VeriStand Custom Devices Run-Time Errors

Issue Details

• Errors with custom device during run-time

Solution

• Simplify the custom device to the smallest reproducible case to isolate the source of the error
• If applicable, move the main custom device logic to a new real-time VI and test the functionality outside of NI VeriStand
• Add the NI VeriStand – Print Debug String VI to print strings to the console and trace the execution of the VI
• Use the Console Viewer to view any error information and determine the VeriStand engine state

Additional Information

First, verify that the error is caused by your custom device by determining that the error does not persist after removing your custom device from your system definition. 

If you verified that the error comes from the custom device, then the source of run-time errors or odd behaviors is from the RT Driver VI. This would include the Execute Model case of an inline model custom device, the Read Data from Hardware and Write Data to Hardware cases of an inline hardware custom device, and the contents of the while loop in an asynchronous custom device.

Custom device creation can be challenging, but there are several resources that can provide assistance along the way: 

• Initial Development – NI VeriStand Help: Creating Custom Devices
• During Implementation – NI VeriStand Help: Implementing a Custom Device
• Development Overview – NI VeriStand Custom Device Developer’s Guide

If you are encountering an error when adding a custom device to your VeriStand project or configuring a custom device in the System Explorer, please see Configuration Errors with NI VeriStand Custom Devices. If you are encountering an error during deployment, please see Deployment Errors with NI VeriStand Custom Devices. 

If you are still having problems with using the troubleshooting techniques mentioned above or understanding the custom device framework, please contact National Instruments support.