Getting Started with the LabVIEW Datalogging and Supervisory Control Module Manual

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

  • 6 | ni.com | Getting Started with the LabVIEW DSC Module7.Click Done to close the Multiple Variable Editor window.8.Select File»Save All and name the project library Tank System Shared Variables. LabVIEW binds the shared variables in the Tank System Shared Variables project library to the corresponding items on the network.Configuring Data LoggingWhen you enable logging for a shared variable, the DSC Module logs shared variable data, including the shared variable value, timestamp, whether the value is in an alarm state, and the quality of the value. The DSC Module can log data to the Citadel database or a supported relational database. In this exercise you will enable logging to the Citadel database for the Tank Level [Gallons] shared variable.Complete the following steps to enable logging for a shared variable.1.Right-click the Tank System Shared Variables.lvlib project library and select Multiple Variable Editor from the shortcut menu to open the Multiple Variable Editor window.2.Place a checkmark in the Logging:Enable cell for the Tank Level [Gallons] shared variable. Additional logging options appear as columns in the table. Make sure the Logging:Alarms and Events and Logging:Data cells contain checkmarks.The Logging:Alarms and Events option enables alarm and event logging for the shared variable. The Logging:Data option enables historical data logging for the shared variable.3.Enter 0.1 in the Logging:Resolution cell for the Tank Level [Gallons] shared variable. This value compresses the value to one decimal point when the DSC Module logs the values of this shared variable to the Citadel database.4.Leave the Logging:Deadband cell for the Tank Level [Gallons] shared variable with the default value of 0.01. This value specifies that the DSC Module logs the shared variable value only when the shared variable value differs from the previous shared variable value by 1% of the shared variable engineering scale range, which is 0–100 by default.Configuring AlarmingAn alarm is an abnormal condition on a shared variable or a user-defined condition. An alarm occurs if a shared variable value goes out of its defined alarm limits or if a shared variable has bad status. In this exercise you will add an alarm for the Tank Level [Gallons] shared variable.Complete the following steps to add alarming.1.Place a checkmark in the Alarming:Enable cell for the Tank Level [Gallons] shared variable. Additional alarming options appear as columns in the table.2.Place a checkmark in the Alarming:HI:Enable cell for the Tank Level [Gallons] shared variable. Additional options for the HI alarm appear as columns in the table. Notice that the default value of the HI alarm is 75, as shown in the Alarming:HI:Limit cell.3.Click Done to apply the changes to the shared variable and to close the Multiple Variable Editor window.