29-05-2013, 11:37 AM
Data Set Logger Tutorial for LabVIEW DSC Module
Data Set Logger.pdf (Size: 179.73 KB / Downloads: 21)
Overview
With the LabVIEW Datalogging and Supervisory Control (DSC) Module, you can organize your historical data into data sets. A data set is group of tag values that are logged together during some
finite time period. A data set might cover a batch of some sort and contain all the values generated during a single execution of a batch process. For example, on the picture below, three tests were
performed on a motor to measure the motor response on a triangle-like setpoint function. The red graph represents the setpoint value; the white line is the motor response.
There are two tags configured in the .scf file. MotorRPMSetPoint holds the setpoint value, and MotorRPMSensor represents the motor response. In the DSC Module, both tags are logged to the
historical database, and all their values can be retrieved by either the Historical Data Viewer in MAX or the historical data VIs. So, how does the Data Set Logger, shipped with the DSC Module,
make it better?
The Data Set Logger marks the beginning and the end of each test with special markers. The data between the start and end points is called a run. Each run is identified by its ID. In our motor
example, one test corresponds to one run. As you can see from the picture, there are three runs stored in the database. Their IDs are Run 1, Run 2, and Run 3. The DSC Module provides
functionality to retrieve data from the database based on a run ID. This means that you don't have to remember what time the tests were executed. You don't even have to remember how many
tests have been executed. All this additional information is logged by the Data Set Logger to the historical database. With a single VI, you can retrieve the list of runs. With another VI you can
retrieve data from that run.