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    User name Gomez

    Log entry time 11:32:55 on January12,2001

    Entry number 54436

    This entry is a followup to: 54416

    keyword=re: hallasc16 & dipole prob.

    Thanks to Kinney for the information. The main reason for this exercise is to determine if the observed fault is a new one or a known one waiting for a fix.
    It is fine to reboot the IOC whenerver one thinks it may solve a problem
    so that the experiment continues running.

    From previous entries regarding this problem, I will guess that the problem
    was the serial communication controller of the Dynapower (dipole)
    power supply - a known problem. These supplies have two internal controllers:
    one for serial comm. and another for internal signal control & monitoring.
    A bug has been found in the firmware of each of these controllers. For several
    reasons, fixing these problems requires to take these supplies completly apart
    and implement a totally new internal control system - something that is not
    planned for the inmmediate future.

    Both failure modes look similar. Open the corresponding dipole power supply
    screen. The ISET current field will change but the current readback will not.
    You may want to verify this by turning the corresponding field regulator (NMR screen) off and typing a new value for ISET (a few Amps above or below the
    shown value will suffice) and see if the current readback changes. Remember
    to put the field reg. back on after fixing the problem.

    If there is a problem, you could try the following in order of increasing severity:

    - Press either the "LEFT_ComRst" (LEFT spectrometer) or the
    "RIGHT_ComRst" (RIGHT spectrometer) button located
    towards the lower right hand side of the main controls screen.
    This attemps to reset all serial channels/devices. It takes ~ 30 sec

    - Reboot the IOC. During reboot, the IOC will perform the same reset
    procedure than above plus a few other than can not do while the IOC
    is normally running.

    - Call tech and tell him that it looks like the Dynapower Allan Bradley PLC
    is stuck with current in the magnet. Get, if possible, M. Stevens directly
    since he knows best the procedure to follow.