Select Programming Mode Dialog Box

Use this dialog box to select the programming mode you want to start programming the system with. You can change the programming mode later using the CompactRIO Chassis Properties dialog box. The Select Programming Mode dialog box appears when you add a chassis that supports the Scan Interface to your project and you have the LabVIEW FPGA Module installed on the host computer.

Scan Interface Mode

Scan Interface mode enables you to use C Series modules directly from LabVIEW Real-Time. Modules that you use in Scan Interface mode appear directly under the Chassis item in the Project Explorer window and I/O channels appear as I/O variables under the modules. To use I/O variables, you drag and drop them to LabVIEW Real-Time VIs.

In Scan Interface mode, you do not need to do any LabVIEW FPGA development or program communication between FPGA and Host VIs. You also do not need to wait for VIs to be compiled to the FPGA before deploying and running them. In Scan Interface mode, LabVIEW programs the FPGA on the CompactRIO target to work with the variables.

LabVIEW FPGA Interface Mode

LabVIEW FPGA Interface mode enables you to use C Series modules from LabVIEW FPGA VIs. Modules that you use in LabVIEW FPGA Interface mode appear directly under the FPGA Target item in the Project Explorer window and I/O channels appear as FPGA I/O items under the FPGA Target. To access the I/O channels, you configure FPGA I/O Nodes in FPGA VIs.

In LabVIEW FPGA Interface mode, you can use LabVIEW FPGA programming to add more flexibility, customization, and deterministic timing to your applications. To use the CompactRIO system in LabVIEW FPGA Interface mode, you must either have the LabVIEW FPGA Module installed on the host computer, or have access to a compiled bitfile that you can download to the FPGA. In either case, you use the Open FPGA VI Reference function in a host VI to access the FPGA VI or bitfile.

In LabVIEW FPGA Interface mode, you can still use the Scan Interface for some modules. 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. You may want to use the chassis in FPGA Interface mode and some modules in Scan Interface mode if, for example, you need more than two modules to do specialty digital functions. 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. You must ensure that the bitfile is running on the FPGA before accessing I/O variables.

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.

Note  If the chassis is in LabVIEW FPGA Interface mode, having modules directly under the Chassis item uses two DMA channels.