This value allows you to rotate or orient text for readability. By default, the software displays text in a readable manner and will not allow it to display upside down. For example, if you move a label in a direction that would affect the readability of the text, the software automatically flips the text so that it can still be read. Using Catalog Manager, you can disable this option and allow the text to display upside down if needed.
If setting this property from the Properties window in Smart P&ID, value of the Rotation angle of the selected symbol should be ‘0’ degrees.