Instrumentation Engineer ranges from designing, developing, installing, managing equipments that are used to monitor and control machinery. The demand is so high for this branch.

Instrumentation engineers may design devices like dynamometers for measuring torque, blood glucose monitors, aircraft sensors, and smoke detectors.
They also play essential role in every successful aeronautical research projects.
They find employment in manufacturing firms, defense contractors, biomedical companies, government, or work for private engineering firms.
Instrumentation engineers find employment in industries which improve efficiency, stability and safety of automated processes. The industrial sectors include
Public/Private firms,
R&D Departments
Steel Plants
Cement manufacturing
and there are many more job sectors.

Popular companies that hire are:
ABB
Invensys
ESSAR
Suzlon

The average package is about 4-5 lakhs yearly.

Hope this helps you.
Good luck.