Using the Scan Interface with Individual Modules

CompactRIO Reference and Procedures Scan Interface

Edition Date: July 2010

Part Number: 372603F-01

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You can use the Scan Interface for supported individual modules even if the chassis you are using is in FPGA Interface programming mode or does not support Scan Interface programming mode. In the Project Explorer window, drag and drop a module to the Chassis item to use the Scan Interface for that module, and drag and drop a module to the FPGA Target item to develop FPGA VIs for that module. Even if the chassis you are using supports Scan Interface programming mode, you may want to use the chassis in FPGA Interface programming mode and some modules in Scan Interface mode. For example, you may need more than two modules to do specialty digital functions, or you may want access to I/O for some modules directly from LabVIEW Real-Time and access to I/O for other modules directly from LabVIEW FPGA. When you compile the FPGA VIs, the resulting bitfile downloaded to the chassis includes the logic needed to communicate with modules using the Scan Interface.

If you have both LabVIEW Real-Time and LabVIEW FPGA installed, you can create user-defined I/O variables to transfer custom I/O data between FPGA VIs and RT VIs. You can also synchronize the execution of code in FPGA VIs and RT VIs.

Note Note  If the chassis is in LabVIEW FPGA Interface mode, you must always use the Open FPGA VI Reference function to download a compiled bitfile to the FPGA before using the I/O variables of modules that are directly under the Chassis item. You must ensure that the bitfile is running on the FPGA before accessing I/O variables.
Note Note  If the chassis is in LabVIEW FPGA Interface mode and there are modules or user-defined variables directly under the Chassis item, two DMA channels are reserved and cannot be used for FPGA FIFOs.
Note Note  If any modules are directly under the chassis item, you cannot write to the Sleep channel of the FPGA target.

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