How to synch cdaq measurements from different modules?

[querty999]

A novice wants to know if there's a way to synchronize input readings from separate cdaq modules.

I have a voltage measurement on a NI9219 analog input channel and a frequency measurement from a NI9211.  Appears to me that a "task" can contain input signals from only one module. Is this correct or is there a better way?

Buffered input seems to be essentially useless when multiple tasks are employed. I'm thinking the only way to get synchronized readings is to read each channel individually inside a loop. But this seems to restrict the program to low speed data acquisition with unevenly spaced measurements. Is this correct?

My goal is to create a data file with three columns: time, voltage, frequency. What's the best way to get these readings at the same instant?

Referrence to a help document or tutorial would be great.

thanks! 

[HeatherBaker]

Hi,

You can include channels from multiple C Series devices in a task and NI-DAQmx automatically synchronizes the devices.  All channels in the task must be of the same I/O type.  In the DAQmx Help file (location described below), expand "NI-DAQmx Device Considerations", then "Multi-Device Tasks", and select "C Series".  This will elaborate on the requirements.  As a side note, the NI 9211 is a thermocouple module, thus a frequency measurement will not be possible.  Hopefully this helps!    

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