simultaneous sampling on 6071E

[marc lawrence]

Basically I am using a NI 6071 E (full spec DAQ card) to generate an analogue output (AO0 or AO1) - and this is being fed directly into AI0 and AI1. (The idea is to use the system as an impedance analyser for low frequencies < 100kHz).

At low frequencies (upto 50Hz) I can easily record the output signal - and get results similar to those seen on an attached oscilloscope. However at high frequencies I see purely a flat line which does not correspond to the resulting voltage.

I have tried various options using synchronisation of different read / write blocks, putting the system into different threads etc. However all to no avail.

Is there a silly mistake which I am making?

[Ryan_V[DE]]

Marc,

In order to synchronize AI and AO, they need to share a sample clock and/or one of them has to wait for the other to start (using triggering). While this is possible in Traditional DAQ, I would highly recommend switching to DAQmx. There is a LabVIEW example which does just this (sharing triggering). Please have a look at the "Multi-Function-Synch AI-AO" VI in the example finder.

Hope this helps,