TroubleshootingΒΆ

Some typical errors have been identified up to now:

  • Pattern device suddenly crashed, and could not be re-instantiated due to continuous initialization failures. This is typically due to the device encountering unexpected property changes in the DOOCS side, e.g. reset of patterns.

    Possible solution: In this type of cases the instrument can do really nothing, except getting in contact with the DOOCS responsibles via DOC (9-8089), or LAS colleagues,

  • The configured PPL pattern appears not to be applied. After pushing it to DOOCS the patterns displayed in the graphs are not changed. Possible scenarios are:

    • It happens sometime that the slot Write Pattern Sequence to Doocs is pressed instead of Write Patterns to Doocs.

      Possible solution: activate the configured pattern by pressing the slot Write Patterns to Doocs,

    • Everything was done correctly, but the Boolean Is Custom Pattern Enabled in the scene is false. In this case the machine is running in the so called Legacy mode which does not follow the user setting. This should not happen during run operations; if that is the case please contact the DOOCS responsibles,

  • The pattern was configured for a pattern type, e.g. A, which is not present in the running pattern sequence, e.g. [B]2[C].

    Possible solution: activate the proper pattern sequence which contains the configured pattern type,

  • The generated patterns differ from what expected from the pattern configuration saved in DOOCS; sometimes also zero pulses are observed in the instrument hutch or in the LAS diagnostics. The pulse frequency is not being compliant with what allowed by the frontend base frequency shown in the device. Look at the frequency lookup table for the allowed frequencies to be used, according to the base frontend frequency. Possible scenarios are:

    • The base frontend frequency was modified in the hardware and the currently active pattern is no more in the grid.

      Possible solution: If you are sure that the new displayed frontend frequency is correct

    then the patterns should be reconfigured with respect to that value.

    • No communication could be established by Karabo to the frontend hardware, and a wrong value for the frontend frequency was accidentally set in the pplPattern device. The active pattern appears mistakenly to be not in the grid.

      Possible solution: The correct frontend frequency value should be set by LAS colleagues in the device,

  • The generated patterns do not show pulses expected at the end of the configured pattern. This is typically due to the property Complete Target Burst Duration being larger than 600 microseconds, which is the maximum interval the Pockels cell can stay with voltage high to let pulses propagate and get amplified and delivered to the instruments.

    Possible solution: Configure patterns with smaller burst duration,

  • The subpattern pulse frequency (Pulse Freq.) is displayed as a NaN (not a number). In the current code implementation this is not an error, is normal and is due to the number of laser pulses being smaller than two. In this case, also the interval between two pulses (Pulse Interval) and the number of empty bunches between pulses (Inter-Pulses Empty Bunches) cannot be measured and are set to NaN and zero, respectively.