Extension of BOY XY Graph to historic data

[utzeln]

Trend displays shall be capable of showing historical data. And today only the BOY Data Browser widget is able to do that, not the XY Graph widget.

But we have a use case that requires to extend the XY Graph widget.We are designing faceplates for our main components - valves, pumps, electrical breakers... A faceplate is typically a tab container with a tab for monitors, a tab for trends and a tab for controls. A macro is used to make it configurable and reusable for different components/PV names. That is why we plan to use the XY Graph widget in the trends tab as we can configure the PV names with the macro. Defining a plt file for each valve, pump or breaker and use the macro to define the plt file name will be too much work. That is why we would like to extend the XY Graph to historic data.

A new “behaviour” property could be added in order to specify the time span on a XY Graph widget:

 Time Span (time_span): time span in seconds for historical data.

When no time_span value is found in the OPI, time_span = 0 is the default in
order to open existing OPI files without changing previous behaviour - i.e. no historic data plotted.

Another new “behaviour” properties need to be added in order to specify the data
sources:

 Use Default plt Data Sources (plt_data_sources): if yes, the URL of the

data sources are the ones defined for the data browser ordered by KEY.

If no, a new entry field is shown in each Trace properties to specify the URL of
the data source:

 Archive Data Source (archive_data_source): URL of the data source

The idea is to reuse the plugin org.csstudio.archive.reader to access archived data in general as it is done in the data browser.

[kasemir]

If you main concern is changing the PV names: The data browser allows changing PV names at runtime. So using the existing data browser opiwidget with a script that adjusts PV names, or with a script that constructs the complete model, might be the easier route than adding data browser functionality to the XYGraph.

If you prefer to change the XYGraph: When discussing the display builder update the leaning was always to work towards several specialized graph widgets instead of very few customizable but otherwise generic graph widgets. There are two main reasons for having a strip chart, waveform plot, scatter plot, image display, waterfall plot, .. instead of just an XYGraph & Intensity chart: The specialized graphs have fewer options and are thus easier to configure. For long term maintenance, they'll be easier to translate. Basically same idea for having a label, text update, circle, LED, .. instead of just a 'widget' where the text and border may be dynamically linked to a PV.