On Tuesday 11th October we installed the ITMX and ETMX hardware watchdog chassis (HWWD) in monitor mode, which completes the install of the four HWWD chassis.

Previously we had found that the ITMY HWWD reported LED-current-monitor undervoltages which were not been seen on ETMY. In the past 24 hours we have now seen similar events on ITMX, which suggests the longer cabling to the ITM systems may be a factor.

For the past 20 hours, I plotted the ITMX HWWD LED-current-monitor status against an OSEM coil drive signal (I chose top stage F1 as a representative example). There is a clear correlation between coil drive activity and the detection of a low voltage on the LED-current-monitor as seen by the HWWD (shows up as STAT_OUT = 8). I've attached two plots, one showing the two signals separately, on the other I have scaled the coil drive signal to a compatible Y-axis scale and plotted them together.