Synchronization between two DAQs (NI USB-6008/6009)

[pblanos]

Hi to all,

I would be grateful if could assist me with the following issue I am facing, since I am not an experienced LabVIEW user.

I have put together two .VIs in the same LLB, the first one is a setup of an optoelectronic PPG sensor that detects pulse rate (this .vi was not created by me) and the second one is a thermistor attached to the optoelectronic sensor. Both configurations are connected to two DAQs, NI USB-6009 and NI USB-6008. The scope of this setup is to simultaneously record data from both sensors and compare them.

I have managed to record data from both sensors simultaneously with a global REC function. However, even though the two DAQs have the same  following Timing Settings,  when I record for a period of 10 seconds for example, the number of samples is not the same.

I am sending you attached the recorded files with data acquired from both DAQs and  also the two .VIs.

I would appreciate any suggestions and directions. If any more information is needed please let me know.

Thank you in advance.

Panos

[TomMcQ]

Hi Panos,

It would be good to understand what level of synchronisation you're looking for. The devices you have (6008 and 6009) are software timed and cannot be 'synchronised'. However, if you're looking for samples to be collected at 'near-enough the same time' (within a couple of milliseconds), then you can do that by adding both DAQ tasks to the DAQ Assistant.

I hope this helps.