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    User name Templon

    Log entry time 16:15:47 on December 20,1999

    Entry number 31610

    keyword=cryotarg temp excursion

    Beam went off and cryotarget alarms sounded. Reason: pressure too high
    in loop. Reason: when beam went off, temperature dropped quickly and
    HP heater came on to compensate. Time constant of heater seems to be
    too small as heater overcompensates, thus pressure in cell loop goes from
    about 106 psi (beam on) to 100 psi (beam off, heater not yet on) to about 115
    psi (heater on at max). It just happened again during typing this message
    and this time the alarm was on temperature not pressure (perhaps i misidentified
    the previous error?) Temp goes up to about 7 K (setpoint 6.8 K) during event.
    Don't feel confident to make change in PID parameters myself.