High speed online measurement in endurance test for intelligent sensors. Test Object: In modern cars are often used intelligent Sensors. The once "simple sensors", such as pulse switch, reed relays or other sensors with partly analog signal output, now usually replaced by sensors that digitize the sensor signal directly and transmit it through a digital bus. The advantage obviously, the new features are self-diagnostics with error output, and a checksum during transmission, which allows advanced diagnostics and error location in modern cars. In addition, the serial busses saves wiring, certainly when the data is modulated on the power supply (this shrinks the automotive wiring).
However, these sensors also require much more effort in testing. In the past for testing the analogue sensor signals was measured directly by relatively low sample rates, but now digital bus protocols must be read and verified. This does not mean only, to read the bus protocol with standardized digital bus modules for checking the sensor signal (which was analogue in the past), but rather, the data stream itself has to be verified (bit length, levels, word length, times, periods, ...), because the sensor is specified with all of this data.
Test System: Our latest development is an endurance tester, which measures and checks online and parallel 20 of these sensors, during operation (wheel sensors - for ABS systems and to monitor the vehicle dynamics).
The test system checks all relevant characteristics of the sensors, such as bitstream in the digital protocol (times like the bit lengths, word lengths, periodic times ..., and the analogous values for voltage level - high / low level, fault level, etc., as well as the data protocol itself - error words, checksums, data selection, ...), the test is not done by taking single samples of each data stream, it is done online every single bit is checked all the time, for each of the 20 sensors (also more than 20 test positions are possible). In addition, the system will also assess the sensor signal itself, which means it will controls a drive (for weel-stimulation) and environment simulation chambers (there are the sensors located).
Because the data streams of such sensors is in the range of few 100kBit ... Mbps, a very high clocking analogue signal sampling and analysis is required. Our current developed system has a sampling rate of 50MSamples, simultaneous on each of the 20 channels! By
the way system, it's not only fast but also accurate, the signals are measured and verified online in a resolution down to millivolts and 1/10μs!
The test software on the PC user interface allows free programming of the test sequence and the whole endurance test. All parameters for the stimulation of the test samples, the environment simulation, the measurement, as well pauses and timeouts can be edited in
the test sequence. All measurement data files are stored on the PC and are usable by standard software.
This testing concept is applicable to all sensors of this type and varieties of such data protocols. Our testing device can check everything which encodes its data digitally and when all criteria of the sensor spec
have to be checked!
Components of the test bench:
-
Environment Simulation Chamber
-
Drive for the stimulation of the sensors (dependents to sensor)
-
Electronic rack: With high-speed measurement system, a powerful real-time system and industrial PC system for user interface and test data storage.
Development: This test system is a classical example for one of our custom solutions. If you are looking for a test equipment for your sensors / actuators, regardless of whether n-fold endurance or single-test- / measuring station, we will create especially for your needs our concept and provide it to you completely from one source - development - construction - manufacturing- installation and service!
