Mixed-signal 'scopes gain in-vehicle CAN FD/SENT bus options

April 20, 2015 // By Graham Prophet
Yokogawa has added trigger and analysis options to its DLM2000 (4-channel) and DLM4000 (8-channel) mixed-signal oscilloscopes (MSOs) for testing the latest generation of in-vehicle serial buses.

The new options are specifically designed to address the measurement challenges posed by the CAN FD (CAN with Flexible Data Rate) and SENT (Single Edge Nibble Transmission) bus systems.

CAN FD is a higher-speed version (up to 8 Mbit/sec) of the original CAN Bus designed to provide a faster, more reliable and cost-effective solution to the challenge of the increased amount of data traffic in automotive applications such as firmware updating for ECUs (electronic control units).

SENT is a point-to-point scheme for transmitting signal values from a sensor to a controller. It enables high-resolution and composite data transmission with a lower system cost in applications such as angle sensors for power steering and mass air flow sensors for engine control. SENT can replace existing analogue or PWM signal transmission, and is considered to be cost-effective compared to other serial buses such as CAN/LIN.

When equipped with the new serial bus options, the Yokogawa MSOs will decode the bus signals and display the results in real time. A wide variety of dedicated triggers and search functions is available to aid analysis and troubleshooting on parameters that can affect the bus signals, something that is becoming increasingly important as the amount of traffic across the CAN bus grows with more sophisticated vehicle control systems.

The Yokogawa DLM Series of oscilloscopes are suited to this type of analysis because of the versatility provided by their long memory: in particular, the length of the acquisition memory in Yokogawa's DLM4000 mixed-signal 8-channel oscilloscope is up to 250 Mpoints, making it a straightforward task to handle the extended data frames used in the CAN FD bus that allow the bit rate inside a frame to be changed flexibly. It also makes it possible to display trend data over extended periods: up to 100 seconds of data for SENT signals with microsecond duration, for example.

The DLM2000 is a 4-channel mixed-signal oscilloscope with bandwidths from 200 to