Automotive SENT sensor testing

application

As a new type of digital serial interface technology, SENT (Single Edge Nibble Transmission) sensor has been widely used in the automotive manufacturing industry. It is used in engine management systems, airbags, brake systems, steering systems, transmission systems, chassis control systems and other fields, effectively improving the performance and safety of automobiles.

Customer needs

On the automotive production line, it is particularly important to accurately test the SENT sensors. The customer's requirements state that each test machine needs to measure four SENT differential pressure sensors, each of which outputs two SNET signals (SENT1 and SENT2), requiring detailed differential pressure analysis.

A complete SENT signal is shown in the following figure:

A nibble represents 4 bits

A nibble can represent a value range of 0000~1111, 4 bits

The size of each nibble can be represented by the number of ticks. According to the protocol, the size of each nibble is represented by 12 to 27 ticks.

Tick ​​is a time unit, ranging from 3 to 10 us, usually at least 3 us

The sensor data is represented by the size of 6 nibbles

Sync pulse fixed at 56 ticks

Products used

hardware:

In view of the characteristics of SENT signals, Jianyi Technology chose the PCIe/PXIe-5211 board to achieve fast signal analysis. The PCIe/PXIe-5211 series modules are multi-purpose counter/timer modules with an internal clock frequency of up to 200 MHz, supporting 8-channel counters, and can perform multiple functions such as counting, frequency measurement, pulse width measurement, encoder, pulse output, etc. Through the pulse width measurement function, the SENT signal can be accurately analyzed, the starting Sync pulse can be identified, the tick time can be calculated, and the Status pulse, Data pulse, CRC pulse and Pause pulse can be further analyzed. The Data data is combined according to the information in the sensor manual to finally obtain the physical quantity signal output by the sensor.

software:

As a popular integrated development environment, Visual Studio C# provides powerful programming support and development tools for solutions, helping customers implement various complex functions and operations.

SeeSharpTools (Sharp Vision Measurement and Control Program Development Toolkit) is a unique resource of Jianyi Technology, providing customers with a wealth of development tools and support, allowing developers to use Jianyi products for development and testing more efficiently.