Multifunction DAQ

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Acquire and Log digital input

We are using a CDAQ9172 and some analog (NI9205) and digital (NI9411) input modules to log some signals on a laboratory model.


As we would like to evaluate the logged signals aftwerwards in a external tool, it would be the best to acquire all signals with the same sample rate.


Choosing continuous as sampling mode, logging is available for the analog signals only. Continuous acquired digital signals can't be logged (only acquired and displayed). Is there any possibility to log analog and digital signals who share a common sample rate?

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We are using Signal Express 3.0 on WinXP.

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Hi Healthcare,


unfortunately this is not a supported feature in a Configuration Programm like SignalExpress. But what you can do is to work with logging (Aufnahmemodus), there you can choose after you placed two steps running in parallel (AI (cont. Acq.) & DI (1 Sample)) to log the data trough the protocols (it´s a TDM-File on you directory, easy to open with other programs), from there you can easily see the data (parallel) in the Playback-Mode or to export the data directly with righclick to DIAdem or Excel.


The other second option is to implement a LabVIEW Step, but for this you need some experiences in creating a synchronized DAQ and implementing it as a SignalExpress Step. If you have a LabVIEW-Version check out the step and have a look at the examples.


Best regards


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Thank you for answering


I already did what you described before your answered.


Acquiring the digital and analog signal and viewing them in SignalExpress. It is right that they are displayed parallel. But when you export them, you get the following:

- For the analog signal you get (e.g.) 2000 measurement points over full measurement range

- For the digital signal you get (e.g.) 100 measurement points over full measurement range


This makes it difficult to compare them in a external tool. We would like to have the same number of measurement points over measuring time.


What is also a problem is, that we cant log the digital signal (counter0) faster than with 100ms sample rate. Is there any possibility to log this signal faster?

For explanation: We are acquiring a quadrature signal and evaluation it in cDAQ-Hardware with counter0. The value of counter0 is, what we require for further analysis.

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