"Performance" of Simulated Devices

[mepausle]

Hello all,
I did not have access to my DAQ hardware today, so I experimented with using Simulated DAQMX devices. I built a simulated device and plopped a DAQ assistant down into a blank VI and set it to continuously acquire a voltage at 1kHz. I set the number of samples (i.e. buffer) to 100 samples. I put this inside a For Loop (10 iterations) and plumbed the DAQ assistant to a TDM storage file. After running the VI, the file indeed shows 1 second of "captured" data, which I interpret as 10 pulls from the buffer. However the code ran considerably longer than 1 second (ballpark 5s-10s)
So my question(s) is this : Do I have fundamental misunderstanding of how to properly use the DAQ assistant? Would this have run quicker on my actual DAQ rig (M-series installed in a RT Target) instead of a sim'd device?

Thanks in advance for humoring a newbie...

Matthew
Mech. Engineering Dept.
NC State University

[chrisger · Accepted solution]

hi there

i just created a VI like you described it and tested it with my real and a simulated device. the real device took about 1000ms for 10 x 100 Samples @ 1000 Hz. The simulated device ran about 25 times FASTER than the real device, though the acquisition settings are the same...

so i wouldn't trust that much in the timing behaviour of simulated devices (to be honest, i think that wouldn't be a easy job to simulate the timing in all cases...)

[PiMaster]

I'm getting similar performance from some VIs I'm running today.  The while loop is set to run every 5 msec.  I have a display counting up seconds.  It seems to be running long (I can count seconds myself and get a higher number than this display).  I would think that it was wrong, except that my PID Setpoint Profile generator is changing setpoints exactly on schedule.

Maybe the counter in my head done be broked. 

Go Pack!