During India's PSLV-C35 launch on 26 September 2016, mission control's launch sequence events (stage separations, stage ignitions, etc.) included 'CLG INIT'. What does it mean?
"CLG INIT" stands for "closed loop guidance initiation", and means that the launcher is switching into a mode where it actively steers based on its current trajectory rather than a fixed, unconditional program (referred to as "open loop guidance").
In the early part of flight, it is safer to use a "pitch-versus-time" or similar simple logic to guide the rocket. Weather events or errors in the measured trajectory might otherwise cause undesirable over-reactions in steering. Once out of the dense atmosphere, the launcher can correct for any difference between the desired trajectory and the actual one; the repeated process of measurement, error determination, and steering to correct the error is the "loop".
For PSLV, the CLG INIT occurs a few seconds after second stage ignition.