Data acquisition
Remark: For database logging, SQL server must be installed and the connection to the HMI must be defined.
It is possible to save the raw data to a database via HMI. Every I/O type except for markers, can be saved by opening the context menu of the I/O control by means of a right mouse click. When data is saved to the database a “disc” icoon is shown on the form and the logged Tag is presented bold. Digital I/O is saved everytime the I/O is changed, analogue I/O is polled and writen to the database. The polling frequency is determined by HMI and can be changed in the context menu. When the HMI is stop, the logging is also halted. Be aware that the information for Database logging is send to the board, so when the VB GUI is started again, the logging to the database will continue as long as the board isn’t reset or the logging is turned off by the user via de context menu. See also the example below.
Below the presentation of the database model. It is very simple. When a new Visual Basic HMI is started with a new name, the application will make a new row in the “Applications”-table. This also applies for the “Tags”-table. When a Tag is selected for DB logging and the tagname doesn’t exists, the programm will make an entry in the “Tags”-table with the tagname and the I/O-type. This will make the selection of the data easier. All raw data will be writen to the “RAW”-table. The only table that will not change is the “Datatypes”-table. It is recommented to never delete rows from this table. All tables are related. So when you delete a row from the “Applications”-table, all related rows in the “Tags”- and “RAW”-table are deleted.
Below a picure of the content of the “RAW”-table.
