The tuning is performed at the end of the LOCKED_SSFS state.
An average over 10 samples of LSC_B4_56MHz_DPHI, monitoring the deviation from the optimal phase, is made with a buffer reinitialized if the the SSFS_LINE coherence (LSC_SSFS_LINE_COH) is not good for a 1 sec sample.
Once a meaningful value for LSC_B4_56MHz_DPHI is obtained then this is added to the actual value of the demodulation phase SSFS.B4_56MHz_phi0_offset to obtain the new setpoint.
Then the newly calculated setpoint is written back into SSFS.B4_56MHz_phi0_offset and saved permanently in the CARM_DARM_LOCK.ini config file as B4_dphi.
The new value of B4_dphi will be taken in account at the next transition to LOCKING_CARM_TO_MC.
The behavior of this new strategy has been checked over few transition through LOCKED_SSFS and seems fine.
