TestStand Error: Specified Value Does Not Have the Expected Type

Updated Jun 14, 2019

Reported In


  • TestStand

Issue Details

While creating a step in TestStand that requires an expression, I see the following error:


This error is produced when TestStand is unable to evaluate an expression due to the detected combination of operands and operators.

For example, the + operator may operate on both strings and numeric types, and depending on how a particular expression is written, TestStand may not be able to reliably cast one data type to another.

To resolve the issue, review your expression for any potential type conflicts. One good practice is to always use + operator for addition, and the & operator for string concatenation to avoid confusion.

Additional Information

It is also possible to explicitly cast one data type to another through tools like the Str() function in TestStand.


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