I checked the FC GR SUS/VCO crossover as shown in the attached figure. The crossover is about 60 Hz which is much larger than the blue reference on December 2022. This higher GR SUS gain could cause the instability during the transition from GR to IR. I reduced the GR SUS gain from 1 to 0.5 and the crossover became similar to the blue reference. I updated the SQZ_FC guardian to change this gain. Let's see if this helps the recent failure of FC GR to IR transition.
The green sus gain was defined in GR_SUS_LOCKING state of SQZ_FC guardian as follows.
ezca['SQZ-FC_LSC_INMTRX_SETTING_1_6'] = 0.5
In the previous alog, I changed the green sus gain by changing this line, but I think it is more convenient to define it in sqzparams. So I modified this line as follows.
self.GR_GAIN = sqzparams.fc_green_sus_gain
ezca['SQZ-FC_LSC_INMTRX_SETTING_1_6'] = self.GR_GAIN
And I defined fc_green_sus_gain = 0.5 in sqzparams.
I defined self.GR_GAIN = sqzparams.fc_green_sus_gain also in TRANSITION_IR_LOCKING state.