Double-probe non-contact CAN signal measuring device and measuring method thereof

Abstract

The invention discloses a double-probe non-contact CAN signal measuring device and a measuring method thereof, and belongs to the technical field of vehicle electric control system testing. The signal processing module is in signal transmission connection with the display module, the mode switching module and the amplification factor adjusting knob, and the signal processing module, the display module, the mode switching module and the amplification factor adjusting knob are electrically connected with the power supply control module; the signal processing module is connected with the two metal probes through the wire harness, and the outer side of each metal probe is provided with a measuring clamp. According to the invention, a non-contact probe structure is adopted to realize independent shunt acquisition of multipath CAN signals, parallel access of multiple devices such as a calibration tool and a data acquisition instrument can be supported without arranging a reserved joint in advance, wire harness insulation damage and short circuit risks caused by a physical contact interface are avoided, the safety of a vehicle electric control system is guaranteed, time consumed for on-site modification is reduced, and the cost is reduced. And the bus signal integrity is ensured.

Description

Technical Field

[0001] The invention relates to a double-probe non-contact CAN signal measuring device and a measuring method thereof, belonging to the technical field of vehicle electronic control system testing. Background Art

[0002] During the vehicle R&D and test verification phase, multi-dimensional testing requirements include calibration testing, high-altitude / high-temperature / high-cold (three highs) environmental adaptability testing, fault diagnosis, and competitive product benchmarking analysis. Existing technologies typically rely on the on-board diagnostic interface (OBD) or a reserved dedicated test connector for CAN bus signal access. When it is necessary to simultaneously connect multiple types of test equipment, such as calibration tools, data acquisition instruments, fault injection devices, and cloud-based diagnostic platforms, existing solutions have the following technical drawbacks: 1. Channel resource limitations: A single OBD interface cannot implement the shunting and collection of multiple CAN signals, making it difficult to meet the signal collection requirements of multiple devices connected in parallel. The reserved test connector requires the pre-layout of a dedicated wiring harness during the vehicle design phase, significantly reducing the flexibility of the test solution. 2. Risks of contact measurement: The physical contact interface achieved through wiring harness modification can easily damage the original insulation layer, significantly increasing the probability of short-circuit failures and posing a potential threat to the safety of the vehicle's electronic control system. 3. Adaptability defects: On-site modification of the test interface requires a lot of debugging time, seriously delaying the R&D process; in benchmarking tests of competing vehicles, the broken-line interface modification may lead to incomplete collection of key bus data, affecting the validity of the test results. Summary of the Invention

[0003] In order to solve the problems existing in the background technology, the present invention provides a dual-probe non-contact CAN signal measurement device and a measurement method thereof.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solutions: a dual-probe non-contact CAN signal measuring device, comprising a metal probe, a signal processing module, a display module, a power control module, a mode switching module, a magnification adjustment knob and a measuring clamp; the signal processing module is installed in an outer shell, and the outer shell is equipped with a display module, a power control module, a mode switching module and a magnification adjustment knob; the signal processing module is connected to the display module, the mode switching module and the magnification adjustment knob for signal transmission, and the signal processing module, the display module, the mode switching module and the magnification adjustment knob are all electrically connected to the power control module; the signal processing module is connected to the two metal probes through a wiring harness, and a measuring clamp is installed on the outside of each metal probe.

[0005] Further, the signal processing module comprises, in sequence, an ultrahigh-impedance buffer, a preamplifier, an adjustable gain amplifier, and a microprocessor, the ultrahigh-impedance buffer being connected with the two metal probes; the adjustable gain amplifier is connected with an amplification multiple adjusting knob through a circuit; the microprocessor is connected with a display module, a mode switching module, and the amplification multiple adjusting knob through a circuit for signal transmission, respectively, and an output interface of the microprocessor is connected with a rear-end detection device through a wire harness.

[0006] The application further provides a measurement method of the double-probe non-contact CAN signal measurement device. S1: split the twisted pair of the CAN bus to be measured, and tightly wind the split CAN_H line and the CAN_L line along the roots of the corresponding metal probes, respectively, and then clamp the CAN_H line and the CAN_L line through the clamping jaws of the corresponding measurement clamps, respectively; S2: the CAN_H line and the CAN_L line form independent primary coils with the corresponding wound metal probes, respectively, and the high-speed changing differential pulses transmitted in the primary coils generate an alternating magnetic field; S3: based on the Faraday's law of electromagnetic induction, the alternating magnetic field generated by the primary coils induces an induced voltage consistent with the original signal change law on the metal probes as secondary coils, thereby realizing non-contact signal pickup; S4: reduce the attenuation of the induced voltage signal through an ultrahigh-impedance buffer; S5: preliminarily amplify through a preamplifier; S6: control the adjustable gain amplifier to dynamically scale the induced voltage signal to a stable standard range through an amplification multiple adjusting knob; S7: transmit the amplified induced voltage signal to a microprocessor, the microprocessor converts the signal into a value corresponding to the actual differential voltage of the CAN bus in real time, and displays the value directly through a display module; at the same time, the maximum value or the minimum value is selected and displayed through a mode switching function; S8: transmit the processed induced voltage signal to a rear-end detection device through the microprocessor, thereby realizing parallel collection and analysis of the CAN signal.

[0007] Further, the winding directions and the winding numbers of the CAN_H line and the CAN_L line in S1 are the same.

[0008] Compared with the prior art, the application has the following beneficial effects: The application adopts a non-contact probe structure to realize independent shunt collection of multiple CAN signals, breaks through the channel resource limitation of a single OBD interface, supports parallel access of multiple devices such as a calibration tool and a data collection instrument without needing to arrange a reserved joint in advance, directly picks up the CAN bus alternating magnetic field signal based on the Faraday's law of electromagnetic induction, avoids the insulation damage and short circuit risk of a physical contact type interface, guarantees the safety of the vehicle electronic control system, realizes fast operation mode of winding and measuring, greatly reduces the time consumption of on-site modification, eliminates the data missing problem caused by the modification of a broken interface in the competitive product to the standard test, ensures the integrity of the bus signal, realizes accurate conversion and intuitive monitoring of the differential voltage through high-impedance buffering to suppress signal attenuation, adjustable gain amplification to dynamically scale and mode switching display (maximum value / minimum value), meets the signal adaptation requirements of multiple types of test equipment, and significantly improves the development efficiency and test safety of a sample vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a structural schematic diagram of the application; Figure 2 is a structural block diagram of the application. DETAILED DESCRIPTION

[0010] The technical solutions in the application will be described clearly and completely below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the application.

[0011] A double-probe non-contact CAN signal measurement device, comprising a metal probe 1, a signal processing module 2, a display module 3, a power control module 4, a mode switching module 5, an amplification multiple adjusting knob 6 and a measurement clamp 7; the signal processing module 2 is installed in an outer shell, the outer shell is provided with the display module 3, the power control module 4, the mode switching module 5 and the amplification multiple adjusting knob 6, the signal processing module 2 is in signal transmission connection with the display module 3, the mode switching module 5 and the amplification multiple adjusting knob 6, and the signal processing module 2, the display module 3, the mode switching module 5 and the amplification multiple adjusting knob 6 are in electrical connection with the power control module 4; the signal processing module 2 is connected with the two metal probes 1 through a wire harness, and the measurement clamp 7 is installed on the outer side of each metal probe 1.

[0012] The power control module 4 is a power switch; the display module 3 is an electronic display screen. The measurement clamp 7 is a left-right opening and closing and closed clamp, which is a prior art and can be obtained by outsourcing, so it will not be described in detail.

[0013] Further, the signal processing module 2 comprises, in sequence, an ultrahigh-impedance buffer, a preamplifier, an adjustable gain amplifier, and a microprocessor, the ultrahigh-impedance buffer being connected with the two metal probes 1; the adjustable gain amplifier is connected with the amplification multiple adjusting knob 6 through a circuit; the microprocessor is connected with the display module 3, the mode switching module 5, and the amplification multiple adjusting knob 6 through a circuit, respectively, for signal transmission, and the output interface of the microprocessor is connected with a rear-end detection device (such as a calibration tool, a data acquisition instrument, etc.) through a wire harness.

[0014] The application further provides a measurement method of the double-probe non-contact CAN signal measurement device. S1: The twisted pair of the CAN bus to be measured is split, and the split CAN_H line and CAN_L line are tightly wound around the corresponding metal probe 1 at the root of the corresponding metal probe 1, and then clamped by the clamping jaws of the corresponding measurement clamp 7, so as to be tightly fixed with the corresponding metal probe 1, thereby forming a stable electromagnetic coupling structure; S2: The CAN_H line and the CAN_L line and the corresponding wound metal probe 1 form independent primary coils as original coils, and the high-speed changing differential pulses transmitted in the original coils will generate an alternating magnetic field, which is a signal source of electromagnetic induction; S3: The metal probe 1 is made of conductive material, and in the alternating magnetic field generated by the primary coil CAN line, it is equivalent to a secondary coil in electromagnetic induction. Based on the Faraday's law of electromagnetic induction, the alternating magnetic field generated by the primary coil will induce an induced voltage on the metal probe 1 as a secondary coil, which is consistent with the change rule of the original signal, thereby realizing non-contact signal pickup; the induced voltage signal on the metal probe 1 is weak and easy to be disturbed, and therefore needs to be processed by the signal processing module 2.

[0015] S4: The ultrahigh-impedance buffer is used to reduce the attenuation of the induced voltage signal and avoid the influence of the load on the induced voltage signal; S5: The preamplifier is used for preliminary amplification to suppress noise interference; S6: The amplification multiple adjusting knob 6 is used to control the adjustable gain amplifier to dynamically scale the induced voltage signal to a stable range of the display, the standard range of the high-speed CAN is based on the ISO11898-2 standard, and the standard range of the low-speed CAN is based on the ISO11898-3 standard, so that the intensity of the induced voltage signal is adapted to the subsequent processing requirements; S7: The amplified induced voltage signal is transmitted to the microprocessor, the microprocessor converts it into a value corresponding to the actual differential voltage of the CAN bus in real time, and displays it directly through the display module 3; at the same time, the maximum value or the minimum value is selected through the mode switching function, so as to facilitate the observation of the signal characteristics; S8: The processed inductive voltage signal is transmitted to a back-end detection device through a microprocessor to realize parallel collection and analysis of the CAN signal.

[0016] Further, the winding directions and the number of winding turns of the CAN_H line and the CAN_L line in S1 are the same.

[0017] It is apparent for a person skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but can be implemented in other forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered as exemplary and not limiting, the scope of the present application being defined by the appended claims rather than the above description, and all changes falling within the meaning and range of equivalency of the claims are intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the claims concerned.

[0018] Furthermore, it should be understood that although the present specification describes exemplary embodiments, not every exemplary embodiment contains only one independent technical solution, and the present specification is described in this way only for the sake of clarity, and a person skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by a person skilled in the art.

Claims

1. A dual-probe non-contact CAN signal measurement device, characterized by: The invention comprises a metal probe (1), a signal processing module (2), a display module (3), a power control module (4), a mode switching module (5), an amplification adjustment knob (6) and a measuring clamp (7); the signal processing module (2) is installed in an outer shell, the outer shell is equipped with a display module (3), a power control module (4), a mode switching module (5) and an amplification adjustment knob (6); the signal processing module (2) and the display module (3), the mode switching module (5) and the amplification adjustment knob (6) are all connected for signal transmission; the signal processing module (2), the display module (3), the mode switching module (5) and the amplification adjustment knob (6) are all electrically connected to the power control module (4); the signal processing module (2) is connected to the two metal probes (1) through a wiring harness, and a measuring clamp (7) is installed on the outer side of each metal probe (1).

2. The dual-probe non-contact CAN signal measuring device according to claim 1, characterized in that: The signal processing module (2) comprises an ultra-high impedance buffer, a preamplifier, an adjustable gain amplifier and a microprocessor connected in sequence, wherein the ultra-high impedance buffer is connected to two metal probes (1); the adjustable gain amplifier is connected to the amplification factor adjustment knob (6) via a line; the microprocessor is connected to the display module (3), the mode switching module (5) and the amplification factor adjustment knob (6) for signal transmission via lines, and the output interface of the microprocessor is connected to the back-end detection equipment via a wiring harness.

3. A measurement method according to the dual-probe non-contact CAN signal measurement device of claim 1 or 2, characterized in that: The method comprises the following steps: S1: Split the twisted pair of the CAN bus to be tested, and tightly wind the CAN_H line and CAN_L line obtained by splitting around the corresponding metal probe (1) along the root of the corresponding metal probe (1), and then clamp them respectively through the clamping claws of the corresponding measuring clamp (7); S2: The CAN_H line and the CAN_L line and the corresponding wound metal probe (1) form independent primary coils, and the high-speed differential pulses transmitted inside them will generate an alternating magnetic field; S3: Based on Faraday's law of electromagnetic induction, the alternating magnetic field generated by the primary coil will induce an induced voltage on the metal probe (1) as the secondary coil that is consistent with the change law of the original signal, thus realizing non-contact signal pickup; S4: Reduce the attenuation of the induced voltage signal through an ultra-high impedance buffer; S5: Preliminary amplification by preamplifier; S6: Control the adjustable gain amplifier through the amplification adjustment knob (6) to dynamically scale the induced voltage signal until the reading is stable within the standard range; S7: The induced voltage signal after amplification is transmitted to the microprocessor, which converts it into a numerical value corresponding to the actual differential voltage of the CAN bus in real time and displays it visually through the display module (3); at the same time, the maximum value or minimum value is selected for display through the mode switching function; S8: The processed induced voltage signal is transmitted to the back-end detection equipment through the microprocessor to realize the parallel collection and analysis of the CAN signal.

4. The method according to claim 3, wherein: The winding direction and number of winding turns of the CAN_H line and the CAN_L line described in S1 are the same.

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