A signal conversion device

Abstract

This utility model discloses a signal conversion device, including: a control module and a current conversion module; the control module is connected to the current conversion module, and is configured to receive a square wave signal fed back from a controllable load, filter the square wave signal to generate a PWM signal; the current conversion module is configured to receive the PWM signal, convert the PWM signal into a current signal, and output it. This utility model proposes a signal conversion device that, through the filtering of the square wave signal fed back from the load by the control module, can effectively remove noise and interference components from the square wave signal, generating a stable PWM signal. The stable PWM signal provides a precise control basis for the subsequent current conversion module.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a signal conversion device. Background Technology

[0002] In fields such as industrial automation and equipment monitoring, the operating status of controllable loads (such as fans, pumps, and motors) is often fed back and controlled through specific signals. Traditionally, controllable loads often use square wave signals as feedback, the frequency and other characteristics of which are related to the load's operating parameters (such as speed and flow rate). However, square wave signals are susceptible to electromagnetic interference and line noise during actual transmission, leading to signal quality degradation and problems such as frequency fluctuations and noise intrusion. Furthermore, many devices in industrial control systems are better suited to standard current signals for data acquisition and control. Directly using square wave signals in such systems presents drawbacks such as signal type incompatibility, insufficient anti-interference capability, and susceptibility to distortion during long-distance transmission, making it difficult to meet the requirements for high-precision, long-distance, and interference-resistant signal transmission and control.

[0003] To solve the compatibility problem between square wave signals and industrial standard current signals, and to achieve accurate monitoring and stable control of the operating status of controllable loads, there is an urgent need for a device that can effectively process the square wave signals fed back by controllable loads and convert them into standard current signals. Utility Model Content

[0004] This invention provides a signal conversion device to address at least one defect in the prior art.

[0005] This utility model embodiment provides a signal conversion device, including:

[0006] Control module, current conversion module;

[0007] The control module is connected to the current conversion module. The control module is configured to receive a square wave signal from the controllable load and filter the square wave signal to generate a PWM signal.

[0008] The current conversion module is configured to receive the PWM signal, convert the PWM signal into a current signal, and output it.

[0009] Optionally, it may also include a gating module, which is connected to the control module;

[0010] The control module is configured to receive multiple square wave signals, and the gating module is configured to set the control module to receive a specified square wave signal.

[0011] Optionally, it may also include an indicator module, which is connected to the control module;

[0012] The indicator module is used to generate a corresponding indicator signal when the square wave signal of the specified path is received.

[0013] Optionally, the current conversion module includes a current conversion chip, which is used to output a 4-20mA current signal according to the duty cycle of the PWM signal.

[0014] Optionally, the control module is configured to receive six of the square wave signals;

[0015] The controllable load includes fans and / or pumps.

[0016] Optionally, the gating module includes a DIP switch.

[0017] Optionally, a power supply module may also be included, which is configured to supply power to the control module and the current conversion module.

[0018] Optionally, the power module is configured to input 24V DC power.

[0019] Optionally, the indicator module includes a plurality of LEDs, with each LED corresponding to one of the square wave signals.

[0020] Optionally, the signal conversion device is integrated onto a single PCB board.

[0021] Compared with existing technologies, the advantages of this invention are as follows: This invention proposes a signal conversion device, which is equipped with a control module and a current conversion module. The control module filters the square wave signal fed back from the load, effectively removing noise and interference components from the square wave signal and generating a stable PWM signal. The stable PWM signal provides precise control for the subsequent current conversion module, making the current conversion process more accurate and the output current signal more precise, which can meet the stringent signal accuracy requirements of industrial control and other scenarios. Attached Figure Description

[0022] Figure 1 This is a block diagram of the signal conversion device in the embodiment;

[0023] Figure 2 This is a schematic diagram of the current conversion module circuit in the embodiment;

[0024] Figure 3 This is a block diagram of another signal conversion device in the embodiment;

[0025] Figure 4 This is a schematic diagram of the power input circuit in the embodiment;

[0026] Figure 5 This is a schematic diagram of the DC-DC conversion circuit in the embodiment;

[0027] Figure 6 This is a schematic diagram of the control chip in the embodiment;

[0028] Figure 7 This is a schematic diagram of the square wave signal input port filter circuit in the embodiment;

[0029] Figure 8 This is a schematic diagram of the indicator circuit in the embodiment;

[0030] Figure 9 This is a schematic diagram of the DIP switch circuit in the embodiment;

[0031] Figure 10 This is a schematic diagram of the signal conversion curve in the embodiment. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0033] Figure 1 This is a block diagram of the signal conversion device in the embodiment, for reference. Figure 1 The signal conversion device includes: a control module 100 and a current conversion module 200.

[0034] The control module 100 is connected to the current conversion module 200. The control module 100 is configured to receive the square wave signal fed back by the controllable load 1 and filter the square wave signal to generate a PWM signal.

[0035] The current conversion module 200 is configured to receive PWM signals, convert the PWM signals into current signals, and output them.

[0036] In this solution, the control module 100 may include a microcontroller unit (MCU). The GPIO pin of the MCU can be configured to a timer input capture mode. The GPIO pin is connected to the square wave output terminal of the controllable load. The MCU is configured to capture the rising / falling edge time difference of the square wave signal through a timer, and then calculate the frequency of the square wave signal.

[0037] In this scheme, when the frequency of the square wave signal fluctuates, filtering can stabilize the frequency of the square wave signal, thereby generating a stable PWM signal. The filtering algorithm can employ mean filtering, low-pass filtering, etc.

[0038] For example, in this solution, a filtering algorithm is configured in the MCU. A sliding buffer (such as an array) can be configured in the MCU. After each frequency value is captured, the buffer is updated in a first-in-first-out manner. The stable frequency is calculated by the mean filtering formula, and then a PWM signal with the corresponding duty cycle is generated.

[0039] In this scheme, based on the filtered stable frequency value, the comparison value required for the output PWM signal is obtained according to a specific calculation rule. The calculated comparison value is loaded into the timer's comparison register, and the timer outputs a PWM signal with the corresponding duty cycle based on this value.

[0040] In this solution, to ensure stable system operation and accurate subsequent processing, the calculated input frequency is limited. Frequency values ​​exceeding the set range are adjusted to the maximum or minimum allowable value.

[0041] For example, in this solution, the current conversion module 200 may include a digital-to-analog conversion unit and an operational amplifier unit. The digital-to-analog conversion unit is configured to receive PWM signals and output analog voltage signals; the operational amplifier unit is configured to convert analog voltage signals into current signals.

[0042] This embodiment proposes a signal conversion device, which includes a control module and a current conversion module. The control module filters the square wave signal fed back from the load, effectively removing noise and interference components to generate a stable PWM signal. This stable PWM signal provides precise control for the subsequent current conversion module, making the current conversion process more accurate and the output current signal more precise, meeting the stringent signal accuracy requirements of industrial control and other scenarios.

[0043] Based on any of the aforementioned schemes, in one possible implementation, the signal conversion device further includes a gating module, which is connected to the control module.

[0044] The control module is configured to receive multiple square wave signals, and the gating module is configured to set the control module to receive a specified square wave signal.

[0045] In this scheme, the gating module is used to select the channel of multiple square wave signals, so that the control module only processes the selected specified signal.

[0046] For example, in this solution, the gating module may include an analog switch chip, the input terminal of the analog switch chip is configured to receive a square wave signal, the output terminal of the analog switch chip is connected to the control module, and the control terminal of the analog switch chip is connected to the control module.

[0047] The control module can be configured to output a specified coded signal, which controls the level of the control terminal of the analog switch chip, thereby enabling one or more specified paths in the analog switch chip to conduct.

[0048] In this scheme, the selection module enables the selection of square wave signal paths, making the signal conversion device suitable for scenarios involving the processing of multiple square wave signals and facilitating the conversion of feedback signals for multiple loads.

[0049] Based on any of the aforementioned solutions, in one possible implementation, the signal conversion device further includes an indicator module, which is connected to the control module.

[0050] The indicator module is used to generate a corresponding indicator signal when a square wave signal of a specified path is received.

[0051] In this solution, the indicator module can include indicator lights. The high / low level output of the GPIO pin of the configuration control module controls the on / off state of the indicator lights. When the configuration control module determines that the path of the Nth square wave signal is open, it drives the Nth indicator light to light up.

[0052] In this solution, the path of the connected square wave signal can be quickly determined through the indicator module. During operation and maintenance, it is convenient to confirm the currently monitored load path and avoid misoperation.

[0053] Based on any of the aforementioned schemes, in one possible implementation, the current conversion module includes a current conversion chip, which is used to output a 4-20mA current signal according to the duty cycle of the PWM signal.

[0054] Figure 2 This is a circuit schematic of the current conversion module in the embodiment, for reference. Figure 2 In one possible implementation, the current conversion chip U2 can be a GP8102S. U2 is also equipped with peripheral circuitry, which includes a first operational amplifier OP2A, a second operational amplifier OP2B, a third operational amplifier OP2C, and a transistor Q4.

[0055] In this scheme, Fan_Out_2 serves as the receiving end of the PWM signal output by the control module, and IOUT_Fan_2 serves as the current signal output end of the current conversion module (outputting a 4-20mA current signal).

[0056] In this design, the first operational amplifier OP2A, the second operational amplifier OP2B, the third operational amplifier OP2C, and the sampling resistor RS2 constitute a voltage feedback circuit. The output of the third operational amplifier OP2C is connected to the feedback pin FB of U2. U2 adjusts the output of the pin IOUT according to the feedback voltage received from FB.

[0057] In this design, the first operational amplifier OP2A, the second operational amplifier OP2B, and the third operational amplifier OP2C can all be based on the LM324 model.

[0058] In this scheme, transistor Q4 operates in the amplification region, and the output signal of IOUT acts on the base of transistor Q4, thereby realizing the current control of the collector-emitter current of transistor Q4, and thus realizing the control of the output current of IOUT_Fan_2 terminal.

[0059] In this design, capacitors C10 and C9 and resistor R14 form a filter circuit to filter out noise from the power supply pin V5V; resistor R15 serves as a current-limiting resistor; a unidirectional TVS is used for overvoltage protection; capacitor C8 is used for filtering; and resistors R11, R10, R13, and R12 are standard settings for OP2C.

[0060] In this solution, using a current conversion chip to design the current conversion module can reduce design costs while improving the accuracy of the output current signal.

[0061] Based on any of the aforementioned schemes, in one possible implementation, the control module is configured to receive six square wave signals; the controllable load includes a fan and / or a pump.

[0062] In this solution, during operation, the fan and pump typically use built-in sensors or circuits to feedback their operating status (such as speed and operating frequency) in the form of square wave signals. The frequency of the square wave signal is often related to the operating parameters of the equipment; for example, the higher the fan speed, the higher the frequency of the feedback square wave signal may be.

[0063] In this solution, the control module is configured to receive square wave signals from multiple fans and / or pumps, enabling monitoring of the operating status of multiple loads and providing reliable data support for subsequent equipment control and other functions.

[0064] Based on any of the aforementioned schemes, in one possible implementation, the gating module includes a DIP switch.

[0065] In this exemplary solution, the DIP switch can be a manual coded switch. By toggling the switch's position, the internal circuit connection state can be changed, thereby outputting different coded combinations. Each DIP switch corresponds to one binary bit, and multiple DIP switches combined together can form different binary codes, which can be used to represent the square wave signal channel to be selected.

[0066] For example, in this solution, the gating module is connected to the control module. When the user sets the channel to be selected through the DIP switch, the gating module conducts the corresponding square wave signal path according to the encoding state of the DIP switch and transmits the square wave signal to the control module.

[0067] In this scheme, a DIP switch is used to select the square wave signal path, which can conveniently and reliably realize the function of selecting a specified square wave signal, providing a foundation for the flexible application of signal conversion devices.

[0068] Based on any of the aforementioned solutions, in one possible implementation, the signal conversion device further includes a power supply module configured to supply power to the control module and the current conversion module.

[0069] In this design, the power supply module is connected to the control module and the current conversion module. The output voltage of the power supply module is designed according to the power supply requirements of the control module and the current conversion module.

[0070] In this solution, the power supply module is configured to provide a continuous and stable power supply to the control module and the current conversion module, so as to ensure that the control module can accurately receive and process square wave signals, and the current conversion module can accurately convert the processed signals into the required current signal output.

[0071] For example, in this solution, the power module may include a power interface, a linear regulator, and a power conversion circuit. The power interface may be a DC power socket for connecting an external power adapter. The linear regulator converts a 12-24V input voltage to 5V. The power conversion circuit converts the 5V voltage to 3.3V.

[0072] Based on any of the aforementioned solutions, in one possible implementation, the power module is configured to input 24V DC power.

[0073] Based on any of the aforementioned schemes, in one possible implementation, the indicator module includes several LEDs, with each LED corresponding to a square wave signal.

[0074] Based on any of the aforementioned solutions, in one possible implementation, the signal conversion device is integrated onto a single PCB board.

[0075] Figure 3 This is a block diagram of another signal conversion device in the embodiment, see reference. Figure 3 In this scheme, the device includes: control module 100, current conversion module 200, gating module 300, indicator module 400, and power supply module 500.

[0076] The control module 100 is connected to the current conversion module 200, the gating module 300, the indicator module 400, and the power supply module 500.

[0077] Figure 4 This is a schematic diagram of the power input circuit in the embodiment. Figure 5 This is a schematic diagram of the DC-DC conversion circuit in the embodiment, for reference. Figure 4 and Figure 5 In this solution, the power module 500 may include a power input circuit and a DC-DC conversion circuit.

[0078] refer to Figure 4 The power input circuit includes interface CN1, inductor J1, fuses F1 and F2, diodes Q1 and D1, and capacitor C1. Interface CN1 is used to connect to 24VDC; diode Q1 is used for bidirectional reverse connection protection; diode D1 is used for overvoltage protection; capacitor C1 is used for filtering; fuses F1 and F2 are used for overcurrent protection; and inductor J1 is used for common-mode rejection.

[0079] refer to Figure 5 The DC-DC conversion circuit includes a power chip Q9, which can be an LM2595S. The capacitors C26, C27, and C25, the inductor L1, the resistor R48, and the clamping diode D12 are standard peripheral circuits for the power chip Q9. The specific connection methods and functions will not be detailed here.

[0080] In this scheme, the output voltage VCC of the power chip Q9 is used to power the control module 100, and the output VIN of the power input circuit is used to power the current conversion module 200.

[0081] Figure 6 This is a schematic diagram of the control chip in the embodiment, for reference. Figure 6 In this solution, the control module 100 includes a control chip, which is model ES8H0183FLLP. The control chip is configured to monitor the feedback square wave signals (Fac_In_1~Fac_In_4) of the four fans and the feedback square wave signals (Pumb_In_1, Pumb_In_2) of the two pumps.

[0082] In this design, a filter circuit is configured at the input of the feedback square wave signal. Figure 7 This is a schematic diagram of the square wave signal input port filter circuit in the embodiment, for reference. Figure 7 Taking the feedback square wave signal of the second fan as an example, the filtering circuit includes resistor R9 and capacitor C29. The feedback square wave signal Fan_In_2 of the second fan is input into the control module 100 after passing through the filtering circuit.

[0083] Figure 8 This is a schematic diagram of the indicator circuit in the embodiment, for reference. Figure 8 The indicator module 400 includes six light-emitting diodes (D13, D9, D14 to D17), and each light-emitting diode is equipped with a current-limiting resistor (R55, R45, R46, R56, R57, R58). Each light-emitting diode is connected to the LED1 to LED6 pins of the control module 100.

[0084] Figure 9 This is a schematic diagram of the DIP switch circuit in the embodiment, for reference. Figure 9 The DIP switch circuit includes a DIP switch SW1, which is configured with six DIP switches. Each DIP switch path is configured with a resistor (R49 to R54). The DIP switch SW1 is connected to the KEY1 to KEY6 pins of the control module 100.

[0085] In this scheme, the control module 100 is also equipped with clock pin ISCK0, data pin ISDA0, reset pin MRSTN, and communication pins RXD1 and TXD1.

[0086] In this solution, the current conversion module 200 includes six current conversion circuits, and the design of each current conversion circuit is as follows: Figure 2 As shown, the current conversion circuit is connected to the control module 100 through Fac_In_1~Fac_In_4, Pumb_In_1, and Pumb_In_2 respectively. The specific connection method and working principle will not be described in detail.

[0087] In this solution, the power module 500 is designed as follows: Figure 4 , Figure 5 As shown, the specific connection method and working principle will not be described in detail.

[0088] In this scheme, the DIP switch SW1 controls whether the conversion function of the corresponding channels in Fac_In_1~Fac_In_4, Pumb_In_1, and Pumb_In_2 is enabled, and the corresponding LED in the configuration indicator module 400 indicates whether the conversion function of the corresponding channel is enabled.

[0089] In this scheme, the control module 100 is configured to receive the feedback square wave signal and filter it. When the frequency of the input feedback square wave signal fluctuates, it can output a relatively stable current signal.

[0090] In this scheme, the configuration control module 100 uses a timer to capture and put the calculated frequency value into a sliding buffer. It performs mean filtering on all data in the buffer in real time, and generates a PWM signal from the filtered data and outputs it to the current conversion module 200.

[0091] Figure 10 This is a schematic diagram of the signal conversion curve in the embodiment, for reference. Figure 10 In this solution, the current conversion module 200 can convert the input PWM into a 4-20mA current signal and output it at the output port. The minimum frequency corresponds to an output current of 4mA, and the maximum frequency corresponds to an output current of 20mA. When the frequency is between the maximum and minimum, the output current is calculated and output according to a linear relationship.

[0092] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A signal conversion device, characterized in that, include: Control module, current conversion module; The control module is connected to the current conversion module. The control module is configured to receive a square wave signal from the controllable load and filter the square wave signal to generate a PWM signal. The current conversion module is configured to receive the PWM signal, convert the PWM signal into a current signal, and output it.

2. The signal conversion device as described in claim 1, characterized in that, It also includes a gating module, which is connected to the control module; The control module is configured to receive multiple square wave signals, and the gating module is configured to set the control module to receive a specified square wave signal.

3. The signal conversion device as described in claim 2, characterized in that, It also includes an indicator module, which is connected to the control module; The indicator module is used to generate a corresponding indicator signal when the square wave signal of the specified path is received.

4. The signal conversion device as described in claim 1, characterized in that, The current conversion module includes a current conversion chip, which is used to output a 4-20mA current signal according to the duty cycle of the PWM signal.

5. The signal conversion device as described in claim 2, characterized in that, The control module is configured to receive six of the square wave signals; The controllable load includes fans and / or pumps.

6. The signal conversion device as described in claim 2, characterized in that, The gating module includes a DIP switch.

7. The signal conversion device as described in claim 1, characterized in that, It also includes a power module configured to supply power to the control module and the current conversion module.

8. The signal conversion device as described in claim 7, characterized in that, The power module is configured to input 24V DC power.

9. The signal conversion device as described in claim 3, characterized in that, The indicator module includes several LEDs, and each LED corresponds to one of the square wave signals.

10. The signal conversion device according to any one of claims 1 to 9, characterized in that, The signal conversion device is integrated on a single PCB board.

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