Indus-2 is a synchrotron radiation source which is operational at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, India. The betatron tune measurement system is an essential beam diagnostic system for smooth beam operation of Indus-2 which is based on swept frequency excitation method. In this method, a lookup table is used for adjustment of excitation signal level in the drive system and selection of reciver parameters such as sweep rate and bandwidth. It is observed that, beam excitation levels are required to be calibrated regularly due to change in the operating parameters of Indus-2. To cater this problem of re-calibration, a new tune measurement system for Indus-2 is developed based on optimal control method using genetic algorithm. Multiple parameters and multi-objective control were required to develop this system. A variant of genetic algorithm (GA) is developed for online control of this system. In this algorithm, real valued variables are used and their boundaries are adaptively modified during the online optimization, hence this variant of GA is called as Adaptive Variable Boundary based Real Coded Genetic Algorithm (AVB-RCGA). This system provides comparatively better results as compared to the old tune measurement system. The new tune measurement system is faster with better signal to noise ratio (SNR) for entire range of machine operation.