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    User name R. Michaels

    Log entry time 12:40:24 on January13,2002

    Entry number 80251

    Followups:

    keyword=DAQ deadtime.

    Datamon reported DT = 11% at 200 Hz DAQ rate. But this was wrong, and due
    to a recent bug associated with re-organization of scalers. Fixed. Now DT = 2%.
    ----
    The DT may still be a bit high, but this would be because we are not suppressing
    pedestals. The events sizes are 4.8 kbyte, about 4 kbyte coming from ROC4,
    so ROC4 is dominating the DT.
    ----
    Minor problem of deadtime calculation: We don't have T7 on the Left arm scalers,
    so it is ignored. E.g. if ps7=1000 and T7 rate = 2000, it is a 2 Hz accepted rate.
    If DAQ rate = 200 Hz, it is a 1% error in deadtime (this is the case, e.g. for run 1486).
    Need to fix this . Simplest fix for now: set ps7=huge. (But I believe T7 is on RCS
    scalers, so it's another way to recover.)