Hi all, i wanted to aquire analog and digital signals from a NI 9174 cDAQ Chassis. There is one NI 9215 device for analog measurement and three NI 9401 for checking the over all 24 digital inputs. Now, i want to sample one analog channel and all digital lines synchronous. Only one NI9401 for digital and the analog card is not a problem, when configure the analog sample clock as sample clock source for digital in (picture). The problem is to have multiple NI9401 synchronized. I thought , I could change the channel name and extend the range, e.g. like this "cDAQ1Mod2/port0/line0:7, cDAQ1Mod3/port0/line0:7" but this creates an error message. Some other ideas, for example to use the DAQmx control task.vi and make the task 'reserved', didn't work. I know, it is possible to use a counter and create an own clock signal and provide it to the other NI9401 devices, but I don't want to renounce some digital inputs. I'm using LabVIEW 2013 (2017 is ordered and on the way) Thank you for your answers.

Ok, I have found the problem. Actually the error msg is not really useful, that is why it took some time 🙂 So it looks like, you must use the "one channel for each line" parameter for the "line grouping" input of the DAQmx Create Channel (DI - Digital Input).vi. If you use the "one channel for all lines" setting, you get error. I guess the reason is that, you cannot group together lines into one channel over several modules. If you need to use the "one channel for all lines" setting, just do what the previous poster suggested. Examples for both ways:

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LabVIEW, Synchronous measurement in cDAQ chassis

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Hi Blokk and jg69,

thanks a lot. Both solutions are working. What a small detail, I have overlooked.

Nice support!

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LabVIEW, Synchronous measurement in cDAQ chassis

Re: LabVIEW, Synchronous measurement in cDAQ chassis