As Hugh reported ealier today, the hydrolic fluid pressure as read by the HEPI pump controller units dropped yesterday when the timing FPGAs were being reprogrammed. He also reported that this was seen the last time we reprogrammed the FPGAs on Tuesday 19th May 2015.

We are seeing other unrelated EPICS channels showing data issues around the time of timing upgrades. Attached are dataviewer plots (24 hours of minute trends) which show an EY vacuum gauge and the EY-HEPI pump controller's 4th  pressure sensor for 19 May 2015 and 19 July 2016. In both cases as the timing is being upgraded the fluid pressure appears to drop and the vacuum pressure appers to increase.

Investigation continues. We may ask for some EY downtime next Tuesday to see if this is reproducible and to more closely monitor what is changing. At this point we are assuming this is a sensor or read-out error and the vacuum/fluid pressures were not actually changed.