DO/AO sync signals not working when changing port/line of DO

[Nidhogg]

Hello!

I'm a novice and I'm using a PCI 6251. I can't understand why this DO/AO VI only works when the DO line is set to port0/line0.

I have 4 lasers TTL connected to different ports (and diff channels) 0.0, 1.2, 1.3, 2.4, and a galvo control on the AO, moved buy a sawtooth waveform (points in the "output array"). I want the laser to be on when the ramp is rising and off when it's falling. I have an array of 1/0 values to be fed to the DO. Both arrays have the same number of samples.

For some reason I can't understand, the VI only works when the DO is on port0/line0, while when connected to the other lines doesn't.

Any suggestions on the reasons this is happening?

I was following this example:  https://forums.ni.com/t5/Example-Code/Synchronizing-Analog-Output-and-Digital-Output-Signals-Using/t...

[ZYOng]

NI 6251 only supports digital waveform on Port 0. You need to assign all 4 TTL channels to P0.

From NI 6251 Device Specifications

[Nidhogg]

Hello and thank you for your reply!

I also tried to move one laser to P0.1, but it didn't work 😞

[ZYOng · Accepted solution]

Did you test only one line at a time or assign P0.1 to another task while P0.0 is still running?

You cannot have more than one hardware-timed digital input task. You need to assign all P0.0 to P0.3 to a single task using NI-DAQmx Syntax for Specifying Physical Channel Strings

[Nidhogg · Accepted solution]

Thank you! I think I fixed it now!!!!