Default Transfer Mechanism -- MIO Devices Primary Software: LabVIEW Modules>>Real-Time ModulePrimary Software Version: 7.1 Primary Software Fixed Version: N/A Secondary Software: N/A Hardware: Multifunction DAQ (MIO)>>E Series
Problem: What is the default transfer mechanism that real time (RT) uses for all MIO devices? Solution: With the hardware timed single point mode, RT uses DMA as the default transfer mechanism for optimal performance for all MIO devices. On Windows, DMA is the default for 12 bit devices, but for the 16 bit devices, the default is programmed I/O. Due to certain complications in the architecture, DMA is not supported for hardware timed single point operations on 16 bit boards under Windows. DMA is supported for this mode with 16 bit boards in RT. Therefore, a hardware timed single point application written for a 12 bit board in Windows may have different performance when run on a 16 bit board because the data transfer mechanism is changed behind the scenes. Also, an RT or 12 bit Windows application that explicitly sets the data transfer mechanism to DMA will generate an error when run on a 16 bit board in Windows. Related Links: Developer Zone Tutorial: Data Acquisition Fundamentals Products and Services: LabVIEW Real-Time Developer Zone Tutorial: DMA Attachments:
Report Date: 04/19/2004 Last Updated: 12/20/2007 Document ID: 38I7PDCH |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
