how to use DAQmxGetAIConvMaxRate

[DaytonaEd]

Driver: NI-DAQmx 7.5.0

Visual C++ 6.0

PCI-6220, PCI-6221, USB-6009, etc.

My problem is that I need to measure all channels as quickly as possible at each sample, in other works to get close to simultaeous sampling of multiple channels but using a multiplexed card.  I understand how to set the vaule using DAQmxSetAIConvRate, but as we are using a wider variety of cards I want the driver to tell me what this value is - sounds easy.

I have read on the forum about DAQmxGetAIConvMaxRate but it doesn't show up in my C Reference Help, so I can't find the parameter list.  So to avoid guessing, can someone help please???  I would expect this value to be 250k for a PCI-6220, or 48k for a USB-6009 - is that correct?

Ed

[AlanArmstead]

Hello DaytonaEd,
I'm not sure why that function isn't in your DAQmx C Reference Help.  I have the same version of NI-DAQ, and I got to that function by clicking on the Contents tab, then expanding NI-DAQmx C Properties and clicking on "List of Timing Properties".  The function was listed (in the right window) under More>>AI Convert.  Anyway, the max convert clock rate is usually equal to the max sampling rate of the device.  This is true for you M Series devices, PCI-622x family, and it can be set with the function you mentioned:  DAQmxSetAIConvRate.  However, the USB-600x devices do not have the ability to set the convert clock rate.  Its convert clock rate is always chosen by the driver.  You can, however, use the DAQmxGetAIConvRate to query the rate.
-Alan A.

[DaytonaEd]

Found it, not sure how I overlooked it before.  Thanks for the help.

Ed