Are Beckman Coulter LMD files unique?

Yes.  They are unique because Beckman Coulter LMD files acquired on the FC 500, Gallios™, and Navios™ platforms actually contain two datasets within the file.

  • The first dataset, referred to as Dataset #1, is 10-bit FCS 2.0 analog data.
    • The linear parameters for this data are displayed on a 1 – 1024 scale, whereas the fluorescent parameters are displayed on a 4 decade log scale.
    • This is the dataset that is displayed in the acquisition software during collection.
    • The first dataset is also the default dataset that FCS Express will use to display LMD files.
    • Dataset #1 within the LMD file is compensated data.  The file is exported with the raw event values reflecting compensated values.  Therefore, compensation is essentially “baked” into the data.
    • This is why when Dataset #1 LMD files are loaded into an FCS Express layout, you will not see a compensation matrix loaded into the Loaded Automatically with Data Files folder of the Compensations window.
    • Manual compensation can still be performed on Dataset #1 but may cause digitization errors.
  • The second dataset, referred to as Dataset #2, is 20-bit FCS 3.0 linear digital data, with the scatter and fluorescent parameters displayed in their full 20-bit range, which has a maximum value of 1,048,576.
    • Hybrid scaling can be used with this dataset and negative values can be seen.
    • You will also be able to view and manipulate the compensation matrix that is imported with this data.

You can choose which dataset to use in the FCS File Options category of FCS Express User Options.  Users can decide to analyze one or both datasets in FCS Express.

To have access to both datasets, you will need to check the box next to Allow Multiple Datasets.  Leave the box unchecked to always select a single dataset. Enter the data set you wish to use (1 for Dataset #1 or 2 for Dataset #2) in the Default Dataset to use edit box.

Also, the Advanced Open Data Dialog option will need to be selected to provide the user with the option of which dataset to choose for display.  The option to display this dialog can be found from the FCS Express User Options, under Dialogs > Open Data Dialog.

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