VISA Resource Name Keeps Changing or Climbing

Issue Details

When opening a VI which looks for a VISA resource name, the resource name is inaccurate and keeps changing/incrementing - for example, ASRL5::INSTR does not result in a valid connection, then after refreshing the list, that resource is replaced with ASRL6::INSTR, then with ASRL7::INSTR, etc.

Solution

This issue originates from faulty enumeration, which is likely caused by an unstable connection or mismatch between the port number enumeration done by NI-VISA and the Windows OS. Reinstalling NI-VISA solves the issue.

• In NI MAX, go to Remote Systems >> Your RT Target >> Software >> Add/Remove Software. Find the NI-VISA package, uninstall and reinstall it.
• If you encounter an issue, you can format the Real-Time (RT) target using the Replication and Deployment Utility (RAD), LabVIEW's "Set System Image" VI or other utilities. Make sure that important data is first retrieved from the cRIO and to reinstall the NI-VISA package as well as other software after formatting.
  The instructions for each are described in Replicating and Deploying NI Real-Time System Images. 
• If you cannot use NI MAX to access the target device, you can connect to it through an SSH connection. This will allow you to format the target and then use NI MAX to add/remove software.
  See the following article for instructions: Formatting an NI Linux Real-Time Target From the Command Line (Linux Shell).

Additional Information

Note that SSH is enabled by default for NI Linux RT targets. If the target does not have the NI Linux RT OS, please see: “SSH Must Be Enabled on the Target” Message Displayed When Adding Software to NI Linux Real-Time Target From NI MAX to ensure that SSH is enabled on the target.