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Beside the period of validity, there are two other things you have to check to make sure your visa is still valid:
If your new stay would be allowed while respecting all these limitations then you can certainly do it with your current visa.
In particular, having a multiple-entry visa means that you have a lot more flexibility. You are only expected to submit a detailed itinerary and proof of travel insurance for the first journey on the visa and after that it's completely fine to use it for other purposes or destinations.
You should however carry all the documents you would need for a fresh visa application (e.g. itinerary, invitation, travel insurance). You will probably not need them but that would help showing your trip is completely legitimate if any doubt arises at the border.