User Documentation

Data recorder
System manual
2696790000/02/04.2020
77
Buffer capacity
The buffer capacity defines the maximum number of stored variable values
with a time stamp that a profile can store. The recording process reads out
the values of all registered variables and writes these into the buffer of the
profile along with a time stamp. This data record (variable value with time
stamp) is called "Sample".
The buffer capacity multiplied by the maximum number of variables deter-
mines the storage requirement of a profile. The memory must be created be-
forehand in order to ensure recording in real time.
Buffer type
The following types of buffers can be configured:
● Continuous (endless recording): Recording beyond the buffer capacity
is possible by starting from the beginning once again after the last entry.
It is possible that overwriting unread samples may result in the loss of
data. When reading data, data should be checked for completeness.
● SingleShot (individual recording): no recording beyond the buffer ca-
pacity. At the latest, the recording ends when the end of the buffer is
reached. No data loss, no verification of the completeness of read data
necessary.
Persistence
By default, configurations and stored data are not kept after the system is
restarted. However, this can be changed by configuring the data recorder.
The following configurations are possible:
● No persistence: Each time the application starts-up, the profile is newly
created by the application and the recording starts with an empty buffer.
● Persistence of the configuration: The profile settings are stored in a file
under the path {System.applPath}/application/control/config. In
the course of the start-up of the control, the profile is automatically cre-
ated according to the configuration. The recording starts with an empty
buffer. The data is not persistently stored. If the autoStart option is se-
lected when the profile is created for the first time, recording is automati-
cally started during start-up.
● Full persistence: All information (configuration, as well as data that is al-
ready recorded) is persistently stored. The state and data are binary-
stored in the directory {System.applPath}/retain. In the course of the
start-up, the profile is automatically created according to the configura-
tion, and is put into the state that it was it at the last point in time a save
operation was carried out. If the autoStart option is selected, the
recording continues.
With regard to the persistence, the following shall be observed: