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Application of OWON Tablet Oscilloscope in Volkswagen PASSAT B7 Car Maintenance (1)
- 10/5/2020 -

Use OWON tablet oscilloscope to measure driving CAN waveform

Nowadays, there are more and more control units in automobiles, and the communication of each control unit is generally carried out on the CAN line. CAN line is divided into drive CAN line, often called high-speed CAN, and the other is comfort CAN line, often called low-speed CAN. On the PASSAT B7, both types of CAN cables are in use. LIN line communication is also used between some control units and sensors and actuators. In this application series, we will introduce the test methods one by one. The circuit diagram is very important for waveform analysis. The circuit diagram below is a screenshot of the circuit diagram of the PASSAT B7.

Circuit diagram:

Connect channel 1 and channel 2 of TAO3104A tablet oscilloscope to the CAN line, CH1 to CAN-H, and CH2 to CAN-L. The CAN cable is located at the 68 and 67 terminals of the ECU94 pin plug.



We use the external wiring harness to test, in the figure below, 68 is CAN-H, 67 is CAN-L.


The waveform obtained by using TAO3104A tablet oscilloscope is as follows:




Waveform Features:

● The voltage of CAN-H varies from 2.5V to 3.5V, and the average voltage tested with a multimeter is 2.8V.

● The voltage of CAN-L varies from 2.5V to 1.5V, and the average voltage tested with a multimeter is 2.2V.

● Symmetrical waveform.

● The drive CAN line does not have the ability to operate in a single line.

● When the ignition switch is turned off, the drive CAN will stop "jumping". When the ignition switch is at "ON", it will start to "jump", that is, start to transmit information.

  4-CH TAO3000 Series Tablet Oscilloscope

+ bandwidth up to 120MHz, max real-time sampling rate at 1GSa/s

+ vertical resolution hits 14-bit

+ record length 40M, waveform refreshing rate 75,000 wfms/s

+ low base noise, accurate small-signal capturing

+ miscellaneous triggering/decoding function available

+ SCPI and LabVIEW supported

+ 8’’ 800 x 600 pixels multi-point touch screen

+ multi-CI: USB host, USB device, LAN, and optional Wi-Fi

Tablet oscilloscope

TAO3000 series is equipped with 14-bit high-resolution hardware ADC, the precision is 64 times against other oscilloscope on market. You can observe the waveform details more clearly, and measure the changes of small voltage signals more accurately.

Low background noise allows the oscilloscope to have better small signal measurement capabilities. High storage allows the oscilloscope to acquire longer signals. A high refresh rate allows the oscilloscope to capture waveform details and exceptional events.

TAO3000 series handheld oscilloscopes support multiple trigger modes, including Edge, Video, Pulse, Slope, Runt, Windows, Timeout, I2C, SPI, RS232/UART, CAN, and Nth Edge. Serial bus coding available in I2C, SPI, RS232/UART, and CAN.

Support +, -, *, /, FFT, FFTrms, Intg, Diff, Sqrt, User Defined Function, digital filter (low pass, high pass, bandpass, band reject).

Built-in Wi-Fi module, the user can connect with TAO3000 through a mobile device, realize the same screen display and control, store and view waveform data through the app, share with friends, realize collaborative analysis, and successfully complete the work.

 

2-CH TAO3000 Series Tablet Oscilloscope

2-in-1: DSO + multimeter

Built-in 4½ digits multimeter, the multimeter interface shows on the same screen with the oscilloscope.

The data logging function of the multimeter can record data for a long time, and export to a CSV file.


Multiple operation methods, make the car maintenance test more convenient.

Handheld oscilloscope