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File Formats

How to open files in Cute Plot, what formats are supported, and what to do if something goes wrong.

Opening Files

File Menu

  1. Click File → Open
  2. Select one or more files
  3. Files load automatically

Drag and Drop

Drag files directly from your file explorer onto the Cute Plot window. You can drop multiple files at once. If a template is active, it applies automatically to newly loaded files.

Supported Extensions

Extension Format Lazy Loading
.csv CSV (comma, semicolon, or tab-separated) Yes
.xlsx, .xls Microsoft Excel No
.parquet Apache Parquet Yes
.inf + .out PSCAD simulation output Yes
.out PSS/E dynamic simulation output No
.psout PSCAD binary output (Windows only) No
.dat Blackbox RTS measurement data No
.cuteplot Cute Plot workspace (save/load sessions) —

Format Details

CSV (.csv)

The most common format. Cute Plot expects a header row, with the first column as time or index values and remaining columns as numeric data.

Time,Voltage,Current,Power
0.0,230.1,10.5,2416.1
0.1,229.8,10.4,2389.9
0.2,230.3,10.6,2441.2
  • Delimiters: Comma and semicolon are auto-detected.
  • Encoding: UTF-8. Other encodings may load with minor character issues.
  • Non-numeric columns: Skipped automatically (you will see a notification).
  • Duplicate column names: Renamed with _1, _2 suffixes.
  • SMA solar inverter CSVs: Auto-detected and handled, including multi-row headers and European decimal separators.

Excel (.xlsx, .xls)

  • Each sheet is loaded as a separate file in the sidebar.
  • Header rows and metadata rows are auto-detected and skipped.
  • Timestamp columns are identified by name, type, or pattern.

Parquet (.parquet)

Apache Parquet columnar files load directly. Good for very large datasets since lazy loading is supported.

PSCAD (.inf + .out)

Open the .inf file. Cute Plot finds the matching .out files in the same directory automatically. Both files must be in the same folder.

PSS/E (.out)

Binary PSS/E dynamic simulation results. Cute Plot distinguishes these from PSCAD .out files automatically based on the file header.

Blackbox RTS (.dat)

Binary measurement data with DT# timestamp markers. Both the original 6-channel format and the newer PQV format are supported, with automatic endianness detection.

PSCAD Binary (.psout)

Supported.

Datetime Handling

If your first column contains datetime strings instead of numeric time values, Cute Plot converts them to elapsed seconds automatically. The following datetime formats are currently supported:

Format Example
YYYY-MM-DD HH:MM:SS 2024-01-15 14:30:00
YYYY-MM-DD HH:MM:SS.ffffff 2024-01-15 14:30:00.123456
DD/MM/YYYY HH:MM:SS 15/01/2024 14:30:00
DD/MM/YYYY HH:MM:SS.ffffff 15/01/2024 14:30:00.123456
DD/MM/YYYY hh:MM:SS AM/PM 15/01/2024 02:30:00 PM
MM/DD/YYYY HH:MM:SS 01/15/2024 14:30:00
MM/DD/YYYY HH:MM:SS.ffffff 01/15/2024 14:30:00.123456
YYYY/MM/DD HH:MM:SS 2024/01/15 14:30:00

More datetime formats will be added over time, as well as automatic parsing.

Large Files

Cute Plot automatically switches loading strategy based on file size:

  • Under 2 GB: The full file is loaded into memory. All series are available immediately.
  • Over 2 GB: Lazy loading kicks in. A 200-row preview loads first, and full data is fetched on demand when you plot a series. Only CSV and Parquet files support lazy loading.

In future, this 2 GB value may be made a setting, however for general use, lazy loading hasn’t been required if you have sufficient RAM (16 GB+).

File Management

  • Rename: Right-click a file in the sidebar → Rename File. Changes the display name only.
  • Close: Right-click → Close File. Removes the file and all its series from the session.

Troubleshooting

File does not load

  • Make sure the extension is one of: .csv, .xlsx, .xls, .parquet, .inf, .out, .dat, .psout
  • For PSCAD files, open the .inf file and ensure the .out files are in the same directory.
  • For PSS/E .out files, verify the file has a valid binary header.

Columns are missing or empty

  • Non-numeric columns are skipped. If your data has text columns mixed in, those will not appear.
  • Check the notification bar for messages about skipped columns.
  • Ensure your CSV has a header row. Without headers, columns may not load correctly.

Datetime column not recognized

  • Check that your datetime format matches one of the supported formats listed above.
  • The datetime column must be the first column in your file.
  • Colons used as microsecond separators (e.g., 14:30:00:500000) are handled automatically.

Large file is slow to load

  • Files over 2 GB use lazy loading for CSV and Parquet. Other formats load fully into memory.
  • Close files you are not actively using to free memory.
  • 16 GB+ RAM recommended for large files.

Wrong delimiter detected

  • Cute Plot auto-detects comma and semicolon delimiters. If detection fails, check that your CSV uses one of these consistently.
  • Tab-separated files should also work, but comma or semicolon are most reliable.

Requesting a New Format

If you need support for a file format that is not listed here, get in touch at hello@cuteplot.com.