I am trying to generate a sinewave analogue output with the USB-6009 and SignalExpress.I get an error message about the sampling time and setting on demand instead of continuous. What is the fix for this?

[Greenies]

 I am trying to generate a sinewave analogue output with the USB-6009 and SignalExpress.I get an error message about the sampling time and  the recommendation is to set on demand instead of continuous.This does not fix the problem Anybody with any ideas?

[DFGray]

The USB-6009 does not have clocked analog output.  It will set the output voltage when it is instructed by the calling software (SignalExpress in this case).  This is why you need to set the output to On Demand.  This means the time between your samples is set by SignalExpress, not the hardware, and is subject to any interruptions by the host operating system.  In addition, the maximum output rate is 150Hz.  If your sample period is less than 6.67ms, this will cause issues.  In any case, due to limitations of Windows, SignalExpress will have jitter in software timing on the order of 10ms - 20ms, and it could be a lot higher.  If these issues cause problems for your application, you will need better hardware with clocked analog output.

If you need more info, please ask.  If you would like us to look at your project, please post it.  If you want suggestions on a better piece of hardware, please give us more details on what you need to do so we can suggest something that will work for you.

[Greenies]

Thanks for the info. We have tried to generate a low frequency sinewave  at a sampling rate of 10ms but still without success. The sinewave signal refuses to copy into the DAQmx Generate analogue output box with the missing signal error. Is there something we need to set?

[DFGray]

Please post your project and what version of SignalExpress you are using so we can take a look.

[Greenies]

Thanks for your help but we have now changed to a USB-6259 board which works fine. We are now having problems generating digital signals from this board using SignalExpress. Do all the outputs require an exteral sample clock to work or is there someway round this?

[Greenies]

Thanks for your help but we have now changed to a USB-6259 board which works fine. We are now having problems generating digital signals from this board using SignalExpress. Do all the outputs require an exteral sample clock to work or is there someway round this?