AsTrend module allows displaying, browsing and printing of time based graphs of selected set of variables and is also used for generating site operation graphical reports and diagrams. AsTrend can be operated as an integrated part of the visualization system or as a standalone application with access to data archive on the local machine or with a remote network access. 

 Innovative graph viewing method 

The AsTrend module allows quick identification of graph fragments of interest to the user thanks to the smart viewing method which arranges the graphs based on aggregated values calculated and archived by a special Aggregator module. Application of Aggregator module allows optimising the display of extensive time-range graphs. The graphs are drawn using aggregate values acquired from asix server archive, which significantly improves the speed and flexibility of presentation. AsTrend automatically matches the aggregate period to time range of the presented graph. As a result of plotting a curve with a time range of 12 months for an analogue value registered in the archive takes 2 or 3 seconds using typical hardware and the information showing the variability of the graph is not lost. 

 Wide range of presented data types

Various data types which can be presented on time based graphs offer many possibilities for process information analysis. In addition to analogue measurement values, graphs can also show:

• constants; 
• drive and device status acquired from archived status variables; 
• evaluated variables based on the value of up to 9 other variables; 
• information on the timing of alarm status changes; 
• data retrieved from external sources (*.csv, and *.xls files, MS SQL and Access database files); 

Moving across timelines is facilitated by the wide range of predefined data time ranges, such as: "last/next day", "last/next shift", " last/next hour", etc.; an option to describe the Y axis with the text labels representing status (for example sterilisation, pasteurising, product ejection, emergency ejection, washing) are especially useful for a clear process sequence presentation.  

 Two-dimensional X-Y graphs

AsTrend also offers a possibility of presenting and analysing the relationship between variables using two-dimensional X-Y graphs, which are essentially graphs of many asix variables as a function of a single independent variable. Furthermore, by adding a minimum and maximum, the range of allowable variable changes can be declared (also as a function of independent variable!), which allows placing the graph and analysis within the correct operating range of the controlled system. The option of plotting graphs for many dependent variables in X-Y arrangement is a unique feature of the asix package, which is unavailable in all other SCADA packages! This allows to easily create documentation for system analysis as a function of a single set-point signal. 

 Arbitrary arrangement of graphs from different periods

The possibilities offered by the graphical representation of data should also include a comparison of the same or different variables in different time periods. AsTrend makes this possible by the use of an additional time axis added for one of the variables whose time curve needs to be compared with that of another variable (it is also possible to compare time based curve of the same variable in two different time periods). 

 Individual scaling of graphs

The multiple OY axis mode makes it easier to analyse and compare curves representing different parameters on the same chart. The curves can be scaled independently allowing them to be moved away from each other which facilitates assessment of their interdependence.

The above feature is complemented by the following functions: intuitive trend wizard; value grid; extensive legend providing description of all presented parameters ; real-time zoom in/out function for a selected graph section; presentation of all data in a tabular form; exporting the data to*.PDF, *.BMP, *. TXT or a Microsoft Excel spreadsheet; importing data from external sources; displaying variable description as axis labels. 
 

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