PXI and VISA Background

Based on PCI, both the CompactPCI and PXI standards define a modular backplane solution packaged in a rugged mainframe topology. PXI adopts CompactPCI and extends it by adding features for integrated backplane timing and triggering, a slot-to-slot communication bus, a common software structure, and more rigid environmental standards—all essential for instrumentation systems. Because PXI is based on the CompactPCI standard, you can use PXI and CompactPCI modules in the same system without conflict. Today, PXI and CompactPCI are widely used for computer-based measurement and automation applications. PXI and CompactPCI take full advantage of Microsoft OSs, giving you an easy-to-develop, easy-to-use platform for measurement and automation. Because PXI and CompactPCI use PCI as the data communication path, PXI and CompactPCI provide the highest performance measurement and automation platform available today.

The measurement and automation industry is adopting PXI as a standard platform. Until recently, the most common way to low-level program a PXI device was to use a Windows kernel-level driver. This process required not only extensive knowledge of the device register set, but also low-level knowledge of Windows programming. This development could be very time consuming, because users had to write a separate driver for each Windows OS. NI-VISA makes this process much easier by acting as the kernel-level driver for a device, thus eliminating the need for the user to develop a new Windows kernel-level driver. Using NI-VISA also eliminates the need for writing separate device drivers for each Windows OS, because NI-VISA is already cross-platform compatible under Windows. The NI-VISA Driver Wizard, one of the tools available with the full development version of NI-VISA, even assists you in the Windows setup of your device. Through the NI-VISA Driver Wizard, you can create a Windows setup (.inf) file, as well as easily set up how NI-VISA handles interrupts from your device. A detailed knowledge of the register set and register programming of your PXI/PCI device is still required, but development time is drastically reduced, because NI-VISA handles the low-level Windows programming for you.

Note  Previous versions of NI-VISA included the PXI Driver Development Wizard. USB support was added to NI-VISA 3.0, and the NI-VISA Driver Wizard replaced the PXI Driver Development Wizard.