Dear Sir/Madam,
I have got an M-Series NI6251high-speed multifunction DAQ system operating with Labview 7.1 using Windows XP on a 3GHz Pentium 4 PC with 1GB RAM.
This system has been succesfully used for approximately 2 and a half years now for relatively low-frequency applications.
The card specifications say that I should be able to sample up to 8 Channels at a 10 MHz sampling rate. The reality is though that I can only achieve approximately 1.3 MHz when scanning a single channel, 550KHz when scanning two channels, and approximately 200KHz when 3 channels are connected. If higher frequencies are used, the Labview software gives an error message that: The Analogue to Digital converter was attempting to convert a new value before it had finished with the last reading.
As a result of this I have to choose respectively low sampling frequencies, which do not allow me to capture the higher frequencies which I need to acquire.
A second problem is that I am seeing some significant 'ghosting' of the first channel on the other scanned channels. I have found some documentation on this on your website, and I will try to solve this problem using this documentation first, but may get back to you if I cannot solve this problem with the help of these.
Could you please let me know if you have ideas for the possible causes for the first problem (low sampling frequencies), and possibly suggest some solutions to this problem. Your help would be much appreciated.
Yours faithfully,
Alessandro
