DAQmx, SCXI and Maximum Rate

[rmnnad]

My system configuration is PCI-6220 and 4 SCXI-1100 modules installed inSCXI-1000.

My task is to port VB application from NI-DAQ to DAQmx.

In order to provide the new application the same scan rate capabilities(usually all 128 channels should be scanned at maximum rate (166000 Hz) whileaccuracy restrictions are not important) as the old one I'm looking for the wayto eliminate the MaxRate values provided by DAQmx. 

As I understand there is a solution by using the DAQmxSetAIConvRate function. 

At the same time there is only one function there the sample mode can beprovide for the DAQmx - the DAQmxCfgSampClkTiming function.

In this function I should use the DAQmx_Val_FiniteSamps parameter.

That is the correct procedures order for my case?

I have tested  

DAQmxCfgSampClkTiming...

DAQmxSetAIConvRate ...

with rate 1200Hz (1296Hz max for 166000HZ per 128 chans) but the error was generated "Maximum rate was exceed"...  

[GarPar]

rmnnad-

You are right that you want to use the DAQmxSetAIConvRate function. However, instead of 1200, use 166000Hz for the maximum rate for all channels. This information is documented in KnowledgeBase 4XK8KIMK: Why Won't the SCXI-1100 Sample Faster Than 100k S/s?, linked below. It explains how to use the DAQmxSetAIConvRate function in LabVIEW, but the same principle applies in VB.

http://digital.ni.com/public.nsf/allkb/3C9B7125D9F798D3862575BD005071CB?OpenDocument

Best of luck with your application!

Regards,

Gary Parente
Applications Engineer
National Instruments