Analyzing CAN/LIN signals at protocol layer with the R&S RTM universal oscilloscope from Rohde & Schwarz

March 07, 2012 // By Christoph Hammerschmidt
Users have always been able to verify the quality of CAN/LIN signals with the R&S RTM by measuring characteristics such as amplitude and rise time. Thanks to the new R&S RTM-K3 triggering and decoding option, users can now view signals at the protocol layer and quickly and easily analyze the content of transmitted messages.

Controller area network (CAN) and local interconnect network (LIN) are serial communications buses. They are mainly used in the automotive industry to interconnect control devices or sensors. When electrical components with a CAN/LIN interface are put into operation, any faults and their origins need to be quickly and reliably found. The R&S RTM-K3 option is an invaluable troubleshooting tool, because it triggers on CAN/LIN-specific protocol data and decodes the recorded waveforms into easy-to-read protocol content.

As with the I2C/SPI and UART/RS-232 options, the hardware-based decoding is done in realtime. The resulting high acquisition rate allows the oscilloscope to quickly find faults. Equipped with the new option, the R&S RTM provides even more flexibility with a wide variety of protocol-specific triggers such as for triggering on protocol errors or on specific content (e.g. to filter specific individual messages out of the transmitted data).

It goes without saying that the new option is intuitive to use, like all Rohde & Schwarz oscilloscope applications. Simple test dialogs with explanatory graphics make configuration easy. To present measurement results in a clear-cut and straightforward manner, protocol details in the measured waveform are color-coded and protocol data is compiled in tables. The zoom function allows the user to quickly view relevant data in detail. When the zoom factor is increased, more information about the relevant part of the message is displayed. To further improve readability of the decoded data, a user-defined name for the component (e.g. 'brake' or ‘windshield wiper’) can be displayed instead of the hexadecimal address.