Full-isolation signal conditioner

Abstract

The invention discloses a full-isolation signal conditioner which comprises a power supply module, and an input module, a programmable signal configuration module and an output module which are connected with the power supply module, isolation modules are arranged between the input module and the programmable signal configuration module, between the programmable signal configuration module and the output module and between the power supply module; the power supply module comprises an open-loop power supply and a primary side noise feedback module; the open-loop power supply adopts a flyback topological structure; the primary side noise feedback module comprises a noise sampling circuit and a digital controller, and the isolation module comprises at least one independent isolation unit. The structure of the signal isolation conditioner is more flexible and simpler, and an integrated solution of high isolation, low crosstalk and multi-signal type dynamic configuration is realized on the premise of low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic signal processing, and in particular to a fully isolated signal conditioner. Background Art

[0002] A signal conditioner is an electronic device used to process and condition the raw signal output from a sensor or device. Its primary purpose is to convert the signal into a standardized form suitable for subsequent processing, transmission, or recording. It is widely used in industrial automation, test and measurement, medical equipment, and other fields, and is a key component in data acquisition and control systems. Traditional signal isolation conditioners often use closed-loop power control technology. While highly stable, this technology is rigid and expensive, requiring complex feedback circuits and precision components. This leads to high costs and inflexible adaptation to single, dual, or mixed signal channels. Existing multi-channel products use a single transformer integrating multiple windings, resulting in severe electromagnetic coupling between channels. Test data shows that when the input signal frequency is 1kHz, the crosstalk suppression rate between adjacent channels is only 28dB, which cannot meet the requirements of precision industrial scenarios. Conditioners that rely on analog circuits for signal conversion struggle to support digital configuration, and switching between signal types requires hardware modifications, similarly limiting flexibility. Summary of the Invention

[0003] The object of the present invention is to provide a fully isolated signal conditioner that can simultaneously achieve high isolation, low crosstalk, and dynamic configuration of multiple signal types.

[0004] The present invention provides a fully isolated signal conditioner, comprising a power module, an input module, a programmable signal configuration module and an output module connected to the power module;

[0005] Isolation modules are provided between the input module and the programmable signal configuration module, between the programmable signal configuration module and the output module, and the power module;

[0006] The power supply module includes an open-loop power supply and a primary noise feedback module; the open-loop power supply adopts a flyback topology; the primary noise feedback module includes a noise sampling circuit and a digital controller; the primary noise feedback module dynamically adjusts the power supply duty cycle through the feedback algorithm of Formula I;

[0007]

[0008] Among them, is the adjusted duty cycle, is the reference duty cycle, is the proportional coefficient, is the collected primary noise voltage, is the preset reference voltage, and is the integral coefficient;

[0009] The isolation module includes at least one independent isolation unit.

[0010] Furthermore, the flyback topology structure of the fully isolated signal conditioner of the present invention includes an input rectifier and filter circuit, a flyback transformer, a switch tube, an output rectifier and filter circuit, and a drive circuit;

[0011] The input rectifier and filter circuit converts AC power into DC power, which is then connected to the drain of the switching tube through the primary winding. The source of the switching tube is grounded, and the gate of the switching tube is driven by the PWM signal output by the controller. The drive circuit obtains initial power supply through the starting resistor and continuously supplies power after rectification and filtering by the auxiliary winding of the transformer. The secondary winding of the flyback transformer provides a stable DC voltage to the load through the output rectifier and filter circuit.

[0012] The switching frequency of the flyback topology is 50 kHz to 200 kHz.

[0013] Furthermore, the noise sampling circuit of the primary side noise feedback module of the fully isolated signal conditioner of the present invention includes a differential amplifier and an isolated analog-to-digital converter; the digital controller calculates the duty cycle compensation amount in real time based on the feedback algorithm and outputs it to the drive circuit via a pulse width modulation signal;

[0014] The noise sampling circuit obtains a noise signal from the primary sampling resistor of the power module and outputs it to the positive and negative input terminals of the differential amplifier, converting the noise signal into a differential signal input; the differential amplifier filters out low-frequency ripple and high-frequency interference through an internal or external bandpass filter, and then outputs the signal to the analog input channel of the isolated analog-to-digital converter through a programmable gain adjustment module; the digital output terminal of the isolated analog-to-digital converter is connected to the digital controller.

[0015] Furthermore, the independent isolation unit of the fully isolated signal conditioner of the present invention includes any one or more combinations of transformer isolation, optical coupling isolation, magnetic coupling isolation, and capacitive isolation.

[0016] Furthermore, the transformer isolation of the fully isolated signal conditioner of the present invention includes a transformer and a magnetic shielding structure;

[0017] The transformer core is encapsulated with Permalloy, with a withstand voltage rating of no less than 1500VAC, and the physical isolation distance between adjacent transformers is greater than 5mm.

[0018] Furthermore, the input signal of the input module of the fully isolated signal conditioner of the present invention includes any one or more combinations of 2 / 3 / 4-wire 4-20mA current, 0-10V / ±5V voltage, PT100 / PT1000 temperature, and 24V DC switch quantity.

[0019] Furthermore, the output signal of the output module of the fully isolated signal conditioner of the present invention includes any one or more combinations of 0-20mA current, 0-5V / ±10V voltage, and RS-485 / Modbus RTU digital protocol.

[0020] Furthermore, when the independent isolation unit of the output module of the fully isolated signal conditioner of the present invention is configured as a single channel, the core of the transformer is selected to be EE16 size, and the number of turns of the primary winding is 40-60 turns.

[0021] Furthermore, when the independent isolation unit of the output module of the fully isolated signal conditioner of the present invention is configured with dual channels, the core of the transformer is selected to be EE20 size, the number of turns of the primary winding is 50-70 turns, and the secondary winding is wound with double-layer shielded wire.

[0022] Furthermore, the programmable signal configuration module of the output module of the fully isolated signal conditioner of the present invention includes a multi-channel input interface, a programmable gain amplifier, a switchable filter network, an analog-to-digital converter, a digital control unit and a multi-protocol output interface;

[0023] After passing through the protection circuit, the input signal enters the programmable gain amplifier for amplitude adjustment, then passes through a digitally controlled filter to filter out noise, and is then converted into a digital signal by an analog-to-digital converter. The digital control unit dynamically configures the signal path and parameters based on a preset algorithm or external instructions, and finally outputs the target signal through the digital-to-analog converter.

[0024] The signal configuration module switches the signal type through external control instructions, and the switching time is less than 1 second;

[0025] The configuration logic of the signal configuration module works in conjunction with the primary side noise feedback module to ensure that the load regulation rate of the open-loop power supply module remains less than ±1% during the signal type switching process.

[0026] The signal configuration module implements configuration logic through FPGA or host computer software, supporting linear mapping of input and output signals. For example, it can perform segmented fitting calibration of temperature sensors with an error of less than 0.05°C; de-jitter processing of switching signals with a de-jitter time configurable to 10ms; and an adjustable baud rate range of the digital protocol from 4800bps to 115200bps.

[0027] Furthermore, the fully isolated signal conditioner of the present invention also includes a high withstand voltage application mode, wherein:

[0028] The transformer's withstand voltage rating is increased to 2000VAC, and the creepage distance is greater than 8mm;

[0029] The feedback loop delay of the noise sampling circuit is less than 2 μs.

[0030] The fully isolated signal conditioner described in the present invention has the following beneficial effects:

[0031] The fully isolated signal conditioner described in this invention flexibly implements signal input, output, and power isolation. This is particularly useful for isolating multiple inputs and outputs in multi-channel products, such as single-input, two-output, or dual-input, two-output systems. With an isolation withstand voltage of 1500VAC, it isolates field signals from system signals, and from each other, suppressing and isolating interference and ensuring stable system operation.

[0032] This open-loop power supply, combined with a flyback topology, uses transformer isolation. Single-channel products only require one transformer, while dual-channel products require two. Primary-side noise feedback technology is also used for load compensation, adjusting the duty cycle for optimal load regulation.

[0033] In summary, the fully isolated signal conditioner of the present invention effectively blocks ground loop current and common mode interference through the fully isolated design of the input module, programmable signal configuration module and output module, combined with multiple types of isolation units (transformer, optocoupler, magnetic coupler, etc.), significantly improving the anti-electromagnetic interference capability and safety of the industrial site. The programmable signal configuration module supports adaptive processing of multiple signal types (such as 4-20mA, PT100, ±5V voltage, etc.), and realizes high-precision linearization and standardized output of sensor signals by dynamically switching gain, filtering algorithm and output protocol, meeting the flexible adaptation requirements of complex industrial scenarios. In addition, the open-loop power supply design based on primary side noise feedback solves the defect of poor load regulation rate of traditional flyback open-loop power supply by real-time acquisition of switching tube noise and dynamic compensation of duty cycle, thereby reducing cost and ensuring power supply stability.

[0034] The structure of the signal isolation conditioner described in the present invention becomes more flexible and simple, and an integrated solution of high isolation, low crosstalk, and dynamic configuration of multiple signal types is achieved at a low cost. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail. The embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the specific implementation method, they shall be carried out according to conventional conditions or conditions provided by the manufacturer.

[0036] The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. The terms used in the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. Specific implementation method one:

[0038] A fully isolated signal conditioner comprises a power module, an input module, a programmable signal configuration module and an output module connected to the power module;

[0039] Isolation modules are provided between the input module and the programmable signal configuration module, between the programmable signal configuration module and the output module, and the power module;

[0040] The power supply module includes an open-loop power supply and a primary noise feedback module; the open-loop power supply adopts a flyback topology; the primary noise feedback module includes a noise sampling circuit and a digital controller; the primary noise feedback module dynamically adjusts the power supply duty cycle through the feedback algorithm of Formula I;

[0041]

[0042] Among them, is the adjusted duty cycle, is the reference duty cycle, is the proportional coefficient, is the collected primary noise voltage, is the preset reference voltage, and is the integral coefficient;

[0043] The isolation module includes at least one independent isolation unit.

[0044] In other embodiments, the flyback topology structure includes an input rectifier and filter circuit, a flyback transformer, a switch tube, an output rectifier and filter circuit, and a drive circuit;

[0045] The input rectifier and filter circuit converts AC power into DC power, which is then connected to the drain of the switching tube through the primary winding. The source of the switching tube is grounded, and the gate of the switching tube is driven by the PWM signal output by the controller. The drive circuit obtains initial power supply through the starting resistor and continuously supplies power after rectification and filtering by the auxiliary winding of the transformer. The secondary winding of the flyback transformer provides a stable DC voltage to the load through the output rectifier and filter circuit.

[0046] The switching frequency of the flyback topology is 50 kHz to 200 kHz.

[0047] In other embodiments, the noise sampling circuit of the primary noise feedback module includes a differential amplifier and an isolated analog-to-digital converter; the digital controller calculates the duty cycle compensation amount in real time based on the feedback algorithm and outputs it to the drive circuit via a pulse width modulation signal;

[0048] The noise sampling circuit obtains a noise signal from the primary sampling resistor of the power module and outputs it to the positive and negative input terminals of the differential amplifier, converting the noise signal into a differential signal input; the differential amplifier filters out low-frequency ripple and high-frequency interference through an internal or external bandpass filter, and then outputs the signal to the analog input channel of the isolated analog-to-digital converter through a programmable gain adjustment module; the digital output terminal of the isolated analog-to-digital converter is connected to the digital controller.

[0049] In other embodiments, the independent isolation unit includes any one or more combinations of transformer isolation, optical coupling isolation, magnetic coupling isolation, and capacitive isolation.

[0050] In other embodiments, the transformer isolation includes a transformer and a magnetic shielding structure;

[0051] The transformer core is encapsulated with Permalloy, with a withstand voltage rating of no less than 1500VAC, and the physical isolation distance between adjacent transformers is greater than 5mm.

[0052] In other embodiments, the input signal of the input module includes any one or more combinations of 2 / 3 / 4-wire 4-20mA current, 0-10V / ±5V voltage, PT100 / PT1000 temperature, and 24V DC switch value.

[0053] In other embodiments, the output signal of the output module includes any one or more combinations of 0-20 mA current, 0-5 V / ±10 V voltage, and RS-485 / Modbus RTU digital protocol.

[0054] In other embodiments, when the independent isolation unit is configured with a single channel, the transformer core is of EE16 size, and the number of turns of the primary winding is 40-60 turns.

[0055] In other embodiments, when the independent isolation unit is configured with dual channels, the transformer core is of EE20 size, the number of turns of the primary winding is 50-70 turns, and the secondary winding is wound with double-layer shielded wire.

[0056] In other embodiments, the programmable signal configuration module includes a multi-channel input interface, a programmable gain amplifier, a switchable filter network, an analog-to-digital converter, a digital control unit, and a multi-protocol output interface;

[0057] After passing through the protection circuit, the input signal enters the programmable gain amplifier for amplitude adjustment, then passes through a digitally controlled filter to filter out noise, and is then converted into a digital signal by an analog-to-digital converter. The digital control unit dynamically configures the signal path and parameters based on a preset algorithm or external instructions, and finally outputs the target signal through the digital-to-analog converter.

[0058] The signal configuration module switches the signal type through external control instructions, and the switching time is less than 1 second;

[0059] The configuration logic of the signal configuration module works in conjunction with the primary side noise feedback module to ensure that the load regulation rate of the open-loop power supply module remains less than ±1% during the signal type switching process.

[0060] In other embodiments, the fully isolated signal conditioner of the present invention further includes a high voltage withstand application mode, wherein:

[0061] The transformer's withstand voltage rating is increased to 2000VAC, and the creepage distance is greater than 8mm;

[0062] The feedback loop delay of the noise sampling circuit is less than 2 μs.

[0063] Example 1:

[0064] A fully isolated signal conditioner comprises a power module, an input module, a programmable signal configuration module and an output module connected to the power module;

[0065] Isolation modules are provided between the input module and the programmable signal configuration module, between the programmable signal configuration module and the output module, and the power module;

[0066] The power supply module includes an open-loop power supply and a primary noise feedback module; the open-loop power supply adopts a flyback topology; the primary noise feedback module includes a noise sampling circuit and a digital controller; the primary noise feedback module dynamically adjusts the power supply duty cycle through the feedback algorithm of Formula I;

[0067]

[0068] Among them, is the adjusted duty cycle, is the reference duty cycle, is the proportional coefficient, is the collected primary noise voltage, is the preset reference voltage, and is the integral coefficient;

[0069] The isolation module includes at least one independent isolation unit.

[0070] In this embodiment 1, the flyback topology structure includes an input rectifier filter circuit, a flyback transformer, a switch tube, an output rectifier filter circuit, and a drive circuit;

[0071] The input rectifier and filter circuit converts AC power into DC power, which is then connected to the drain of the switching tube through the primary winding. The source of the switching tube is grounded, and the gate of the switching tube is driven by the PWM signal output by the controller. The drive circuit obtains initial power supply through the starting resistor and continuously supplies power after rectification and filtering by the auxiliary winding of the transformer. The secondary winding of the flyback transformer provides a stable DC voltage to the load through the output rectifier and filter circuit.

[0072] In this embodiment 1, the switching frequency of the flyback topology structure is 100 kHz, and the primary side sampling resistor is 1 ohm.

[0073] The noise sampling circuit of the primary noise feedback module includes a differential amplifier and an isolated analog-to-digital converter; the digital controller calculates the duty cycle compensation amount in real time based on the feedback algorithm and outputs it to the drive circuit through a pulse width modulation signal;

[0074] The noise sampling circuit obtains a noise signal from the primary sampling resistor of the power module and outputs it to the positive and negative input terminals of the differential amplifier, converting the noise signal into a differential signal input; the differential amplifier filters out low-frequency ripple and high-frequency interference through an internal or external bandpass filter, and then outputs the signal to the analog input channel of the isolated analog-to-digital converter through a programmable gain adjustment module; the digital output terminal of the isolated analog-to-digital converter is connected to the digital controller.

[0075] The independent isolation unit includes any one or more combinations of transformer isolation, optical coupling isolation, magnetic coupling isolation, and capacitive isolation.

[0076] The transformer isolation includes a transformer and a magnetic shielding structure;

[0077] The transformer core is encapsulated with Permalloy, with a withstand voltage rating of no less than 1500VAC, and the physical isolation distance between adjacent transformers is greater than 5mm.

[0078] The input signal of the input module includes any one or more combinations of 2 / 3 / 4-wire 4-20mA current, 0-10V / ±5V voltage, PT100 / PT1000 temperature, and 24V DC switch value.

[0079] The output signal of the output module includes any one or more combinations of 0-20mA current, 0-5V / ±10V voltage, and RS-485 / Modbus RTU digital protocol.

[0080] The programmable signal configuration module includes a multi-channel input interface, a programmable gain amplifier, a switchable filter network, an analog-to-digital converter, a digital control unit and a multi-protocol output interface;

[0081] After passing through the protection circuit, the input signal enters the programmable gain amplifier to adjust the amplitude, then passes through the digital control filter to filter out noise, and is then converted into a digital signal by the analog-to-digital converter. The digital control unit dynamically configures the signal path and parameters according to the preset algorithm or external instructions, and finally outputs the target signal through the digital-to-analog converter.

[0082] In this embodiment 1, the independent isolation unit is configured with dual channels, the transformer core is of EE20 size, the number of turns of the primary winding is 50-70 turns, and the secondary winding is wound with double-layer shielded wire.

[0083] In this embodiment 1, the isolated analog-to-digital converter adopts ADS1115, and the digital controller adopts STM32F407 microcontroller to implement PID closed-loop control.

[0084] The signal conditioning process is as follows:

[0085] Step 1: The input signal is isolated by RC filtering and isolation amplifier (ISO124);

[0086] Step 2: After isolation, the signal is converted to digital quantity by a 24-bit ADC (ADS1256);

[0087] Step 3: The FPGA executes the signal conversion logic according to the preset configuration table (see Table 1);

[0088] Step 4: The target signal is output through the DAC (DAC8562) or digital interface.

[0089] Table 1 Signal type configuration table

[0090] Input Type Output Type Configuration Code Response time Applicable Scenarios 4-20mA 0-10V 0x01 0.3s Sensor signal isolation PT100 4-20mA 0x02 0.5s Temperature monitoring system 24V switch RS-485 0x03 0.1s Industrial equipment status feedback

[0091] Example 2:

[0092] The only difference between this embodiment 2 and embodiment 1 is that it is specifically a single-channel current-voltage signal conditioning.

[0093] Application scenario: industrial sensor signal isolation and transmission;

[0094] Hardware configuration:

[0095] Input: 4-20mA current signal (2-wire);

[0096] Output: 0-10V voltage signal;

[0097] Independent transformer parameters: EE25 iron core, 50 turns on the primary side, 100 turns on the secondary side, and withstand voltage 1500VAC.

[0098] Parameter settings:

[0099] Noise feedback PID coefficient: K p =0.5, K i =0.1;

[0100] Load resistance: 250Ω.

[0101] Implementation steps:

[0102] 1. The input signal is connected to the IN+ and IN- terminals of the conditioner;

[0103] 2. Send the configuration command 0x01 through the host computer;

[0104] 3. Adjust the PID parameters to a load regulation rate of <±0.5% (monitor output fluctuations with an oscilloscope);

[0105] 4. Verify the output voltage linearity (error <±0.1%).

[0106] Effect verification: The measured load adjustment rate is ±0.3%, and the crosstalk suppression rate is 62dB.

[0107] Example 3:

[0108] The only difference between this embodiment 3 and embodiment 1 is that it is a dual-channel temperature-current conversion. Application scenario: multi-channel temperature monitoring in process control;

[0109] Hardware configuration:

[0110] Input 1: PT100 (-50℃~200℃);

[0111] Input 2: PT1000 (-100℃~500℃);

[0112] Output: dual channel 4-20mA;

[0113] Independent transformer: double EE20 core, Permalloy shielding layer thickness 0.5mm.

[0114] Parameter settings:

[0115] Noise sampling frequency: 10kHz;

[0116] ADC resolution: 24 bits

[0117] Implementation steps:

[0118] 1. Calibrate PT100 / PT1000 linearization table (segmented fitting, error <0.05℃);

[0119] 2. Configure FPGA mapping relationship (code 0x02);

[0120] 3. When input 1 is applied with a 200°C signal and input 2 is unloaded, the fluctuation of output 2 is <0.05%.

[0121] Effect verification: crosstalk suppression rate 63dB, temperature conversion error ±0.1℃.

[0122] Example 4:

[0123] The only difference between this embodiment 4 and embodiment 1 is that it specifically performs mixed processing of multiple types of signals. Application scenario: smart factory equipment status monitoring.

[0124] Hardware configuration:

[0125] Channel 1: 24V switch → RS-485;

[0126] Channel 2: ±5V voltage → 0-20mA current;

[0127] Channel 3: RTD temperature signal → Modbus RTU protocol.

[0128] Parameter settings:

[0129] Switch debounce time: 10ms;

[0130] Modbus baud rate: 9600bps.

[0131] Implementation steps:

[0132] 1. Configure the signal type of each channel through the GUI software (code 0x03 / 0x04 / 0x05);

[0133] 2. Verify signal switching response time (all <0.5 seconds);

[0134] 3. Long-term operation test (72 hours), communication packet loss rate <0.01%.

[0135] Effect verification: protocol conversion success rate >99.9%, compatible with Siemens S7-1200 PLC.

[0136] Example 5:

[0137] The only difference between this embodiment 5 and embodiment 1 is that it is a low-cost single-channel solution. Application scenario: signal isolation of small devices.

[0138] Hardware configuration:

[0139] Input: 0-5V voltage;

[0140] Output: 4-20mA current;

[0141] Simplified transformer: EE16 core, no magnetic shielding layer.

[0142] Parameter settings:

[0143] Load regulation tolerance range: ±1%;

[0144] Cost optimization: domestic PID chip (such as CH32V103).

[0145] Implementation steps:

[0146] 1. Optimize PCB layout (reduce the number of vias by 30%);

[0147] 2. Bulk purchase of domestic components;

[0148] 3. Full load test (20mA output) temperature rise <15℃.

[0149] Effect verification: The cost of a single channel is reduced to 55 yuan, and the load adjustment rate is ±0.8%.

[0150] Example 6:

[0151] The only difference between this embodiment 6 and embodiment 1 is that it is specifically applied in a high-voltage industrial environment.

[0152] Application scenario: Power system with strong electromagnetic interference environment.

[0153] Hardware configuration:

[0154] Input: 10kV voltage transformer secondary side signal (0-100V AC);

[0155] Output: ±10V isolation voltage;

[0156] Transformer: Withstand voltage 2000VAC, creepage distance 8mm.

[0157] Parameter settings:

[0158] Primary side noise sampling: isolated ADC (AMC1301);

[0159] Feedback loop delay: <2μs.

[0160] Implementation steps:

[0161] 1. Connect a 1MΩ high-voltage resistor in series on the input side (accuracy ±0.1%);

[0162] 2. The output end is connected to a 100MHz bandwidth oscilloscope;

[0163] 3. Apply 1500VAC withstand voltage test for 1 minute, no breakdown.

[0164] Effect verification: Power frequency interference suppression ratio>80dB, in line with IEC 61000-4-4 standard.

[0165] In summary, the measured load regulation of the fully isolated signal conditioner of the present invention is optimized from ±5% of the traditional open-loop power supply to ±0.5%, and the cost is reduced by 35%;

[0166] Moreover, the crosstalk suppression rate between channels is improved to >60dB, and the single / dual / mixed signal channel configuration is flexible;

[0167] Dynamically configure input / output signal types through FPGA or host computer software, supporting mixed processing of current (4-20mA), voltage (0-10V), temperature (PT100), and digital protocols (Modbus). Signal switching time is reduced from 10 minutes in traditional solutions to less than 1 second, making it compatible with mainstream industrial PLC systems.

Claims

1. A fully isolated signal conditioner, characterized in that: It includes a power module, an input module, a programmable signal configuration module and an output module connected to the power module; Isolation modules are provided between the input module and the programmable signal configuration module, between the programmable signal configuration module and the output module, and the power module; The power supply module includes an open-loop power supply and a primary noise feedback module; the open-loop power supply adopts a flyback topology; the primary noise feedback module includes a noise sampling circuit and a digital controller; the primary noise feedback module dynamically adjusts the power supply duty cycle through the feedback algorithm of Formula I; Among them, D adj is the adjusted duty cycle, D base is the reference duty cycle, K p is the proportional coefficient, V noise is the collected primary noise voltage, V ref is the preset reference voltage, K i is the integration coefficient; The isolation module includes at least one independent isolation unit.

2. The fully isolated signal conditioner according to claim 1, wherein: The flyback topology structure includes an input rectifier filter circuit, a flyback transformer, a switch tube, an output rectifier filter circuit, and a drive circuit; The input rectifier and filter circuit converts AC power into DC power, which is then connected to the drain of the switching tube through the primary winding. The source of the switching tube is grounded, and the gate of the switching tube is driven by the PWM signal output by the controller. The drive circuit obtains initial power supply through the starting resistor and continuously supplies power after rectification and filtering by the auxiliary winding of the transformer. The secondary winding of the flyback transformer provides a stable DC voltage to the load through the output rectifier and filter circuit; The switching frequency of the flyback topology is 50 kHz to 200 kHz.

3. The fully isolated signal conditioner according to claim 1, wherein: The noise sampling circuit of the primary side noise feedback module includes a differential amplifier and an isolated analog-to-digital converter; The digital controller calculates the duty cycle compensation amount in real time based on the feedback algorithm and outputs it to the drive circuit via a pulse width modulation signal; The noise sampling circuit obtains the noise signal from the primary sampling resistor of the power module and outputs it to the positive and negative input terminals of the differential amplifier, converting the noise signal into a differential signal input; the differential amplifier filters out low-frequency ripple and high-frequency interference through an internal or external bandpass filter, and then outputs the signal to the analog input channel of the isolated analog-to-digital converter through a programmable gain adjustment module; The digital output end of the isolated analog-to-digital converter is connected to the digital controller.

4. The fully isolated signal conditioner according to any one of claims 1, wherein: The independent isolation unit includes any one or more combinations of transformer isolation, optical coupling isolation, magnetic coupling isolation, and capacitive isolation.

5. The fully isolated signal conditioner according to claim 4, wherein: The transformer isolation includes a transformer and a magnetic shielding structure; The transformer core is encapsulated with Permalloy, with a withstand voltage rating of no less than 1500VAC, and the physical isolation distance between adjacent transformers is greater than 5mm.

6. The fully isolated signal conditioner according to claim 1, wherein: The input signal of the input module includes any one or more combinations of 2 / 3 / 4-wire 4-20mA current, 0-10V / ±5V voltage, PT100 / PT1000 temperature, and 24V DC switch value.

7. The fully isolated signal conditioner according to claim 1, wherein: The output signal of the output module includes any one or more combinations of 0-20mA current, 0-5V / ±10V voltage, and RS-485 / Modbus RTU digital protocol.

8. The fully isolated signal conditioner according to claim 5, wherein: When the independent isolation unit is configured as a single channel, the transformer core is of EE16 size and the number of turns of the primary winding is 40-60.

9. The fully isolated signal conditioner according to claim 5, wherein: When the independent isolation unit is configured with dual channels, the transformer core is of EE20 size, the number of turns of the primary winding is 50-70 turns, and the secondary winding is wound with double-layer shielded wire.

10. The fully isolated signal conditioner according to claim 1, wherein: The programmable signal configuration module includes a multi-channel input interface, a programmable gain amplifier, a switchable filter network, an analog-to-digital converter, a digital control unit and a multi-protocol output interface; After passing through the protection circuit, the input signal enters the programmable gain amplifier for amplitude adjustment, then passes through a digitally controlled filter to filter out noise, and is then converted into a digital signal by an analog-to-digital converter. The digital control unit dynamically configures the signal path and parameters based on a preset algorithm or external instructions, and finally outputs the target signal through the digital-to-analog converter. The signal configuration module switches the signal type through external control instructions, and the switching time is less than 1 second; The configuration logic of the signal configuration module works in conjunction with the primary side noise feedback module to ensure that the load regulation rate of the open-loop power supply module remains less than ±1% during the signal type switching process.

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