Can I Use My DAQ Device's Internal 100 kHz Timebase as My Sample Clock? Hardware: Multifunction DAQ (MIO)
Problem: My appilication does not have any external sources that can be used as a clock. I do not want to create a sample clock using a counter and do not want to use another tasks' sample clock. Can I just use my DAQ device's internal 100 kHz timebase as my sample clock? Solution: Yes. Most National Instruments multifunction data acquisition cards have an internal 100 kHz timebase. This internal clock can be routed to be used as a sample clock. The way to route this signal may differ for different cards. With M-series devices, you can access this timebase by going to the Functions Palette and then selecting Measurement I/O » DAQmx Data Acquisition » DAQmx Advanced » DAQmx Constants & Property Nodes » Terminal Constant. After putting the constant on the block diagram, right click on it and select I/O Name Filtering. Turn on Include Advanced Terminals. You can now select your device's 100kHzTimeBase. Wire this to the source input of your DAQmx Timing (Sample Clock).vi. With E series devices you may have to route the signal using the DAQmx Connect Terminals.vi (be sure to disconnect the signal after use). For this, you will have to look at the Device Routes tab of your device in Measurement and Automation to see how the 100 kHz timebase can be routed. See more information on this in "Developer Zone Tutorial: Timing and Synchronization Features of NI-DAQmx" linked below. It is important to note that while this will work, the sample clock will be fixed at a rate of 100 kHz. Related Links: Developer Zone Tutorial: Timing and Synchronization Features of NI-DAQmx Attachments:
Report Date: 06/11/2007 Last Updated: 06/11/2007 Document ID: 4AAD7J0W |
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