National Instruments VXI-MXI-Express Series User Manual

Also see for NI VXI-8360T: User manual

National Instruments VXI-MXI-Express Series User Manual Manual pdf 32 page image

Chapter 3 Developing Your ApplicationVXI-MXI-Express Series User Manual 3-6 ni.comthe original NI-VXI API with regard to these settings. In particular, if youare receiving triggers on an external controller, you may need to modify thetrigger configuration on your extender module using MAX. Consult themanual for your extender module for details. In general, interrupts arerouted automatically based on the interrupt configuration the resourcemanager detects. Whether the changed routing behavior affects yourprogram is application dependent.Because VISA is an instrument-centric API, certain functions from themore controller-centric NI-VXI API do not match perfectly with a VISAcounterpart. When an application enables an event with the NI-VXI APIcompatibility layer, each logical address is enabled for that eventseparately. For example, if the application enables an interrupt level, VISAwill enable the interrupt on each logical address, one at a time, until all thedevices are enabled. This means that some interrupts could be lost fromdevices with higher numbered logical addresses. MAX provides anoption for users to pick which logical address is enabled first. Select Tools»NI-VXI»VXI Options. Set Prioritized Signal LA to the logical address ofthe device that generates the events. This prevents possible loss of eventsfrom that device.Device Interaction and Debugging ToolsNI I/O Trace and VISAIC are useful utilities for identifying the causes ofproblems in your application, and are installed by default with your NI-VXIinstallation.NI I/O TraceNI I/O Trace tracks the calls your application makes to National Instrumentsdrivers, including NI-VISA, NI-VXI, and NI-488. NI I/O Trace highlightsfunctions that return errors, so during development you can quickly spotwhich functions failed during a program’s execution. NI I/O Trace can logthe calls your program makes to these drivers so you can check them forerrors at your convenience, or use the NI I/O Trace log as a reference whendiscussing the problem with National Instruments technical support.Figure 3-1 shows an example of an error returned from a call toviMemAllocEx.