My USB delivers continuous voltage output after stopping VI also?

[kirupacae@gmail.com]

Hello friends,

I am using USB 6229, USB 6009 etc., for my application. I am generate the analog output volatge from it. After stopping the VI, even after closing labview also my USB device delivers the output. Please help to solve the problem.

Kindly advice.

Regards,

Kirupasankar S,

India

[johnsold]

Many output devices "latch" the output when the value is written to the device. That value remains until another value is written. If the software shuts down without writing a zero value (or other safe value), then the last value written will remain until the device is unplugged or the computer power is shut down.

So, you, the programmer, are responsible for making sure that at the end of the program a zero value is written to the device. Using the event structure, it is possible to capture the exit or close window events and force the write before allowing the program to finish.

Lynn

[kirupacae@gmail.com]

Thanks Mr Lynn .,

[LV_Pro]

Many DAQ devices do not have a "default to zero" state. This means that when they are started they will come up in an unknown state, outputs on at unknown levels. Similarly, when you end a program that uses them, it should set the outputs to a desired output condition. They are devices that LabVIEW sends "messages" to, but unless you programmatically set their outputs at the program's conclusion most will continue to output the last value they received. This is also why a LabVIEW program should have a programmatic method of controlled shut down, rather than using the toolbar's "stop", as this immediately stops LabVIEW's execution, bypassing any code designed to perform an orderly shutdown.

[kirupacae@gmail.com]

Thanks