Civil Engineering Reference
In-Depth Information
object but also enables control and recording of the applied stimuli. In general, it
is recommended also to log all of the applied signals in order to achieve a com-
prehensive image of the complete test sequence. This enables the self-control and
the continuous consistency check as well as the later proof of the correct operation
of the test system. When only checking the output signals of the test object, the
only assumption can be concluded that all test scenarios had been applied properly,
which by no means can be recommended. In order to assure the reliability and
availability of the applied control and signal-recording devices, it is recommended
to apply calibrated and commercially available measurement technology only. This
allows a realistic and pure image of the applied test sequences.
6.4.4.4
Time Resolution, Sampling Rate and Buffers
The sampling rate or the time resolution of all devices shall be chosen so that a sig-
nificant over-sampling of all electrical and test-relevant signals is achieved. The ap-
plication of a device with a just sufficient performance can lead to problems if, for
example, another recording channel is required or another specific TC with a higher
time resolution is required. For any of the software modules of the CAN software
stack in this context, based on experience reaction times, time-outs, delay times
or intervals in the range of milliseconds are specified. Therefore, a test system is
recommended which allows a test coordination with tolerances in the range of some
few milliseconds. Of course, the applied measurement tools must be capable to read
CAN bus messages with a sufficient over-sampling rate to make them reproducible.
6.4.4.5
Test Control, Important Services and Test Installation in General
A test system must be able to perform various tasks, which are described subse-
quently.
On one hand, the applied test description method must be supported which is
either the execution at runtime or separation into a preparation phase, runtime phase
in real time and post-processing phase. An ideal solution is to not only allow the
interpretation of the test description at the runtime phase, but also support the prepa-
ration and post-processing phases in order to, e.g. initialize the test installation or
prepare time-critical phases for easy activation at later times. As such, the benefits
of both test-performing solutions are combined, whereas the real time capable in-
terface hardware typically does not allow the preparation of too many sequences
which can be either executed if required or even dynamically.
On the other hand, services are required for communication with UT/Lateral/LT
over different communication channels, data logging, test evaluation, presentation,
management, as well as for the control of various measurement devices, interface
hardware and stimuli generators. The aforesaid interface hardware can also serve as
part of a communication channel to the test system surrounding the test object, which
can be applied, for instance, for communication towards the UT of the host micro-
