The NI Publish-Subscribe Protocol (NI-PSP) networking protocol requires three background services that run on Windows outside of any NI applications.

The services include Citadel 4 Service, Citadel 5, PSP Service Locator, and Time Synchronization. In the Windows Task Manager, these services appear as lkcitdl.exe (Citadel 4), nicitdl5.exe (Citadel 5), lkads.exe, tagsrv.exe, and lktsrv.exe.
Note Do not stop these services while the LabVIEW Datalogging and Supervisory Control (DSC) Module or the Shared Variable Engine is running.

The DSC Module also installs the Microsoft SQL Server 2008 R2 Express, which appears as sqlservr.exe in the Services utility. The Microsoft SQL Server 2008 R2 Express and the background services run automatically. If you need to interact with these services, you can use the Services utility. On Windows operating systems, select Start»Run, enter services.msc in the Open text box, and click the OK button to launch the Services utility.