You are using Visual Flow Creator to create logic which handles MindSphere Timeseries data.
As a basic method to trigger the flow, you can use "inject" node. You can manually click the "inject" node or you can set repeat interval at the "inject" node.
Now you want to trigger your flow when Timeseries data is updated without loop polling the changes.
Solution
For that purpose, use "subscribe timeseries" node under "mindsphere".
In the node edit window, you can select assets, aspects and variables to be subscribed.
Once it is subscribed, the node will be triggered when the selected asset, aspect, variables are updated.
Notes
MindSphereVisual Flow Creator - Usages of MindSphere nodes
Subscribe timeseries node