Assigning different sample rates in single session (session-based interface)

Hi,

I am writing code to output and input some signals using the session based interface in Matlab. My configuration is as follows:

Data acquisition session using National Instruments hardware:
   No data queued.  Will run at 1000 scans/second.
   Number of channels: 4
      index Type Device Channel   MeasurementType         Range        Name
      ----- ---- ------ ------- ------------------- ------------------ ----
      1     ao   Dev2   ao0     Voltage (SingleEnd) -10 to +10 Volts
      2     ai   Dev1   ai0     Voltage (SingleEnd) -1.0 to +1.0 Volts
      3     ai   Dev2   ai1     Voltage (Diff)      -5.0 to +5.0 Volts
      4     ai   Dev2   ai2     Voltage (Diff)      -10 to +10 Volts

Dev1 has a max sampling rate of 2 MS/s while Dev2 is at 250 kS/s. I would like to be able to run no.1 at 100 kS/S, no. 2 at 2 MS/s, no. 3 at 100 kS/s and no.4 at 100 kS/s.

When I create a session object and add all the above channels to it, I can only set a global rate that applies to all devices and channels in that session. I would like to assign sampling rates separately.

My thoughts on that are the following: Is it possible to create different session objects (so that I can assign individual sampling rates) and then execute startForeground() for each one of them? Note that I want the channels to be synchronized with each other. My existing trigger is as follows:

AO_AI1.addTriggerConnection('Dev1/PXI_Trig0','Dev2/PXI_Trig0','StartTrigger');

Thank you so much for your time. I will be looking forward to your replies!

Kind regards, Orpheus

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/24757-daq-session-based-input-is-it-possible-to-have-different-clocks-for-input-and-output