How to detect the quality of CAN communication circuit

CAN (Controller Area Network) is a local area network technology based on bus communication, which is widely used in automotive electronics, industrial control and other fields. In practical applications, the quality of CAN communication circuit has an important impact on the stability and reliability of the entire system. This article will introduce in detail how to detect the quality of CAN communication circuit, including detection methods, detection tools, detection process and common problem handling.

1. Detection method

1. Visual inspection

Before testing the CAN communication circuit, you must first conduct a visual inspection to check whether the circuit board is burned, damaged, corroded, etc., check whether the connector is loose or damaged, and check whether the cable is broken or worn.

1. Resistance detection

Use a multimeter to measure the resistance value in the CAN communication circuit, including bus resistance, terminal resistance, etc. Under normal circumstances, the resistance value of the CAN bus should be between 60-120Ω, and the terminal resistance value should be around 120Ω.

1. Voltage detection

Use a multimeter to measure the voltage value in the CAN communication circuit, including power supply voltage, signal voltage, etc. Under normal circumstances, the power supply voltage of the CAN bus should be between 9-30V, and the signal voltage should be between 0-5V.

1. Signal integrity testing

Use an oscilloscope or logic analyzer to detect the signal integrity in the CAN communication circuit, including the signal rise time, fall time, amplitude, waveform, etc. Under normal circumstances, the rise time of the CAN signal should be between 1-3μs, the fall time should be between 1-2μs, and the amplitude should be between 0.9-2.5V.

1. Communication test

Use CAN communication test tools, such as CAN card, CAN analyzer, etc. to perform communication test. The test content includes communication rate, communication distance, communication quality, etc.

2. Testing tools

1. multimeter

A multimeter is a commonly used electronic measuring tool that can measure parameters such as resistance, voltage, and current. In the detection of CAN communication circuits, the multimeter is mainly used to measure resistance and voltage.

1. Oscilloscope

An oscilloscope is an instrument used to observe and measure the waveform of electrical signals. In the detection of CAN communication circuits, the oscilloscope is mainly used to observe the waveform, amplitude, time and other parameters of the signal.

1. Logic Analyzer

A logic analyzer is an instrument used to measure and analyze digital signals. In the detection of CAN communication circuits, the logic analyzer is mainly used to measure signal parameters such as timing and frequency.

1. CAN Card

CAN card is a hardware device used to implement CAN communication, which can be inserted into the PCI slot or USB interface of the computer. In the detection of CAN communication circuit, CAN card is mainly used for communication test.

1. CAN Analyzer

CAN analyzer is a professional CAN communication test tool that can monitor and analyze the communication data on the CAN bus in real time. In the detection of CAN communication circuits, CAN analyzer is mainly used for signal integrity detection and communication testing.

3. Testing Process

1. Preparation

Before testing the CAN communication circuit, you need to prepare the corresponding testing tools, such as multimeter, oscilloscope, logic analyzer, CAN card, etc. At the same time, you also need to be familiar with the basic principles and parameter requirements of the CAN communication circuit.

1. Visual inspection

Perform a visual inspection of the CAN communication circuit as described above to check if the circuit board, connectors, cables, etc. are damaged or abnormal.

1. Resistance detection

Use a multimeter to measure the resistance value in the CAN communication circuit, including bus resistance, terminal resistance, etc. If the resistance value is not within the normal range, you need to further check whether there are problems with the circuit board, connector, cable, etc.

1. Voltage detection

Use a multimeter to measure the voltage value in the CAN communication circuit, including power supply voltage, signal voltage, etc. If the voltage value is not within the normal range, you need to check whether there are problems with the power supply, circuit board, etc.

1. Signal integrity testing

Use an oscilloscope or logic analyzer to detect the signal integrity in the CAN communication circuit, including the signal rise time, fall time, amplitude, waveform, etc. If the signal parameters are not within the normal range, you need to check whether there are problems with the circuit board, connector, cable, etc.

1. Communication test

Use a CAN card or CAN analyzer to perform communication tests, including communication rate, communication distance, communication quality, etc. If the communication test results are not ideal, further analysis of the causes is required and adjustments should be made.

1. Problem Solving

According to the test results, analyze the problems in the CAN communication circuit and take corresponding measures to deal with them. Common problems include abnormal resistance, abnormal voltage, signal integrity problems, communication failures, etc.

4. Common Problem Solving

1. Abnormal resistance

If the resistance value is not within the normal range, it may be caused by circuit board damage, poor connector contact, cable breakage, etc. You need to replace the damaged parts or reconnect the connector or cable.

1. Abnormal voltage

If the voltage value is not within the normal range, it may be caused by unstable power supply, circuit board damage, etc. It is necessary to check the power supply, circuit board and other components, and make corresponding adjustments or replacements.

1. Signal integrity issues

If the signal's rise time, fall time, amplitude, waveform and other parameters are not within the normal range, it may be caused by unreasonable circuit board design, poor connector contact, cable quality problems, etc. It is necessary to optimize the circuit board design, replace the connector or cable.