User Documentation

Data recorder
System manual
2696790000/02/04.2020
78
● When the profile state is being stored, large amounts of data can accrue,
depending on the size of the profile. If the application stores the state
cyclically at frequent intervals, this can significantly reduce the service
life of non-volatile storage. After the application controls the storage of
the states themselves, a sensible compromise should be sought here.
● Changes to the application can cause persistent settings of a profile to
become invalid if they reference variables that no longer exist. Invalid
settings, such as faulty trigger variables, result in the profile no longer
being able to be configured as it was originally. The application discov-
ers this through corresponding error messages. If, however, there are
only individual variables that are missing that have been registered for
recording, the profile is configured with the available variables as being
ready-to-use (and, if necessary, also started).
● If a profile is deleted, its persistent data is also deleted (configuration
and recording status). If the queue is deleted, the persistent recording
status is also deleted.
14.2 Data recording
Variables that are registered to a profile can be recorded. A recording con-
sists of
● capturing the values of all registered variables and
● the storage thereof (together with metadata) in the buffer.
The recording of the variables can be controlled in terms of time or event.
The data is stored in a buffer in conjunction with a time stamp. The buffer is
located in the RAM, but it can also be stored on a data carrier. The buffer
can be read out area by area, even during a running recording.
Recording can take place either manually or automatically. During automatic
recording, the following can be configured by means of the application:
● Temporal distance of the individual recordings in μs
● Task priority of the individual recordings (from 1 = high to 31 = low)
● CPU task binding (starting from 0, or -1, for system-side selected stan-
dard binding, > 1 CPU available for the runtime)
With these settings, a task is generated on the system side, which is queued
under the usual application tasks in regards to intermittency and priority.
Information
The interaction of these tasks with the usual application tasks must be
taken into account. For example, if the time stamps of the data detect un-
wanted “jitter,” the adopted configuration should be modified. Furthermore,
the priority should not be too high, the distance should not be too short and
the quantity of data should not be too large in order to prevent a blocking of
real-time-critical tasks.
A profile can occupy the following states: