In the previous chapters you have created three variables in the "BoilerPlant/Boiler1/Data
" object, namely "Temperature"
. You write a number generated in the script of the timer "Emul"
every second into the "Temperature"
object. You change and influence the value of the power by moving the slider of the PmiSliderPane
item that you've placed in the window named "Panel"
For now you can watch the current
values of the temperature and change the value of the pressure of the boiler 1 manually.
It would be very handy to see the progression of measured values e.g. in hour, day, month range ..., in real time. It is also often required to display the data in a well arranged table.
All these requirements and many other tasks are handled in the PROMOTIC system by the trends system
means saving values of selected variables with the time stamp either in the memory and/or on the hard disk. These saved values can be presented in graphic or table form as time progressions of these variables or to use them for further analysis.
In the following chapters you will lern:
- how to add and configure the PmTrend
object into the application that manages trending of selected values
- how to define which variables
are to be trended
- how to create a panel for displaying the trends