Use the error in and error out clusters in each VI you use or build to pass the error information through your VI. The error clusters are located on the Controls»Array & Cluster palette. In most cases, source also identifies where the error occurred. If error in detects an error, the VI returns the error information in error out and does not continue to run.
Refer to Error Codes for a list of errors that LabVIEW reports for your platform. You can use the General Error Handler VI to define custom error codes and messages.
If there is an error this Case structure executes before reaching this VI. The VI does not execute the main code but instead passes the error information straight through the Case structure to the error out cluster. If there is not an error, the VI this VI creates a new report.