ADwin Systems Perform at Microsecond Accuracy
In the automotive industry, the development of Electronic Control Units—ECUs—is critical in the manufacture of new vehicle models. This includes ECUs used in ABS, airbags, powertrains, suspension, drivers and other devices. Safety, comfort, and increased market competitiveness are the major factors driving new ECU developments. In this brief example CAS DataLoggers shows how ECU test development can significantly benefit from ADwin data acquisition and control systems.
ECU Test Requirements:
Comprehensive ECU tests are important to verify the units’ functionality. Because of the complexity of today’s ECU software, engineers and technicians must perform real-life test drives. Endurance tests in combination with environmental tests in terms of vibration, temperature, humidity, etc. give proof of the ECU’s functional stability. As a result, an ECU can only go into production if it is capable of handling all desired situations and stresses.
For these automotive test applications, the ADwin product family offers several systems for functional ECU testing and for other devices like CAN-based units, sensors, actuators, etc. These tests are performed in development of such devices as well as in production for quality assurance.
Using an ADwin system, analog/digital signals and inputs/outputs of the ECU under test can be acquired and the timing of all signals and messages can be evaluated online at microsecond accuracy. ADwin’s Input/Output response time is on the order of 1 microsecond. In this way users can completely test the control device.
Example of an Automatic Test for ECUs:
The ADwin system tests the control units with the help of generated multi-channel test signals by stimulating the control unit’s inputs with analog or digital signals. These test signals can be periodical or non-periodical (measured values from real test drives). In parallel to that, the outputs of the tested control unit are monitored simultaneously to the stimulation and evaluated online in order to verify whether the stimulation and the control device’s response correspond to the specifications. In this way, a single device stimulates the ECU test unit, measures the response and makes an online evaluation.
If the control unit has additional interfaces like CAN-bus, SPI, RS-232/xx or others, signals on these lines can also be included into the ECU test run.
A variety of communications options are available with ADwin. Typically in R&D applications, the ADwin measurement system is connected to a PC via Ethernet or USB to exchange results and start a test run. Meanwhile for production line applications, operators often use an Ethernet or fieldbus interface like Profibus. As mentioned above, ADwin can also interface with CANbus.
If standalone operation is desired, an available boot option allows for fully functional operation independent of any PC or external computer.
Sensor & Actuator Testing
Tests for sensors or actuators follow the same procedure described above. With ADwin it is possible to make test runs for a wide variety of different automotive devices.
The ADwin Advantage:
ADwin Real-Time data acquisition and control systems offer many competitive advantages stemming from their faster sampling and control:
- Very fast response time of 1 usecond or less
- Sample rate of 100kHz aggregate, to 1.25 MHz per channel
- High speed PID loops—up to 100 kHz or more advanced control functions
- Operation independent of the PC—the system will continue to run even if the PC stops
- Tightly-coupled analog in/out and digital in/out
Unique ADwin features include:
- Local processor with real-time operating system that runs independently from Windows CPU
- Easy to use program development tools with support for up to 10 processes
- Interface library for all of the most common GUI and development packages (VB, VC, Labview)
Data Acquisition Software:
ADwin provides all the benefits of direct software connection with Windows without the risk of OS lockups and crashes.
The ADwin software environment can be used under Windows (95/98/ME/NT/2000/XP/Windows 7) and LINUX or as a stand-alone data acquisition system. ADwin also has drivers for many of the popular programming environments including VB, VC/C++, LabVIEW, TestPoint and others.
Users are free to develop their test stand application with a full set of available drivers providing for full integration with other applications and programming languages.