Possible output rates using the PCI-MIO-16E-1 (PCI-6070) card

[the basher]

Hi,
In my VI (am using the LabView 7.0) I built a function generator which produces a signal with a specific frequency and this signal is put out using the DAQ assistant. I configured the output rate of the DAQ assistant for the analog output task with 1000Hz. It worked without a problem but the measurement was a bit slow, so i turned the rate up to 10000Hz. Well the measurement gets faster but the DAQ assistant multiplies the signal frequency with factor 10!! For example instead of a 50Hz signal (which i adjusted) I get a 500Hz one, and so on. What's the problem?? The Data sheet of the PCI-6070 card shows that an output rate of max. 1MS/s is possible! Where is the problem? Please help me!

[Ingo_Schumacher]

Hello,

this behaviour is absolutely normal. Signal generation and signal output rate are related to each other. An easy calculation example will explain what I mean. Generate a sine wave with, say 100 points per per period, and put this wave into a buffer. The analog output functions are accessing this buffer. Now think of programming an output with the update rate of 100 Samples/s - you will be able to output 1 period of the sinewave in a second - that will make the frequency of the signal 1Hz. If you use an update rate of 1000S/s you will need onle 1/10th of the time to generate a whole sinewave - this makes your signal 10Hz.

Increase the number of points in your signal generator in the same amount as you increase the update rate and the generated signal will be of the same frequency (but better resolution).

Hope this helps