Data Acquisition for Pressure and Angle

[Fird]

Hi ALL.

I read some of the post regarding one project.

http://forums.ni.com/ni/board/message?board.id=170&thread.id=212334&view=by_date_ascending&page=1 

I would like to get some ideas from this. 

I would like to acquire a data of pressure and also angle from engine. Pressure sensor and angle encoder are used.

However, how to decide or how to design the VI so that the DAQmx will only require the data of pressure during the first trigger of angle encoder. Instead of that, how to know that the the angle encoder already 720 degree so that I would say it is already one cycle of pressure that I would like to acquire.

I would be appreciated if anybody could assist me.  

Thanks.

-Fird- 

[Fird]

Hi ALL, 
 
I already designed the VI to acquire data of pressure from the sensor.
 
Please take a look on figure below:

Basically, what I did 

i. Acquire Signal from Dev1 which is USB 6009

ii. Using a sample clock. 

       - from PFI0

       - active edge

       - determine the samples per channel from continuous samples

iii. Write the data - for 1 channel Nsample 

       - i make the number of samples per channel is the same for sample clock to make it synchronize. is it a good way to do that? 

       - i make it in a loop as i consider the number, N as a Number of cycles (each cycles contain of N samples)

My curiousy is that, how do I want to stop the acquisition when the sample clock from PFI0 already reach third rising edge. Because, the acquisition start when there is an active rising edge. For the first two of rising edge is consider as 720 degree. And when it reaches third rising edge, I want to consider that the first cycle is done.

- Fird -  

[Fird]

Hi ALL, 

I changed my design as shown in the figure below.

I'm using USB 6009 for this project. As for the time being, the Source of Start Digital Edge i use is OnboardClock. While Source of Clock and Source of Analog Input Pressure is connected to the PFIO and AI0 respectively using signal generator (TTL output and sinusoidal graph respectively).

However, the error message shows :

------------------------------------ 

Possible reason(s):

Source terminal to be routed could not be found on the device.

Make sure the terminal name is valid for the specified device. Refer to Measurement & Automation Explorer for valid terminal names.

Property: Start.DigEdge.Src

Property: Start.DigEdge.Edge

Source Device: Dev1

Source Terminal: OnboardClock

Task Name: _unnamedTask<58>

--------------------------------------- 

I hope someone could assist me on this.

Thanks.

p/s - Hoping someone to reply this tread.

-Fird-