Some questions about pxi-6040E

[tingyulou]

NI 6040E PCI, PXI 16 SE/8 DI 12 bits 500 kS/s ±0.05 to ±10 V 2 12 bits 1 MS/s ±10 V 8 2, 24-bit Analog, digital

here is the questions.

1. What is the difference between the "max sampling rate" and the "output rate"?

2.I have 5 signals with the frequency 8-10kHz to be obtained and select a segment in a cycle, then make some mathematic processings. To insure the accuracy, I have to get more than 300 points in my selection. We know that the "E series" DAQ card has only one AD converter shared by all channels. Then is 6040E fast enough for my request? If not, do I have to use a faster DAQ card such as "NI 6133"?

3.Can a "NI digitizer" be made as a role here? And what is the main differences between the "digitizers" and the "DAQ cards"?

[Otis]

1. The Max Output Rate refers to the Analog Output rate, which is different than the rate for the analog input. These are two distinct operation and one does not really affect the other.



2. Max sampling rate is going to be the fastest possible rate which you can sample. For one channel on the PCI-6040E the Max Sampling Rate is 500kS/s, if you are reading multiple channels then the Max Sampling Rate is 250kS/s (divided by the number of channels, so for 5 channels the PCI-6040E has a Max Sampling Rate per Channel of 50kS/s). Depending on the measurements you are trying to make this may or may not work for you. Typically if you want good data you want 10 S/period, and you are measuring a sample of up to 10kHz, so your ideal sampling rate would be 100kS/s per channel. However, if you are just wanting frequency information then you just need something faster than the Nyquist Rate, so this board should be able to handle that without a problem.
   
   The 6133 board can handle a rate of 2.5MHz, divide that by 5 channels and you should get a Max Sampling Rate per Channel of 500kS/s, that's 500 samples per period. The 6133 should give you much better measurements for the signals you are looking at.



3. I think you will be fine with a DAQ Card, the sampling rates are within the range you are looking at. Digitizers are essentially an excellent alternative to traditional benchtop instruments, they offer great precision and flexibility. I think the DAQ Card might be the better choice for your situation, but the added functionality of digitizers for making built in Time and Frequency Domain Measurements might be beneficial to you. For more info on digitizers look here: Why should I use High-Speed Digitizers?

[tingyulou]

appreciate your reply, Otis. OK, i will choose 6133

[thomson]

The 6133 has one A/D per channel. So you can sample up to 2.5 MS/s on each channel.

[Otis]

Thomson, thanks for pointing that out. I forgot the PXI-6133 is one of our Simultaneous Sampling boards. You can get the max rate on each channel if it's in parallel mode.