After then, it was recovered at 11:15 on Apr. 29th (Mon.) JST but it was tripped again at 11:46 on Apr. 29th (Mon.) JST.
In both cases, a software watchdog detected the oscillation and saturation on the sensor signals of the MN stage (see also Fig.2 and Fig.3). This is just a matter of asking experts to check the control and/or sensors.
Guardian cannot escape from tripped states in automatically. So someone recovered ETMX once and ETMX tripped again. But I couldn't find any klog posts. It may be a more serious problem than a trip itself...
By the way, sound output of k1mon0 had been set as on-board speaker not a monitor connected via HDMI. Because of this, sound notification by VIS guardian couldn't be heard at all. It's my mistake on the settings of sound output when the system has been upgraded. This issue was fixed today.
I checked the reason why ETMX was oscillated.
Figure 1 and 2 show the signals of NB filters and MN DAMP filters, respectively.
DOF5 and MN_DAMP_L was oscillated at 5.1 Hz, which should be damped by DOF5.
So, it is very likely that the reason of the oscillation is DOF5 NB filter.
This filter was optimized when ETMX is at 90 K, so it is neccesary to optimize it again at the current temperature.
