Currently, I have a subscription for Cygnus for onchange. Is it possible to use ONTIMEINTERVAL? I want to get data from orionbroker to Cygnus after a certain interval, not just on change.
ONTIMEINTERVAL functionality was removed in Orion 1.0.0 which was released in March, 2016. If you need ONTIMEINTERVAL you can use the very previous version to it (0.28.0) but I don't recommend you to do that as it is a pretty old version.
Note the most efficent way to store information in Cygnus backends in when information change. The application using that data can be smart enough in order to "fill the missing gap".
For example, if you have in your storage that one measure was at 13:00 and the next one at 23:00 and you need to draw all the points in between with minute resolution, the part of your application on charge of the GUI web can deal with it just before rendeding the web page.