Unwired input

One of the inputs to the Formula Node is not wired. LabVIEW does not know what value to use for the parameter. For example, in the following illustration, the Y input parameter is not wired.

One way to correct this error is to wire a data input to the unwired input.

Another solution is to remove the input from the Formula Node by right-clicking the input and selecting Remove from the shortcut menu. If you choose this option, you might have to remove any reference to this parameter from the formula.