Analog isolation transmitter with zero drift real-time automatic compensation

Abstract

The invention discloses an analog isolation transmitter with zero drift real-time automatic compensation, which comprises a wide power supply input module, a signal per-unit module, a signal amplification module, a signal isolation module, a type matching amplification module, a voltage / current output module and a signal output switching module which are connected in sequence, and also comprises a power supply isolation module, the power supply isolation module carries out power supply isolation on the signal per-unit module, the signal amplification module, the signal isolation module, the type matching amplification module, the voltage / current output module and the signal output switching module. And a zero drift automatic compensation module is arranged between the signal isolation module and the signal output switching module. Aiming at the problems of 1580mm hot rolling basic automatic transmission analog signal type and null drift, real-time automatic compensation of null drift is realized, the anti-interference capability is improved, and the method can be suitable for analog signals of products of the same type.

Description

Technical Field

[0001] The present invention relates to the technology of analog isolation transmitters, and more specifically, to an analog isolation transmitter with real-time automatic zero drift compensation. Background Art

[0002] Currently, the commonly used analog isolation transmitters on the market generally adopt static zero drift adjustment technology, that is, the manufacturer provides a zero drift adjustment potentiometer for the user to zero before use. However, this adjustment method has the following disadvantages:

[0003] 1. There are many factors causing zero drift in analog isolation transmitters, such as noise interference, temperature drift, and component performance changes, and there is a certain degree of randomness. Calibration before commissioning cannot effectively compensate for the zero drift generated during use.

[0004] 2. The commonly used analog isolation transmitters on the market can often only process a single analog signal, while there are a large number of types of analog signals, and various different transmitters are required to process these different signals, which is inconvenient for users and the spare part cost is also high.

[0005] In the existing patent applications, such as Chinese Patent Publication No. CN104932400A discloses a high-precision multi-functional analog signal isolation converter and its conversion method. The converter includes: a wide input power supply module, a multi-functional input module, a processing module, an output module, and an operational amplifier; the wide input power supply module is connected to the multi-functional input module, the processing module, and the output module; among them, the wide input power supply module includes a wide input power supply circuit; the multi-functional input module includes a multi-functional input circuit; the processing module includes a data sampling circuit, a per-unit circuit, and a signal conversion circuit; the output module includes a voltage output circuit and a current output circuit; various internal signals are per-unitized into a unified voltage signal through the per-unit circuit, and voltage output and current output are realized through DIP switches, and the operational amplifier is used for electrical isolation. However, this patented technology does not have the function of automatically compensating zero drift during operation, and cannot overcome the problem of eliminating zero drift during the operation of the device. It is necessary to perform regular off-line calibration to compensate for the zero drift problem, and it is impossible to ensure the online accuracy during the operation of the device in real time, which also brings a huge workload and real-time maintenance difficulties to on-site maintenance. Summary of the Invention

[0006] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide an analog isolation transmitter with real-time automatic zero drift compensation, which realizes real-time automatic zero drift compensation for the analog signal type and zero drift problem of the 1580mm hot rolling basic automation drive, improves the anti-interference ability, and can be applicable to the analog signals of the same type of products.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] An analog isolation transmitter with real-time automatic zero-drift compensation, comprising a wide power input module, a signal per-unitization module, a signal amplification module, a signal isolation module, a type matching amplification module, a voltage / current output module, and a signal output switching module connected in sequence, and further comprising a power supply isolation module and a zero-drift automatic compensation module;

[0009] The power supply isolation module implements power isolation for the signal per-unitization module, the signal amplification module, the signal isolation module, the type matching amplification module, the voltage / current output module, and the signal output switching module;

[0010] A zero-drift automatic compensation module is provided between the signal isolation module and the signal output switching module.

[0011] Preferably, the power supply isolation module includes:

[0012] A bridge rectifier chip U16 for converting the wide power input AV18 - 72V into DC24V;

[0013] DC / DC isolation chips U14, U15 for isolating and converting the DC24V power supply into + / -15V power supply for use in subsequent signal amplification modules, signal isolation modules, type matching amplification modules, and voltage / current output module circuits;

[0014] Power chips U9, U10 for converting the + / -15V power supply into + / -12V power supply for use in subsequent signal amplification modules and signal isolation module circuits;

[0015] Power chips U11, U12 for converting the + / -15V power supply into + / -12V power supply for use in subsequent type matching amplification modules and voltage / current output module circuits;

[0016] A diode D6 for implementing bidirectional overvoltage protection of the input power supply;

[0017] An electronic fuse RU4 for automatically cutting off the power supply when the circuit has a short-circuit overcurrent and automatically restoring power supply when the short-circuit overcurrent of the circuit is restored.

[0018] Preferably, the zero-drift automatic compensation module includes:

[0019] An amplifier chip U3 connected to the signal output switching module;

[0020] A resistor R24_00 connected to the amplifier chip U3;

[0021] A variable potentiometer VR1 connected to the amplifier chip U3.

[0022] Preferably, the signal per-unit module includes input terminals X1, X2, X3, X4, an electronic fuse RU1, sampling resistors R1A / B, R2A / B, R3A / B, R4A / B, R5A / B, R6A / B, and DIP switches S1, S2;

[0023] When the input signals of the input terminals X3 and X4 are voltage signals and there is a short circuit and overcurrent, the electronic fuse RU1 automatically cuts off the circuit, and when the short circuit is restored, the electronic fuse RU1 automatically resumes its function;

[0024] The sampling resistors R1A / B, R2A / B, R3A / B, R4A / B, R5A / B, R6A / B are used to achieve signal voltage division;

[0025] When the input signals of the input terminals X1, X2, X3, X4 are current signals, connect to the input terminal X1 or X2 according to the signal range and select the corresponding DIP switch S2;

[0026] When the DIP switch S1 is selected, the input voltage signal of 5V is converted into a 0.1V standard signal through the per-unit conversion circuit and input to the subsequent signal amplification module circuit for further processing.

[0027] Preferably, the signal isolation module includes:

[0028] An amplifier chip U1, used to amplify the input 0.1V per-unit signal to 2.5V;

[0029] A voltage detection isolation amplifier ISO124U, used to completely isolate the analog input from the internal conversion circuit and output circuit of the converter.

[0030] Preferably, the voltage / current output module includes amplifier chips U6, DIP switch S4, resistors R14, R15, R16, R17, R18, amplifier chip U8, triode Q1, amplifier chip U7, and resistor R21A - B;

[0031] The amplifier chip U6, the DIP switch S4, and the resistors R14, R15, R16, R17, R18 are used to achieve inverse per-unit;

[0032] The amplifier chip U8, the triode Q1, the amplifier chip U7, and the resistor R21A - B are used to achieve voltage - current conversion output.

[0033] The analog isolation transmitter with real-time automatic compensation for zero drift provided by the present invention has solved the technical difficulties of analog signal zero drift and transmission under complex working conditions through its application practice on the 1580 hot rolling production line of Baosteel Co., Ltd.; and can be applied to complex working conditions by selecting the analog signal type through a jumper and performing corresponding conversion and transmission. The present invention has the function of automatic compensation for zero drift, which completely overcomes the difficulty of eliminating zero drift during the operation of the equipment. It does not need to compensate for the zero drift problem through regular offline calibration, and can ensure the online accuracy of the equipment in real time during operation, greatly reducing the workload of on-site maintenance and the difficulty of real-time maintenance. This technology is suitable for promotion and application in similar systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the framework structure of the analog isolation transmitter of the present invention;

[0035] Figure 2 It is a circuit diagram of a power supply isolation module in the analog isolation transmitter of the present invention;

[0036] Figure 3 It is a circuit diagram of a signal normalization module in the analog isolation transmitter of the present invention;

[0037] Figure 4 It is a circuit diagram of a signal isolation module in the analog isolation transmitter of the present invention;

[0038] Figure 5 It is a circuit diagram of a voltage / current output module in the analog isolation transmitter of the present invention;

[0039] Figure 6 The invention discloses a circuit diagram of a zero drift automatic compensation module in an analog isolation transmitter. DETAILED DESCRIPTION

[0040] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0041] Combination Figure 1 As shown, an analog isolation transmitter with real-time automatic compensation for zero drift provided by the present invention includes a wide power input module 1, a signal standardization module 2, a signal amplification module 3, a signal isolation module 4, a type matching amplification module 5, a voltage / current output module 6 and a signal output switching module 7 which are connected in sequence, and also includes a power supply isolation module 8.

[0042] Existing control systems often consist of multiple sensors and multiple power supplies. Conventional circuit designs use the same power supply, which can easily cause interference between multiple sensors and between the sensors and the ground.

[0043] The power supply isolation module 8 of the present invention is used to implement power isolation for the signal per-unit module 2, signal amplification module 3, signal isolation module 4, type matching amplification module 5, voltage / current output module 6, and signal output switching module 7, avoiding interference between them from the electrical design, and at the same time meeting the wide power input range of AC18 - 72V, which has a wider applicable range than the conventional single DC24V power input requirement.

[0044] Meanwhile, the present invention also has a zero drift automatic compensation module 9 between the signal isolation module 4 and the signal output switching module 7.

[0045] Combined Figure 2 As shown, the power supply isolation module 8 includes:

[0046] A bridge rectifier chip U16, used to convert the wide power input AV18 - 72V into DC24V;

[0047] DC / DC isolation chips U14, U15, used to isolate and convert the DC24V power supply into + / -15V power supply for the subsequent signal amplification module, signal isolation module, type matching amplification module, and voltage / current output module circuits to use;

[0048] Power chips U9, U10, used to convert the + / -15V power supply into + / -12V power supply for the subsequent signal amplification module and signal isolation module circuits to use;

[0049] Power chips U11, U12, used to convert the + / -15V power supply into + / -12V power supply for the subsequent type matching amplification module and voltage / current output module circuits to use;

[0050] A diode D6, used to achieve bidirectional overvoltage protection of the input power supply;

[0051] An electronic fuse RU4, used to automatically cut off the power supply when the circuit has a short - circuit over - current, and can automatically resume power supply when the short - circuit over - current of the circuit is restored.

[0052] Among them, U14 / U15 uses a DC / DC isolation chip PWA4815, U10 / U12 uses a 78L12 power chip, U9 / U11 uses a 79L12 power chip, and C20 - C23 are power filter capacitors, used to improve the power quality.

[0053] Combined Figure 3 As shown, the present invention uses jumpers to implement the input of various analog signal types, and can achieve the input of current + / -20mA, current + / -10mA, voltage + / -20V, voltage + / -10V, voltage + / -5V, voltage + / -2V, voltage + / -0.1V.

[0054] The wide power supply input module 1 mainly converts current into voltage, normalizes the voltage signal into a low-level 0.1V signal, and supplies it for further processing by the subsequent circuit.

[0055] The signal normalization module 2 includes input terminals X1, X2, X3, X4, electronic fuse RU1, sampling resistors R1A / B, R2A / B, R3A / B, R4A / B, R5A / B, R6A / B, and DIP switches S1, S2;

[0056] When the input signals of input terminals X3 and X4 are voltage signals and there is a short circuit and overcurrent, the electronic fuse RU1 automatically cuts off the circuit, and when the short circuit is restored, the electronic fuse RU1 automatically resumes its function;

[0057] The sampling resistors R1A / B, R2A / B, R3A / B, R4A / B, R5A / B, R6A / B are used to achieve signal voltage division;

[0058] When the input signals of input terminals X1, X2, X3, and X4 are current signals, select to connect to input terminal X1 or X2 according to the signal range and select the corresponding DIP switch S2;

[0059] Example of input resistance matching calculation (5V voltage type input):

[0060]

[0061] When the DIP switch S1 is selected, the input 5V voltage signal is converted into a 0.1V standard signal through the normalization circuit and input to the subsequent signal amplification module and signal isolation module circuits for further processing.

[0062] Combined with Figure 4 As shown, the present invention adopts an input isolation design to improve the input noise suppression and anti-interference ability. The signal isolation module 4 includes:

[0063] Amplifier chip U1, used to amplify the input 0.1V normalized signal to 2.5V;

[0064] Voltage detection isolation amplifier ISO124U, used to completely isolate the analog input from the internal conversion circuit and output circuit of the converter, so as to improve the anti-interference ability.

[0065] Among them, U1 adopts the AD8220 high-precision amplifier chip, and ISO124U adopts a precision voltage detection isolation amplifier.

[0066] Any type of input signal is processed at the same level internally. The per-unit 0.1V standard signal is amplified by a high-precision amplifier circuit into a 2.5V signal, which is achieved by the amplifier chip U1. VR3 is the offset potentiometer, and electrical isolation is achieved by the voltage detection isolation amplifier ISO124U.

[0067] Combined with Figure 5 As shown, the present invention uses jumpers to achieve the output of different types of current and voltage signals. Through input and output jumpers, the conversion output of almost all analog signals can be basically achieved, enabling a processor to be applicable to almost all analog signal processing application scenarios. The voltage / current output module includes the amplifier chip U6, DIP switch S4, resistors R14, R15, R16, R17, R18, amplifier chip U8, triode Q1, amplifier chip U7, and resistor R21A - B;

[0068] The amplifier chip U6, DIP switch S4, and resistors R14, R15, R16, R17, R18 are used to achieve inverse per-unit conversion;

[0069] The amplifier chip U8, triode Q1, amplifier chip U7, and resistor R21A - B are used to achieve voltage - current conversion output.

[0070] Among them, the amplifier chip U6 uses the OP27 amplifier, the amplifier chip U8 uses the AD82777 high - precision amplifier, the amplifier chip U7 uses the AD822 amplifier, and the triode Q1 uses the 2N3904 triode.

[0071] Combined with Figure 6 As shown, the present invention adopts the design idea of introducing large output zero - drift feedback. The zero - drift randomly generated by noise interference, temperature drift, component performance changes, etc. of the analog transmitter is sampled and fed back to the input circuit for overall automatic compensation, greatly improving the anti - interference ability and conversion accuracy. The zero - drift automatic compensation module 9 includes:

[0072] The amplifier chip U3, connected to the signal output switching module;

[0073] The resistor R24_00, connected to the amplifier chip U3;

[0074] The adjustable potentiometer VR1, connected to the amplifier chip U3.

[0075] The direction of the compensation signal is as shown by the arrow direction in Figure 6 the arrow direction shown in

[0076] Among them, the amplifier chip U3 uses the AD8277 high - precision amplifier.

[0077] The analog isolation transmitter of the present invention adopts power supply isolation, input circuit level matching and signal isolation, per-unitized level conversion design, designs a hardware for automatic zero drift compensation, and at the same time designs input and output circuits with strong anti-interference ability. It realizes real-time automatic compensation of zero drift, improves the anti-interference ability, and can be applied to almost all analog signals.

[0078] Those of ordinary skill in the art in this technical field should recognize that the above embodiments are only used to illustrate the present invention, rather than to limit the present invention. As long as within the scope of the essential spirit of the present invention, changes and modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. An analog isolation transmitter with real-time automatic zero-drift compensation, comprising a wide power input module, a signal per-unitization module, a signal amplification module, a signal isolation module, a type matching amplification module, a voltage / current output module, and a signal output switching module connected in sequence, characterized in that: It also includes a power supply isolation module; The power supply isolation module isolates the power supply for the signal per-unit module, the signal amplification module, the signal isolation module, the type matching amplification module, the voltage / current output module, and the signal output switching module; A zero-drift automatic compensation module is provided between the signal isolation module and the signal output switching module.

2. The analog isolation transmitter with zero-drift real-time automatic compensation according to claim 1, characterized in that, The power supply isolation module includes: A bridge rectifier chip U16 for converting the wide power supply input AV18 - 72V into DC24V; DC / DC isolation chips U14 and U15 for isolating and converting the DC24V power supply into + / -15V power supply for subsequent signal amplification module, signal isolation module, type matching amplification module, and voltage / current output module circuits; Power chips U9 and U10 for converting the + / -15V power supply into + / -12V power supply for subsequent signal amplification module and signal isolation module circuits; Power chips U11 and U12 for converting the + / -15V power supply into + / -12V power supply for subsequent type matching amplification module and voltage / current output module circuits; A diode D6 for realizing two-way overvoltage protection of the input power supply; An electronic fuse RU4 for automatically cutting off the power supply when the circuit has a short circuit overcurrent and automatically restoring the power supply when the short circuit overcurrent of the circuit is restored.

3. The analog isolation transmitter with zero-drift real-time automatic compensation according to claim 1, characterized in that The zero-drift automatic compensation module includes: An amplifier chip U3 connected to the signal output switching module; A resistor R24_00 connected to the amplifier chip U3; An adjustable potentiometer VR1 connected to the amplifier chip U3.

4. The analog isolation transmitter with real-time automatic zero-drift compensation according to claim 1, characterized in that: The signal per-unit module includes input connection terminals X1, X2, X3, X4, an electronic fuse RU1, sampling resistors R1A / B, R2A / B, R3A / B, R4A / B, R5A / B, R6A / B, and DIP switches S1, S2; When the input signals of the input connection terminals X3 and X4 are voltage signals and there is a short circuit overcurrent, the electronic fuse RU1 automatically cuts off the circuit, and when the short circuit is restored, the electronic fuse RU1 automatically restores its function; The sampling resistors R1A / B, R2A / B, R3A / B, R4A / B, R5A / B, R6A / B are used to realize signal voltage division; When the input signals of the input connection terminals X1, X2, X3, X4 are current signals, connect to the input connection terminal X1 or X2 according to the signal range and select the corresponding DIP switch S2; When the DIP switch S1 is selected, the input voltage signal of 5V is converted into a 0.1V standard signal through the per-unit conversion circuit and input to the subsequent signal amplification module and signal isolation module circuits for further processing.

5. The analog isolation transmitter with real-time automatic zero-drift compensation according to claim 1, characterized in that The signal isolation module includes: An amplifier chip U1 for amplifying the input 0.1V per-unit signal to 2.5V; A voltage detection isolation amplifier ISO124U for completely isolating the analog input from the internal conversion circuit and output circuit of the converter.

6. The analog isolation transmitter with zero-drift real-time automatic compensation according to claim 1, wherein The voltage / current output module includes amplifier chip U6, DIP switch S4, resistors R14, R15, R16, R17, R18, amplifier chip U8, triode Q1, amplifier chip U7, and resistor R21A-B; The amplifier chip U6, the DIP switch S4, and the resistors R14, R15, R16, R17, R18 are used to achieve inverse per-unitization; The amplifier chip U8, the triode Q1, the amplifier chip U7, and the resistor R21A-B are used to achieve voltage-current conversion output.

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