is instrumentation and control engineering a core or non core branch?
Instrumentation and Control Engineering isn't a core branch. Its a applied branch and obviously an interdisciplinary branch of Electrical, Mechanical and Electronics engineering. Instrumentation and Control Engineering is a good field of study and you have a very good prospect in private sector.
For more information regarding Instrumentation and Control Engineering consider the link provided below:
https://www.careers360.com/courses/b-tech-in-instrumentation-and-control-engineering
I hope this helps. Wish you a great eve!