parallel control and measurement of different pressure signals

[Joshua_Chang]

Hi, everyone,

I just got a question about how to parallel the control and measurement. I am using PCI-MIO-16E-4 and PCI 6602, NI Labview 8.5. 

The process works like following:

Basically, this is an engine combustion measurement. The measured signal is incylinder pressure, while the controlled signal is fuel pressure. The ideal goal is like: the fuel pressure is controlled by a PID subVI, while the pressure is measured independently with this PID control. Because these two tasks use different rate, different modes (triggured vs continuous), and different AIAO (incylinder pressure only AI vs. fuel pressure AIAO), I currently did not come up with a strucuture that can bring them together. 

I can realize them separately, but no idea about how to integrate them. Does anyone give some suggestion on how to get this done? Like what kind of structure I need to use to realize this? 

Thanks a lot!

[Brandon_B]

Hello Joshua,

I'm not really sure how you would like to integrate these tasks if they are going to be running at different sampling rates and configurations.  You can use the same start trigger for all the tasks, but other than that it just depends on what you would like to do (i.e. event every N samples etc.).  What I can tell you though is that that the 6602 is a digital card and will not be able to perform any analog generation or acquisition.  Also, the PCI-6040E (PCI-MIO-16E-4) only has one analog input timing engine, which means that all analog input tasks on that card will have to run at the same rate.  There are tricks to run at a faster rate and then just average your samples as to make it appear that you are running at a slower rate, but that will have to be determined once you figure out the rates you would like to run.  I hope this helps.

Regards,