Getting Started with the LabVIEW Datalogging and Supervisory Control Module Manual

Chapter Creating a Periodic I/O Server

Getting Started with the LabVIEW Datalogging and Supervisory Control Module Manual
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Getting Started with the LabVIEW Datalogging and Supervisory Control Module Manual

  • Getting Started with the LabVIEW DSC Module | © National Instruments | 3You now have a project containing a project library. In the following exercise you will use the project library in the project to create a periodic I/O server.Creating a Periodic I/O ServerAn I/O server is an application that communicates with and manages input/output devices such as PLCs, remote input/output devices, remote Shared Variable Engines, and data acquisition (DAQ) plug-in devices. These I/O servers read selected input items and write to them on demand. The DSC Module can connect to any OPC-compliant I/O server and to many third-party device I/O servers. Refer to the LabVIEW Help for more information about creating such servers, such as EPICS, Modbus, and OPC I/O servers. You also can create custom I/O servers. In this exercise, you will build a periodic I/O server. The periodic I/O server will run as a service and publish NI Publish-Subscribe Protocol (NI-PSP) data items to the network. Complete the following steps to add the periodic I/O server to the project.1.Right-click the Tank System IO Server.lvlib project library in the Project Explorer window and select New»I/O Server from the shortcut menu. The Create New I/O Server dialog box appears.2.Select Custom VI – Periodic from the I/O Server Type list and click Continue. The Configure Custom VI – Periodic I/O Server dialog box appears.3.Click New to display the Select VI step of the Custom VI-based Server – Periodic Wizard.4.Complete the following steps to select the VI from th 2,e Opening and Running an 2,Example 2, exercise to convert into a periodic I/O server.a.Click the browse button and navigate to the labview\examples\lvdsc\Getting Started\Tank Simulator folder.b.Select the DSC Tank Simulator VI. c.Click Next in the Custom VI-based Server – Periodic Wizard to advance to the Select Controls and Indicators To Publish step.5.Complete the following steps to select the front panel objects you want to publish as shared variables. a.Remove the checkmark from the stop checkbox in the Controls list. You will publish the remaining controls and indicators.b.Click Next to advance to the Select Method To Stop The Server page.6.Complete the following steps to select the mechanism you want to use to stop the VI. a.Select Stop the following While Loops.b.Place a checkmark in the While Loop checkbox.TipClick View on block diagram to highlight the While Loop you select on the block diagram. Use this option if you have multiple While Loops on the block diagram to make sure you select the correct While Loop.c.Click Next to advance to the Configure Server Distribution Component step.