NI-DAQmx: NI CompactDAQ Module Synchronization

Many applications require precise control of timing and the ability to synchronize multiple operations on multiple modules. National Instruments Compact DAQ data acquisition devices provide excellent tools for synchronization and are well suited for these applications. This example program will demonstrate how to perform multiple analog input module synchronization with CompactDAQ. By modifying the physical channel labels on the example program “Acq&Graph Voltage-Int Clk.vi”, we can create sophisticated cDAQ module synchronization programs.

Steps:
1.  Create an analog input voltage channel.
2.  Set the rate for the sample clock. Additionally, define the sample mode to be finite and set the number of samples to be acquired per channel.
3.  Call the Start VI to start the acquisition.
4.  Use the Read VI to measure multiple samples from N Channels on the device.  Set a timeout so an error is returned if the samples are not returned in the specified time limit
5. Call the Clear Task VI to clear the Task.
6.  Use the popup dialog box to display an error if any.

Note:  Make sure that the physical channels for each module IO control are separated by commas.  For example, to synchronize cDAQ2Mod1/ai0 and cDAQ2Mod2/ai0, type in: "cDAQ2Mod1/ai0,cDAQ2Mod2/ai0" into the physical channel IO control.

Requirements

Filename: cdaq_module_synchronization.vi

Software Requirements

Application Software: LabVIEW Base Development System 8.0
Language(s): LabVIEW

Hardware Requirements

Hardware Group: CompactDAQ
Hardware Model: NI 9201, NI 9265, NI 9203, NI 9205, NI 9205 D-Sub, NI 9206, NI 9211, NI 9215, NI 9215 BNC, NI 9217, NI 9219, NI 9221, NI 9221 D-Sub, NI 9229, NI 9233, NI 9237, NI 9239, NI 9263, NI 9264, NI 9201 D-Sub
Driver: NI-DAQmx 8.3

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