Many LabVIEW nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in is NO ERROR error in is ERROR
If no error occurred before the node runs, the node executes normally. Then, if an error occurs while the node itself runs, it returns that error as the value of error out. If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.
Note

When a node responds differently to these values of error in, the differences are documented in the context help for the error in input of that node.