which is very suitable for measuring slow and weak signals.

[0081] DC-DC isolated power supply such as Fig.19As shown, the integrated DC-DC isolation power supply module HLK-1D0505A is used as the core for the power supply of the isolation amplifier. In order to suppress the interference of the switching power supply, the LDO chip XC6206P502 is added to the front stage of the isolation amplifier power supply to reduce the measurement error.

[0082] The isolation amplifiers for differential to single-ended voltage acquisition and current acquisition both use AMC1200, so their outputs are differential signals, while the final acquired ADC is a single-ended interface, so a differential to single-ended circuit is required.

[0083] like Figure 20-21 As shown, the single-supply instrumentation amplifier AD623 is used for conversion. The AD623 is an instrumentation amplifier from ADI. It is an integrated single-supply or dual-supply instrumentation amplifier that provides rail-to-rail output swing when using a 3V to 12V supply voltage. It can be programmed through a single gain setting resistor and is configured in accordance with the 8-pin industrial standard pinout, giving users outstanding flexibility. When no external resistor is connected, the AD623 uses a unity gain configuration (G = 1); when an external resistor is connected, the AD623 can be programmed to achieve a maximum gain of 1000.

[0084] Improving the ac common-mode rejection ratio (CMRR) and increasing gain gives the AD623 excellent accuracy; since the CMRR remains stable up to 200Hz, line noise harmonics are suppressed. The AD623 has a wide input common-mode range and can amplify signals with common-mode voltages as low as 150mV below ground. The AD623 operates with bipolar and unipolar supplies and maintains excellent performance.

[0085] Voltage and current acquisition signals are susceptible to interference, such as Fig. 22 As shown, an active low-pass filter is added to the front end of the ADC, using a 4th-order Butterworth low-pass filter with a 3dB bandwidth of approximately 1KHz.

[0086] The filter op amp uses the OPA2188, which uses TI's proprietary auto-zero technology to provide low offset voltage (25μV, maximum) and approximately zero drift over time and temperature. These miniature, high-precision, low-quiescent current amplifiers provide high input impedance and rail-to-rail outputs with a swing within 15mV of the power rail. The input common-mode range includes the negative power rail, and single or dual power supplies can be used in the range of 4V to 36V (±2V to ±18V).

[0087] In addition, the device needs to be inspected. The main program flow chart of the calibrator is as follows: Fig.23The software program of the calibrator is written in C language, and uses the embedded system ucosIII to manage multi-tasks. After the compiler software is compiled, the executable file is generated and downloaded to the microcontroller STM32F405RGT6 for execution.

[0088] The voltage, current and temperature acquisition process is as follows: Fig.24 As shown, the voltage, current and temperature parameters are obtained by timing reading.

[0089] The voltage range switching process is as follows: Fig.25 As shown, the output voltage gear is switched by adopting the method of "first turn off and then turn on", so the safety is improved.

[0090] The configuration process of the 4-20mA current signal generator module is as follows Fig.26 As shown, the signal current to be output obtains the corresponding hexadecimal value according to the conversion formula, and finally is configured into the DAC chip through the SPI bus.

[0091] In addition, the device is also designed with a cable reel application structure. Combining the long-distance use characteristics of the original jack-type cable reel, a localized application design is carried out, and portability and reliability are comprehensively considered to ensure that the device is easy to carry, suitable in size, easy to place and collect, and the cable length is sufficient.

[0092] In summary, the present invention is a composite signal generating device based on the microcontroller STM32F405RGT6. On this basis, the present invention is mainly a multifunctional power supply that integrates a 4-20mA signal generator, has DC and AC power output, and comes with a wire reel device. It has 1 voltage output channel with adjustable gear, 1 fixed 1-way 5V 2A fixed voltage output channel, 1 AC output channel and 1-way 4-20mA signal generator. Information such as output voltage, current and equipment temperature is displayed on a 3.5-inch TFT LCD screen. The calibrator has buttons and knobs, which can flexibly adjust the output parameters. The power supply cable adopts a wire reel device, which can extend the power supply by 50m. Compared with the prior art, the present invention has the following technical advantages:

[0093] 1. The use of multiple power supplies and signal outputs can fully improve the separation status of multiple power application methods during the use of field equipment and instruments, and greatly improve work efficiency.

[0094] 2. The product is easy to carry and can be used over long distances, which completely eliminates the upper limit of the regional range of the workplace and ensures that there are no blind spots in the workplace when using the equipment.

[0095] 3. The voltage value can be intuitively perceived from the display screen. The visual experience can completely avoid damage to equipment and precision instruments caused by misuse, greatly improving the safety level of on-site work.

[0096] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite multifunctional signal generating device, characterized in that: It includes a main control module, a power supply module, a current signal generator module and a human-computer interaction module; among which, The main control module is used to control the output of the power supply module and the current signal generator, and display the parameters in real time on the human-computer interaction module; The current signal generator module is used to output a current constant current signal with a set range value; The power supply module is responsible for power input, including the USB auxiliary power supply, and is mainly composed of an AC-DC power supply unit and N DC-DC power supply units; the AC-DC power supply unit is responsible for converting alternating current into a direct current voltage, and the direct current voltage is used as a common input of the N DC-DC power supply units to generate different direct current voltages by stepping up or down, and finally switching the gears through the N-to-one switch; wherein a certain direct current voltage generated is output as a USB auxiliary power supply, and no switching is required, and N is a positive integer; The AC-DC power supply unit is also used to directly output an AC voltage; The current signal generator module is a 4-20mA signal generator that outputs a 4-20mA constant current signal, and includes a 24V boost unit, a digital-to-analog converter DAC, and a constant current source generator; the 24V boost unit is responsible for the power supply of the constant current source generator, the digital-to-analog converter DAC realizes programmable voltage output, and the constant current source generator linearly converts the voltage output by the DAC into a constant current output; The output end of the AC-DC power supply unit is provided with a solid-state relay as a main switch. When the N-to-one switch switches gears, the main control module turns off the AC-DC power supply unit in advance. After the N-to-one switch gears are switched, the main control module turns on the AC-DC power supply unit again to supply power; The human-computer interaction module includes a display screen, touch buttons and knobs; the display screen is used to display power output voltage, power output current, signal output current, device temperature and operating status; the touch buttons include V set 、V out , S set and S ou t button; The V set The button function is to enter the power output voltage setting interface and automatically interrupt the current power output. At this time, the knob adjusts the preset output voltage. Note that the voltage is not output at this time. When the preset voltage is determined, long press V out Press the button, the power output will be turned on again, and the output voltage will be the preset voltage just now; S set The button is to enter the signal output current setting interface. Note that the signal output will not be interrupted at this time. At this time, the knob enters the signal current configuration state. If you press and hold S out Press the button. If the current state is signal output, the signal output will be turned off. Otherwise, the signal output will be turned on.

2. The composite multifunctional signal generating device according to claim 1, characterized in that: During the voltage switching process, the N-to-one switch is not powered.

3. The composite multifunctional signal generating device according to claim 1 or 2, characterized in that: The AC-DC power supply unit converts the AC power into a DC 48V voltage, which is used as the common input of the four DC-DC power supply units to generate 5V, 12V, 24V and 220V DC voltages by stepping up or down, and finally switches the gears through a four-select-one switch; The 5V is used as USB auxiliary power output and does not need to be switched.

4. The composite multifunctional signal generating device according to claim 1, characterized in that: It also includes a current and voltage acquisition module, which is used to collect the current and voltage output by the power supply module, and transmit the collected current and voltage to the main control module after wave recording isolation and overvoltage and overcurrent protection.

5. The composite multifunctional signal generating device as claimed in claim 4, characterized in that: The load current sampling is realized by connecting alloy resistor in series with the load loop.

6. The composite multifunctional signal generating device as claimed in claim 1, characterized in that: It also includes a cable reel, and the power supply cable adopts the cable reel.

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