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Configure OPC Client I/O Server Dialog Box

LabVIEW 2013 Datalogging and Supervisory Control Module Help

Edition Date: June 2013

Part Number: 371618J-01

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Requires: DSC Module

In the Create New I/O Server dialog box, select OPC Client from the I/O server type list and click the Continue button to display this dialog box. You also can right-click an existing OPC Client I/O server and select Properties from the shortcut menu to display this dialog box. Additionally, you can display this dialog box by double-clicking the Create and Configure IO Server Express VI, selecting OPC Client from the I/O server type pull-down menu, and clicking the Set Attributes button.

Use this dialog box to configure the instance of the OPC Client I/O server you want to use. This dialog box contains the following components:

  • Settings—Use the options on this page to configure the update rate, deadband, and reconnect poll rate of the OPC Client I/O server.
    • Browse—Specifies if you want to select a computer from a list of computers that use the NI Publish-Subscribe Protocol (NI-PSP) or a computer on the network.
    • Machine—Specifies the name of the computer from which you want to select an OPC server. Click the Browse button to navigate to and select a computer. This option is available only when you select Machine in the Browse pull-down menu.
    • Registered OPC servers—Lists the OPC servers installed on the Machine you specify. This option is available only when you select Machine in the Browse pull-down menu.
    • Prog ID—Specifies the ID of the OPC server. This option is available only when you select Machine in the Browse pull-down menu.
    • Update rate (ms)—Determines the amount of time that passes, in milliseconds, before the OPC server communicates updated values to the Shared Variable Engine (SVE). If the Update rate (ms) is less than the actual update rate of the OPC server, the OPC server communicates updated values using the actual update rate. Entering a value of 0 returns the fastest update rate possible from the OPC server. The default is 1,000.
    • Deadband (%)Sets the percentage that a value from the OPC server must change before the OPC server communicates the value to the SVE. The default is 0.
    • Reconnect poll rate (s)—Specifies how often, in seconds, the SVE attempts to connect to an OPC server after losing the connection to the server. Enter a value of 0 if you do not want the SVE to retry the connection. The default is 120.
    • Select an OPC server—Displays a list of computers on the network from which you can select an OPC server. This option is available only when you select Network in the Browse pull-down menu.
  • Advanced—Use the options on this page to configure advanced options of the OPC Client I/O server.
    • Server Instance Preference—Specifies the server to which the SVE first attempts to connect.
      • In process—Specifies that the SVE attempts to connect first to the in-process server, which is typically a .dll file. If the SVE fails to make a connection, the SVE attempts to connect to the out-of-process server.
      • Out of process—Specifies that the SVE attempts to connect first to the out-of-process server, which is typically an executable, or .exe file. If the SVE fails to make a connection, the SVE attempts to connect to the in-process server.
    • Write Method Preference—Specifies whether the SVE waits for the OPC server to process the write operation before continuing.
      • Asynchronous—Specifies that the SVE does not wait for the OPC server to process the write operation before continuing.
      • Synchronous—Specifies that the SVE waits for the OPC server to process the write operation before continuing. Enabling this option can cause slow response times and affect system performance.
    • Use Variable Engine timestamps—Specifies whether to use the SVE timestamps for the values that the OPC server communicates.
  • Diagnostics—Use the options on this page to log diagnostic information about the OPC Client I/O server.
    • Enable diagnostics—Specifies whether to log diagnostic information for the OPC Client I/O server. Enabling this option can cause slow response times and affect system performance.
      • Log file—Specifies the HTML files to which you want to save the diagnostic information about the OPC Client I/O server. The HTML file you specify in the Log file option logs the communication between the SVE and the OPC Client I/O server. The OPC Client I/O server generates a separate log file to log the communication between LabVIEW and the OPC Client I/O server. For example, if you specify a log file named logfile.html, the OPC Client I/O server automatically generates a logfile_LV.html file to log the communication between LabVIEW and the OPC Client I/O server.
      • Max size—Specifies the maximum size of the log files, in kilobytes. If the log files exceed the Max size, the OPC Client I/O server overwrites the oldest data with new data. The default is 10,240.
      • View log files—Displays the log files in the default Web browser.

 

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