National Instruments FieldPoint FP-1000 User Manual

Also see for FieldPoint FP-1000: User manual Quick start guide User manual Operating instructions Note to Users

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National Instruments FieldPoint FP-1000 User Manual Manual pdf 54 page image

Chapter 4 Installing and Using the FieldPoint SoftwareFieldPoint FP-1000/1001 User Manual4-16 ©National Instruments CorporationFor more information about the FieldPoint driver object class and datamembers, refer to the National Instruments FieldPoint section ofChapter 18, Object Class Reference, in your Lookout Reference Manual.Using the FieldPoint LabVIEW VIsWhen you install the FieldPoint software, a library of FieldPoint VIs iscreated if LabVIEW has already been installed on your computer. TheFieldPoint VIs (FP Open, FP Get Configuration Info, FP Create Tag, FPAdvise, FP Read, FP Write, and FP Close) directly access the I/O Itemsyou configured in the FieldPoint Explorer program. In addition, a set ofexamples is placed in your LabVIEW Examples directory. Theseexamples are the best way to get familiar with the LabVIEW VIs. TheFieldPoint LabVIEW Help document is in the same program group onyour Windows taskbar as the FieldPoint Explorer program. This helpdocument explains how to use the FieldPoint VIs.A simple FieldPoint application to read an I/O Item may only need touse four of the VIs. To create an example of such an application,complete the following steps and refer to Figures 4-8 and 4-9. Thisapplication reads the inputs from the I/O Item named All shown inFigure 4-1.1. Use FP Open to open the server. By default, the server opens withthe configuration file you last saved with FieldPoint Explorer.2. Use FP Create Tag to create a handle to an I/O Item that you definedin FieldPoint Explorer. You provide three string names to this VIto indicate which I/O Item you want access to. These three stringsare the names given to the communications resource, the device,and the I/O item. Figure 4-7 shows default names as they mayappear when you use the Find Devices button in FieldPointExplorer.3. Use FP Advise to continuously monitor the I/O Item at the ratespecified in FieldPoint Explorer. (You may also set a new rate withthis VI.) In this example, the while loop executes at this advise rate.If you used FP Read VI here instead of FP Advise, the loop wouldfree-run at the fastest rate it could sustain, reading the I/O Item overthe serial port each time the loop ran.Note: You should not put more than one FP Advise VI in a loop. All VIs in a loopexecute only once each time a loop runs, and FP Advise VIs only completeat their advise rate. If you had more than one FP Advise VI in the loop, theloop (and therefore all of the FP Advise VIs in the loop) would only execute