What are the Sequence control methods of multiple chiller plants?

main header return chilled water temperature along with Water flow meter reading on bypass line for sequencing down, main header supply chilled water temperature along with Water flow meter reading on bypass line for sequencing up. flow meter could be replaced with chiller Full load %.

The sequence is to have Chiller plants controllers that will operate the n=1 circuits depending on main header return chilled water temperature from chiller primary loop