AO.MaxRate, AO.MinRate, AO.Voltage.rngs properties for USB-6008 DAQ device

[GabrielaK]

Hello,

in one of my VIs I use the AO.Voltage.Rngs property to find out if the selected DAQ board supports the voltage range that the application needs. This works fine for my PCMCIA card and also for a PCI board. Now, running the same VI with a USB-6008 device, this property does not give any values back. Also, the properties AO.max.rate and AO.min.rate report "0", the output error is -200197. I am using DAQmx as it is supposed to support the same functions for all DAQmx devices. Can somebody please tell me what is wrong here and how I can get around this?

Best regards,

Gabs

[GabrielaK]

It's getting more and more crazy. I have tried to delete this property node, as the AO.MaxRate and AO.MinRate properties were obviously the problem. NOW - I get more and more errors. DAQmx StartTrigger (None) reports Error -200452, DAQmx Timing (Use Waveform) reports Error -200077 and claims that I have chosen Sample Clock as Sample Timing Type (but I have chosen "Use Waveform") and I should use OnDemand, which is not available in this frame.

The problem is, this VI is not an application, it is a driver VI which is supposed to work with all NI DAQ devices supported by DAQmx. How can I solve these problems with the USB-6008?

Best regards,

Gabs

[MarkGrot · Accepted solution]

AO.min.rate and AO.max.rate are returning 0 and error -200197 because the USB-6008 does not support hardware timed analog output.  The description for that error is "Device does not support this property."  There is a knowledge base entry for this issue.

Selecting "Use Waveform" uses Sample Clock timing.  The waveform data type specifies a delta t which is used to set the sample clock rate.  This is not supported on the USB-6008.  You should either not set your sample timing type or explicitly set it to "On Demand".

The DAQmx driver supports hundreds of different devices.  Not all combinations of properties are valid for all devices.

[GabrielaK]

Thank you, Mark, this explains the errors.

Regards,

Gabs