IO Synchronization in FPGA module PXI-7833R

[Vkumar]

Dear all,

        I am using NI PXI FPGA module, PXI-7833R. Which is having 96 Digital IOs. In my application i want to synchronize all IOs, and generating PWM waveform with user diffined  phase difference. I tried to run each IO in separate while loop but it is creating synchnonization problem. Is there any way i can synchronize and generate PWM out put with phase shift.

--Vishnu

[StevenA]

put all of yor pwm generation code in the same loop so all the IO get written at the same time.  I would write a subvi like the image below then put as many instances of this in the loop as you need.  This example has phase control and a midpoint trigger (you may not need the trigger).

[Vkumar]

Dear Steven,

         Thanks for help. One thing i would like to know that, this will be like parallel loop only, Is it? As i understand  if we make subvi and use it in a single loop. It will work like parallel vi for each IO in a one parent loop.

         Second thing i want to know that this scheme, can i use for simple Digital IO cards?

Thanks

--Vishnu

[StevenA]

If you make this into a sub vi, set the vi properties to "reentrant execution".  Then make a copy for as many channels of PWM you need.  Then they will all run in parallel.  you can place them all in side of one loop.   Yes you can use a simple DIO module.  The only limitation of course is the speed of the DIO module. 

[Vkumar]

Thank you very much. Presently the system is in used. I will try this option and come to you again.

--Vishnu