SCADA Best Practice: Using Event Based Trigger

Every software has its best practice(s) of using. For Ecava IGX SCADA, there is a useful setting called “Triggered By”, which is a compulsory setting for several modules like Script. This setting determines how should the particular action or event be triggered.

Script module is very useful in SCADA projects, especially when you have specific conditions to meet or need to have advanced mathematics function for certain parameters, or other advanced functions to program. Now the question is, how do you configure to execute these scripts in your project? Do you need to keep them running for every second? The clever way here is to use event based trigger, i.e. trigger it by event instead of timer.

For instance, if you want to execute a calculation ONLY when a button in HMI is clicked, then you wouldn’t want to execute it when there is no action sent from the button. In that case, you should configure the script to be triggered by event. This will ensure the system to avoid unnecessary background operation that might drag the process time.


As shown in screenshot below, let’s say ‘calculation’ is a script to calculate some selected parameters from input devices. The requirement here is to only perform the calculation when the operator hits on “Start” button. So that it can capture the correct set of data for calculation execution.

scada best practice script trigger by action event

For this scenario, select “Tag” (instead of “Timer”) for the setting “Triggered By”, so that the script will only execute when there is a trigger to the selected tag’s value.