Synchronize digital and analog output on NI PCIe-6251 / BNC-2110

Hi,

I am using two analog ouputs on BNC-2110 (NI PCIe-6251) for controlling a galvo-scanner (x- and y-axis) and one digital output for controlling the exposure start of my CMOS-camera. When I start them consecutively in my script (see example code), there are huge timing jitters in the execution time of the start dqCamTrigger command (in the order of milliseconds, which changes the phase relation in each execution). Is there any good way to synchronize both the digital and analog output so they have a constant phase relation? Here is the relevant code I extracted from my program:

d = daqlist;

d{1, "DeviceInfo"}

dqScanner = daq("ni");

dqCamTrigger = daq("ni");

[ch1, ixd1] = addoutput(dqScanner, "Dev1", "ao0", "Voltage");

[ch2, ixd2] = addoutput(dqScanner, "Dev1", "ao1", "Voltage");

ch3 = addoutput(dqCamTrigger, "Dev1", "ctr0", "PulseGeneration");

SVoltArray = [1 0 0 0 0 0

0 0 0 0 0 0 ]' %just an example array

dqScanner.Rate = SampleRate*1000;

dqCamTrigger.Rate = SampleRate*1000;

ch3.Frequency = 1/((LineTime)/1000);

ch3.DutyCycle = 0.25;

preload(dqScanner, SVoltArray);

start(dqCamTrigger, 'Continuous');

start(dqScanner, 'RepeatOutput');

Thank you for your help :)

Answer 1

[Patrick Byers]

Hi all,

I solved the problem myself and post it here in case somebody else needs a solution for this. I just assigned the digital output to the data acquisition interface "dqScanner". When starting the dqScanner interface, both digital and analog output channels are started with synchronization (without any additional command).

[ch1, ixd1] = addoutput(dqScanner, "PXI1Slot2", "ao0", "Voltage");

[ch2, ixd2] = addoutput(dqScanner, "PXI1Slot2", "ao1", "Voltage");

ch3 = addoutput(dqScanner, "PXI1Slot2", "ctr0", "PulseGeneration");

SVoltArray = ...

preload(dqScanner, SVoltArray);

start(dqScanner, 'RepeatOutput');