I was referred by an employee for whose consultancy I had done an undergrad project. I had to give an objective 4-option paper IQ test which had normal verbal ability and quantitative ability questions. Then after a day I was given a call for an interview. The questions in the PI were related to what I learnt overall in instruemntation engineering. The other stuff was related to project engg and management and some questions were directed to make an estimate of my knowledge of standards existing in the industry

Interview went good with initial aptitude test, then a group discussion with 8 to 10 people and then a personal interview round with the technical team. Selection was communicated by the end of the day.