A current sensor system

Abstract

The utility model discloses a current sensor system, including current probe, signal optical fiber, control unit and bus analyzer, current probe is connected with control unit through signal optical fiber, control unit is connected with bus analyzer, current probe includes shunt resistance, first photoelectric conversion module, USB charging interface and optical fiber TXD interface, the shunt resistance is connected in series on the power cord of test object, first photoelectric conversion module is connected with shunt resistance, optical fiber TXD interface is connected with first photoelectric conversion module. The utility model discloses, can correct properly to signal wave form to the correct transmission signal and guarantee the interference that can satisfy the limit value requirement of test standard through the current signal after transmission.

Description

Technical Field

[0001] This utility model relates to the field of current sensor technology, specifically a current sensor system. Background Technology

[0002] With technological advancements, electronic components are becoming increasingly prevalent and complex in automobiles. Operating and dormant currents control the operation of various electronic components, and most current testing programs include current control parameters for performance evaluation. Monitoring automotive current signals covers almost all automotive electronic products on the market. In addition to traditional audio, video, antenna tower control signals, and turntable control signals, electromagnetic compatibility testing of the tested products also requires extensive monitoring of current signals.

[0003] According to electromagnetic compatibility (EMC) testing requirements, the product should be in normal operation or sleep mode during testing. When the product under test (DUT) is operating, a current sensor system is essential. If the current signal is passed directly into the system without any processing, the following problems will occur: Insufficient noise reduction processing of the output current signal will result in electromagnetic interference derived from the current signal exceeding background noise requirements. Excessive noise reduction processing of the output current signal will severely degrade the current signal quality, leading to packet loss and communication interruptions at high transmission rates. Utility Model Content

[0004] The purpose of this invention is to provide a current sensor system to solve the problems in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a current sensor system, comprising a current probe, a signal optical fiber, a control unit, and a bus analyzer, wherein the current probe is connected to the control unit via the signal optical fiber, and the control unit is connected to the bus analyzer; The current probe includes a shunt resistor, a first photoelectric conversion module, a USB charging interface, and an optical fiber TXD interface. The shunt resistor is connected in series with the power line of the test object to collect the current signal of the test object. The first photoelectric conversion module is connected to the shunt resistor to convert the current signal collected by the shunt resistor into an optical signal. The optical fiber TXD interface is connected to the first photoelectric conversion module to output the optical signal to the signal optical fiber. The control unit includes an optical fiber RXD interface, a second photoelectric conversion module, an LCD display, a menu rotary switch, a CAN bus interface, a USB data interface, and a trigger output interface. The optical fiber RXD interface is connected to the signal optical fiber for receiving the optical signal. The second photoelectric conversion module is connected to the optical fiber RXD interface for converting the optical signal back into a current signal. The LCD display is connected to the second photoelectric conversion module for displaying the current value corresponding to the current signal and the system menu. The menu rotary switch is connected to the LCD display for adjusting system parameters. The CAN bus interface is connected to the second photoelectric conversion module for outputting the current signal to an external CAN bus. The USB data interface is connected to the second photoelectric conversion module for enabling data interaction between the control unit and external devices and for powering the control unit. The trigger output interface is connected to the second photoelectric conversion module for outputting a TTL trigger signal to an external testing device.

[0006] Preferably, it also includes a battery and a power adapter, wherein the current probe is powered by the battery and the control unit is powered by the battery and the power adapter.

[0007] Preferably, the battery is a lithium-ion battery, and the current measuring head is equipped with a charging status indicator and a working status indicator.

[0008] Preferably, the signal optical fiber is a standard F-SMA cable.

[0009] Compared with the prior art, the beneficial effects of this utility model are: it can correctly transmit signals and appropriately correct the signal waveform, ensuring that the interference caused by the current signal after transmission can meet the limit requirements of the test standard. Attached Figure Description

[0010] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.

[0012] Please see Figure 1 In this embodiment of the present invention, a current sensor system includes a current probe, a signal optical fiber, a control unit, and a bus analyzer. The current probe is connected to the control unit via the signal optical fiber, and the control unit is connected to the bus analyzer. The current probe includes a shunt resistor, a first photoelectric conversion module, a USB charging interface, and an optical fiber TXD interface. The shunt resistor is connected in series with the power line of the test object to collect the current signal of the test object. The first photoelectric conversion module is connected to the shunt resistor to convert the current signal collected by the shunt resistor into an optical signal. The optical fiber TXD interface is connected to the first photoelectric conversion module to output the optical signal to the signal optical fiber. The control unit includes an optical fiber RXD interface, a second photoelectric conversion module, an LCD display, a menu rotary switch, a CAN bus interface, a USB data interface, and a trigger output interface. The optical fiber RXD interface is connected to the signal optical fiber for receiving the optical signal. The second photoelectric conversion module is connected to the optical fiber RXD interface for converting the optical signal back into a current signal. The LCD display is connected to the second photoelectric conversion module for displaying the current value corresponding to the current signal and the system menu. The menu rotary switch is connected to the LCD display for adjusting system parameters. The CAN bus interface is connected to the second photoelectric conversion module for outputting the current signal to an external CAN bus. The USB data interface is connected to the second photoelectric conversion module for enabling data interaction between the control unit and external devices and for powering the control unit. The trigger output interface is connected to the second photoelectric conversion module for outputting a TTL trigger signal to an external testing device.

[0013] The shunt resistor is made of manganese bronze conforming to the DIN 43703 standard. The current measuring head is equipped with different shunt resistors for different rated currents, including shunt resistors adapted to 1A rated current, 10A rated current, and 100A rated current. When the current measuring head is the 1A version, its current resolution is 10μA in normal operating mode and 1μA in moving average mode. When the current measuring head is the 10A version, its current resolution is 100μA in normal operating mode and 10μA in moving average mode. When the current measuring head is the 100A version, its current resolution is 1mA in normal operating mode and 100μA in moving average mode.

[0014] It also includes a battery and a power adapter. The current probe is powered by the battery, and the control unit is powered by both the battery and the power adapter. The battery is a lithium-ion battery, and the current measuring head is equipped with a charging status indicator and a working status indicator. When the USB charging port is connected to an external USB charger or a computer USB port, the lithium-ion battery can be charged. The charging time is approximately 3 hours. The current measuring head is equipped with a charging status indicator and a working status indicator. The charging status indicator is yellow and illuminates during charging, while the working status indicator is green and illuminates during normal operation. When the lithium-ion battery power is too low, the current measuring head automatically shuts down.

[0015] The signal fiber uses a standard F-SMA cable and supports multimode fiber. The specifications of the multimode fiber are 50 / 125μm or 62.5 / 125μm, and the maximum transmission distance of the signal fiber exceeds 200 meters.

[0016] The CAN bus interface includes two 9-pin Sub-D interfaces, one male and one female. These two 9-pin Sub-D interfaces are internally connected, allowing the control unit to be connected in series to an external CAN bus. Pin 2 of the 9-pin Sub-D interface is the CAN-Low signal pin, pin 3 is the CAN_GND signal pin, pin 7 is the CAN_High signal pin, and the remaining pins are unused. The control unit supports both high-speed and low-speed CAN modes. The high-speed CAN mode conforms to the ISO 11898-2 standard, with bus baud rates including 33.3k, 50k, 62.5k, 75k, 83.3k, 100k, 125k, 200k, 250k, 500k, 800k, and 1M. The low-speed CAN mode conforms to the ISO 11898-3 standard, with bus baud rates including 33.3k, 50k, 62.5k, 75k, 83.3k, and 100k. And 125k.

[0017] The control unit stores three calibration factors, which correspond to current measuring heads with rated currents of 1A, 10A, and 100A, respectively.

[0018] The control unit can be connected to an external terminal program via the menu rotary switch or the USB data interface to set trigger modes, including value mode and window mode. In value mode, when the measured current value is less than, equal to, or greater than a set current value, the trigger output interface outputs a high-level TTL trigger signal, and the CAN bus interface outputs a current signal according to a preset output rule. In window mode, a current window range can be set. When the measured current value is within or outside the current window range, the trigger output interface outputs a high-level TTL trigger signal, and the CAN bus interface outputs a current signal according to a preset output rule. The pulse duration of the TTL trigger signal output by the trigger output interface is adjustable, with an adjustment range of 10ms-99.99s.

[0019] The control unit can perform USB-to-CAN conversion via the USB data interface, sending EMC-related data to an external CAN bus. The CAN bus interface outputs current signals in two modes: a permanent output mode and a triggered output mode. In the permanent output mode, the CAN bus interface outputs a current signal 6 times per second. In the triggered output mode, the CAN bus interface outputs a current signal only when a set trigger condition is met. The current signal output by the CAN bus interface is transmitted in 8-byte data format. The first byte is the sign bit, where 0x00 indicates a negative current value and 0x01 indicates a positive current value. Bytes 2-8 are the integer part of the current, in units of 1μA.

[0020] The working principle of this invention is as follows: A high-precision resistor is connected in series with the power line of the test object, the voltage across the resistor is measured, and the current I=U / R is calculated using Ohm's law; the current test signal is converted into an optical signal in a photoelectric conversion module and transmitted over a long distance through optical fiber; at the other end of the optical fiber, it is converted back into a current test signal through another photoelectric conversion module.

[0021] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A current sensor system, characterized in that: It includes a current probe, a signal fiber optic cable, a control unit, and a bus analyzer. The current probe is connected to the control unit via the signal fiber optic cable, and the control unit is connected to the bus analyzer. The current probe includes a shunt resistor, a first photoelectric conversion module, a USB charging interface, and an optical fiber TXD interface. The shunt resistor is connected in series with the power line of the test object, the first photoelectric conversion module is connected to the shunt resistor, and the optical fiber TXD interface is connected to the first photoelectric conversion module. The control unit includes an optical fiber RXD interface, a second photoelectric conversion module, an LCD display screen, a menu rotary switch, a CAN bus interface, a USB data interface, and a trigger output interface. The optical fiber RXD interface is connected to a signal optical fiber, the second photoelectric conversion module is connected to the optical fiber RXD interface, the LCD display screen is connected to the second photoelectric conversion module, the menu rotary switch is connected to the LCD display screen, the CAN bus interface is connected to the second photoelectric conversion module, the USB data interface is connected to the second photoelectric conversion module, and the trigger output interface is connected to the second photoelectric conversion module.

2. The current sensor system according to claim 1, characterized in that: It also includes a battery and a power adapter, with the current probe powered by the battery and the control unit powered by the battery and the power adapter.

3. A current sensor system according to claim 2, characterized in that: The battery is a lithium-ion battery, and the current measuring head is equipped with a charging status indicator and a working status indicator.

4. A current sensor system according to claim 1, characterized in that: The signal fiber uses a standard F-SMA cable.

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