Programmatically Poll the Overvoltage Detection on an NI 446xHardware: Modular Instruments>>Dynamic Signal Acquisition and Analysis (DSA)>>PXI-4462
Problem: I have an NI 446x connected to my input signals and reading data. In the Analog Input section of the NI Dynamic Signal Acquisition User Manual, it states that "you can programmatically poll the overload detection circuitry on a per channel basis to monitor for an overload condition." Where can I find this value to poll and how can I do so programmatically in LabVIEW? Solution: You can programmatically poll the overload detection circuitry of your DSA card using a DAQmx Read Property Node. You can use the properties Overload Channels Exists, which outputs a true Boolean if an overload occurs, and Overload Channels, which outputs a string indicating the affected channels.
To do this, place a DAQmx Read Node, which can be found on the Functions Palette » Measurement I/O » DAQmx » Read Node. You can then click on the property and select Status » Overload and then select either property.
In text based programming environments, the C functions that can be used to similarly poll the overvoltage protection circuitry are
DAQmxGetReadOverloadedChansExist(TaskHandle taskHandle, bool32 *data); and DAQmxGetReadOverloadedChans(TaskHandle taskHandle, char *data, uInt32 bufferSize); More information on these functions can be found in the NI-DAQmx C Properties section of the NI-DAQmx C Reference Help.Related Links: Attachments:  Poll Overvoltage Detection.png
Report Date: 03/03/2008 Last Updated: 10/09/2008 Document ID: 4J2AKR9G |
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