Timing Analysis - XMM-Newton

XMM-Newton On Board Time Wrap-Around Events

The table below contains all past CDMU Clock Events (either resets or wrap-around) as well as the next predicted wrap-around.

The current wrap-around period is: 16777404.30 secs (194 days, 04 hours, 23 minutes and 24 seconds), based on a drift factor (secs/count) of: 1.00001122326

The drift factor is not constant and has to be periodically re-evaluated; therefore, the prediction is within a few seconds of the real event (the table will be updated with the correct value after the event, and a new prediction will be made).

A CDMU reset brings the clock counts down to 0. In case of such an event, it will be reported in the table and a new wrap-around prediction will be determined. The reported times for CDMU resets indicate the time when the clocks resumed (although the CDMU problem had occurred earlier).

After a CDMU reset or a wrap-around the Instruments' clocks and the CDMU have to re-synchronized. This is either a manual Procedure or it automatically occurs at Instrument switch-on. The table indicates when the clocks re-sync took place for each event (and the potential impact associated with the delay between on-board clock re-start and Instruments' clocks re-sync).

Please view this PDF File for details on the 2000's resets.