NIDAQ digital out timing/grouping

Support
1

Hi Chris,

Quick question. I want to use MWorks to run an MEG experiment downstairs. The MEG computer has 16 TTL input channels that are used to receive event codes from the experimental computer. In the words of Dimitrios Pantazis, the scientist in charge of the MEG setup, “Just make sure the onset happens simultaneously in all BNC wires.” I’m assuming that if MWorks assigns multiple channels in succession it will be in effect “simultaneous,” but I just want to check what you think about that. There’s no “word out” function, is there? Should I get clarification from Dimitrios about how simultaneous “simultaneous” has to be?

Thanks,
Evan

2

Hi Evan,

NIDAQ digital output channels do support word output (as requested by Seth in your lab), and that’s definitely what you want to use, as I doubt that setting channels one by one would be “simultaneous enough”. The issue is that, as currently implemented, the word size is limited to the number of lines in a port, which is typically eight for the devices supported by NI-DAQmx Base.

If you need a 16-bit word, then MWorks will need to configure multiple ports in to a single output channel. I believe this is possible, but it will require some changes to the NIDAQ interface plugin. When would you need this by?

Chris

3

Great! I tracked down Seth’s post and found your example file. As of now I don’t need more than 8 bits so I should be good to go.

Thanks,
Evan