Residual voltage on ao channel

[Nemesiss5]

Hi there.
How can I remove the residual voltage on my Ao voltage channel?
I'm using the DAQ assistant to generate a voltage to my motor. When the vi stops running, I expect the channel to also stop generating the voltage.
However, it appears that the voltage still remains on the channel.
How can I remove this residual voltage on the channel?
Thanks.

Regards,
CP

[johnsold]

After the loop exits, write a zero to the AO line before stopping your VI. Or arrange the logic so that when the loop is about to stop, the last write sets the voltage to zero. The DAQ device does not know what you want or when you have stopped, so you need to explicitly do that last write.

Lynn

[Nemesiss5]

thanks for the help lynn. appreciate it 🙂

[Jcwire]

Hey, could you explain more in detail how to do that? Im having the same trouble.
Thanks

[johnsold]

What part did you not understand?  Detaile, specific questions get better answers.

One brute force method is to place another DAQ Write with a value of zero as the last thing which executes before clearing the task.  Depending on the architecture of your program there may be more effective ways.

Please be specific about what you have tried, what is working, waht is not working, and what actually happens with the part which is not working.  Other people will not have your hardware, so posting your VI with typical data saved as default is helpful.

Lynn

[Jcwire]

Im having the same problem as in that my DAQ still has residual voltage after i press the stop button on my labview program( its attached). Im trying to control a 3 phase motor using a Yaskawa G7 drive. The only way for me to stop the motor is to set the voltage to 0 but i want the stop button to do that. If you could explain me how to do that id really appreciate it or if you could provide with a sample VI even better since Im not that experienced in the terminology when it comes to labview. Thanks for your quick respose.

[johnsold]

You need to send a zero voltage to the motor drive after the loop stops.  The easiest way to do that might be to place another copy of the Voltage Generator Express VI after the loop.  Wire the error out from the loop to the error in of the VI and then pass the error out from the VI to the Error Handler. Wire a zero constant to the data input of the Voltage Generator.

I dont have DAQmx so I cannot easily modify your VI for you.

Lynn

[billko]

At the least, consider using an event structure.

Better yet is to consider an event driven state machine.

[Jcwire]

Thanks for you help lynn. It worked