Tune Configuration - DLS-Controls-Private-org/MBF-docs GitHub Wiki
Configuration of tune fitting algorithm. All PVs are prefixed with$(device):$(axis).
Config
Most of the following control PVs should be left alone, as the involve adjusting hidden internal parameters of the fitting algorithm.
| Title | PV | Description |
|---|---|---|
| Max peaks | :TUNE:CONFIG:MAX_PEAKS_S | This determines how many peaks the fitter will attempt to find in the data before extracting the three largest and determining the tune. For LMBF this should be set to 1, for horizontal TMBF this should be set to 3, and for vertical TMBF it may be helpful to set this to 4. |
| Smoothing | :TUNE:CONFIG:SMOOTHING_S | Leave this set to 32. |
| Min height | :TUNE:CONFIG:MINIMUM_HEIGHT_S | Once a first peak has been found, all remaining peaks must be at least this high in relative units. Leave set to 0.1. |
| Data | :TUNE:CONFIG:WEIGHT_DATA_S | This selects the weighting of the model when fitting. Normally "Weighted" should be selected. The following options are available: |
| Name | Description |
|---|---|
| Weighted | The fit between the data and the model is weighted by the magnitude of the original data. This forces the model to fit more tightly to peaks and less tightly to the troughs. In practice this seems to produce a better result. |
| Unweighted | All data points are treated equally during the fit. |
| | Min width | :TUNE:CONFIG:MINIMUM_WIDTH_S | This is the minimum width of a peak which will be accepted. The width is in tune frequency units. | | Max width | :TUNE:CONFIG:MAXIMUM_WIDTH_S | Maximum acceptable peak width in tune frequency units. | | Min spacing | :TUNE:CONFIG:MINIMUM_SPACING_S | This parameter is used to reject fits where peaks have approached to close to one another. Best to leave set to 1. | | Max error | :TUNE:CONFIG:MAXIMUM_FIT_ERROR_S | The main function of this parameter is to reject tune fitting when there is no valid data to fit. Leave set to 0.2. | | Window start | :TUNE:CONFIG:WINDOW_START_S | This can be set to an offset into the detector sweep waveform to restrict the tune fitting to the part of the waveform starting at the specified offset. | | Window len | :TUNE:CONFIG:WINDOW_LENGTH_S | This can be set to the length of the window restricting tune fitting to part of the waveform. As a special case, a value of 0 written here will select the entire window. |