SCXI Hardware Multiplexing

[India]

I am at present using SCXI-1100, SCXI-1102, SCXI-1126. I am planning to multiplex all these channels onto PCI-6071E DAS Board Channel 0. My Application is being developed using LabWindows/CVI. I have to acquire from each individual SCXI channels at the rate of 1000 samples/sec.

But I am unable to accomplish the same. In my program I am using Timer() function as I have turn on certain relays with reference to time. My application is very time critical and relevant data is available for 1 second only within which I have to acquire all of them & also do some control.

Kindly let me know how do the same using SCXI Hardware channel scanning. It would be appreciate if you can send me example demonstrating my requirement.

[shawn]

Hello Rajinikanth,

Thank you for contacting National Instruments. You should be able to achieve a sampling rate of 1000 samples/sec on each channel you are using with your hardware. I did find an example that you should be able to use as a template to start out. It is located at:
\daq\scxi\SCXI_SCANsingleBuf.prj

However, this example does use a buffer, which means that while you will be able to read at a very specific rate, there may be a delay between the time at which the value read at the SCXI module is actually processed in the computer. This means that if you are doing a control loop, it would be better to use a slower, non-timed acquisition with a simple control loop. If you have some sort of control loop, you should try to use the example:

\daq\scxi\SCXI_AIOnePt.prj
Notice, however, that with this example you will not get 1000 samples/sec.

I hope I have explained this well. If this doesn't help, you may want to contact National Instruments at www.ni.com/ask and explain the exact difficulties that prevent you from accomplishing this task.