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Send Trigger to Instrument

Use visatrigger Function

You can execute a trigger with the visatrigger function. This function is only for VISA-GPIB and VISA-VXI interfaces. It is equivalent to the viAssertTrigger operation, as described in the VISA Specifications found at IVI Specifications. For an instrument connected with the VISA-GPIB interface, this function triggers the instrument using a GPIB bus event.

Refer to your instrument documentation to learn how to use its triggering capabilities.

Execute Trigger

This example illustrates VISA-GPIB triggering using a Keysight™ 33120A function generator. The output of the function generator is displayed with an oscilloscope so that you can observe the trigger.

  1. Create a VISA-GPIB object — Create the VISA-GPIB object g associated with a National Instruments™ GPIB controller with board index 0 and an instrument with primary address 1.

    g = visadev("GPIB0::1::0::INSTR");
  2. Write and read data — Configure the function generator to produce a 5000 Hz sine wave, with 6 volts peak-to-peak.

    writeline(g,"Func:Shape Sin")
    writeline(g,"Volt 3")
    writeline(g,"Freq 5000")

    Configure the burst of the trigger to display the sine wave for 5 seconds, configure the function generator to expect the trigger from the GPIB board, and enable the burst mode.

    writeline(g,"BM:NCycles 25000")
    writeline(g,"Trigger:Source Bus")
    writeline(g,"BM:State On")

    Trigger the instrument.

    visatrigger(g)

    Disable the burst mode.

    writeline(g,"BM:State Off")

    While the function generator is triggered, the sine wave is saved to the Ref A memory location of the oscilloscope. The saved waveform is shown in the following figure.

    Image of an oscilloscope screen displaying a sine wave in a MATLAB figure window

  3. Disconnect and clean up — Use clear to disconnect the instrument from the VISA-GPIB object g and to clear it from the MATLAB® workspace when you are done working with it.

    clear g

See Also

Related Topics