How to Read, Validate, and Write CSV Data in TestStand

• Define a data container for CSV mapping
• Read input data from a CSV file
• Perform calculations and validation
• Write processed data to an output CSV file

• NI TestStand™ installed
• A CSV file with headers (for example: Input1, Input2, Input3, Input4, Input5, Expected)

• Navigate to the Variables pane.
• Create a container variable:
  • Name: Locals.RowData
  • Type: Container
• Add the following fields inside Locals.RowData:
  • Input1 (Number)
  • Input2 (Number)
  • Input3 (Number)
  • Input4 (Number)
  • Input5 (Number)
  • Expected (Number)
  • Actual (Number)
  • Result (String)
• Create additional variables:
  • Locals.InputStream (Object Reference)
  • Locals.OutputStream (Object Reference)

• Create a CSV file (for example, TestStand_Demo.csv) with the following header row:

  Input1, Input2, Input3, Input4, Input5, Expected
  

• Populate rows with numeric values.

• Add a New CSV Input Stream step in the sequence.
• Set:
  • CSV File Path → input file path (for example, D:\TestStand_Demo\TestStand_Demo.csv)
  • Input Record Stream Reference → Locals.InputStream
  • Separator Character → Comma
  • Enable Skip Lines = 1 (to ignore header row)

• Add a New CSV Output Stream step.
• Set:
  • CSV File Path → output file path (for example, D:\TestStand_Demo\TestStand_Demo_Out.csv)
  • File Open Mode → FileOpenMode_Truncate (Note: This helps to overwrite the existing file)
  • Output Record Stream Reference → Locals.OutputStream
  • Field Headers → Locals.RowData (Note: This helps to write the Header Row in the Output file in the same order mentioned in RowData container)
  • Separator Character → Comma

• Insert a Stream Loop step in the sequence.
• Configure the loop to read from Locals.InputStream.
• Map each row into Locals.RowData.

Add an Expression step inside the loop:

Locals.RowData.Actual =Locals.RowData.Input1 +Locals.RowData.Input2 +Locals.RowData.Input3 +Locals.RowData.Input4 +Locals.RowData.Input5

Add another Expression step:

Locals.RowData.Result = (Locals.RowData.Actual == Locals.RowData.Expected)? "Pass": "Fail"

Add a Write Record step inside the loop and configure as mentioned below to record the RowData to the Output CSV file.

• Execute the sequence.
• Verify that the output CSV file is created with additional columns for Actual and Result.

• The input CSV data is read row by row.
• The sum of Input1–Input5 is calculated as Actual.
• Each row is validated against the Expected value.
• The output CSV file contains:
  • Original inputs
  • Calculated Actual value
  • Validation result (Pass or Fail)