Free online XLSX to LVM converter

A LabVIEW application or measurement workflow may require an .lvm file instead of an Excel workbook. Converting the workbook produces a tab-delimited measurement file, not an editable copy of the original spreadsheet.

What the XLSX format is

.xlsx is Microsoft Excel's ZIP-based XML workbook format, used by Excel, LibreOffice Calc, and other spreadsheet software. It stores worksheets, cells, formulas, formatting, charts, data types, comments, and workbook metadata. XLSX files commonly contain reports, calculations, exported instrument data, and tables intended for further editing.

What the LVM format is

.lvm means LabVIEW Measurement File in the Documents category. It is a plain-text, tab-delimited format used to exchange measurement data with National Instruments LabVIEW. An LVM file contains a LabVIEW-specific header, column headings, and rows of numeric or textual values.

LVM is suitable when a LabVIEW VI expects measurement-file input and is easy to inspect with a text editor or spreadsheet program. It does not preserve XLSX worksheets, formulas, cell formatting, charts, merged cells, comments, or most workbook metadata. A workbook with several sheets normally requires a separate LVM file for each sheet.

How to convert an XLSX workbook to LVM

Using the built-in converter on 101convert.com:

1. Open the XLSX-to-LVM converter on 101convert.com; the conversion is available without installing software.
2. Upload the workbook and select the worksheet containing the measurement table if the converter provides worksheet selection.
3. Choose the option that treats the first row as column headings when the sheet contains channel names. Remove report titles, notes, and other non-tabular rows before conversion when necessary.
4. Select LVM as the output format, start the conversion, and download the resulting .lvm file.
5. Open the file in a text editor and check for the LVM header, the ***End_of_Header*** marker, tab-separated columns, correct channel order, and expected decimal notation before loading it into LabVIEW.

Do not upload confidential measurement data to a web converter. Use a local workflow for sensitive files.

Using LabVIEW: First export the relevant worksheet from Excel or LibreOffice Calc through File → Save As, choosing a tab-delimited text file. In LabVIEW, read that file with Read Delimited Spreadsheet VI, then write the resulting array with Write To Measurement File Express VI configured for the LVM format. Configure the writer's delimiter, decimal separator, headers, units, and time settings to match the source data.

Saving a sheet as tab-delimited text alone does not create a complete LVM file; an LVM header is required. LibreOffice Calc can produce the intermediate text file, but it is not itself an LVM writer.

Using a local Python script: This example reads the first worksheet and writes a basic LVM file. It assumes the first column is the X or time column.

import pandas as pd

input_file = 'measurements.xlsx'
output_file = 'measurements.lvm'
df = pd.read_excel(input_file, sheet_name=0, engine='openpyxl')

with open(output_file, 'w', encoding='utf-8', newline='') as f:
    f.write('LabVIEW Measurement\t\n')
    f.write('Writer_Version\t2\n')
    f.write('Reader_Version\t2\n')
    f.write('Separator\tTab\n')
    f.write('Decimal_Separator\t.\n')
    f.write('Multi_Headings\tNo\n')
    f.write('X_Columns\tOne\n')
    f.write('Time_Pref\tRelative\n')
    f.write('***End_of_Header***\n')
    f.write('\t'.join(str(column) for column in df.columns) + '\n')
    df.to_csv(f, sep='\t', index=False, header=False, lineterminator='\n')

Install the dependencies with pip install pandas openpyxl. Change sheet_name=0 to a worksheet name when needed. Set X_Columns according to the LVM reader if the first column is not an X or time value. Use Multi_Headings set to Yes only when the file contains the additional heading rows expected by the receiving LabVIEW workflow.

Quality and compatibility limits

• Convert formulas to calculated values before export when LabVIEW needs results rather than formula expressions. Recalculate and save the workbook first; cached formula results may be unavailable if the file was never recalculated.
• Check dates and times. Excel stores dates internally as serial numbers, while LabVIEW may require formatted timestamps or elapsed numeric time.
• Keep the decimal separator consistent with the LVM header and numeric values. A comma decimal convention can conflict with tabular parsing.
• Use one rectangular table per conversion. Blank cells, merged cells, colors, charts, worksheet layout, and cell comments have no equivalent in ordinary LVM output.
• Confirm that the output encoding is accepted by the LabVIEW reader; basic ASCII channel names and values provide the broadest compatibility.
• After importing, verify channel names, units, column order, sample count, X or time values, and timestamps. A file can be correctly delimited while still mapping measurements to the wrong channels.