Synchronization of multiple PXI 4461/PXI 4462 - AO and AI tasks

[meju97]

Hello everyone,

I’m having some trouble synchronizing multiple PXI boards. My setup includes two PXI-4461 boards and one PXI-4462. I’m using them to perform both analog output (AO) and analog input (AI) operations.

All boards are referenced to an external PCLK_100 clock, and I’m also using a Sync pulse to synchronize operations.

The problem I’m facing is with the AO: it should be triggered by an external trigger connected to the PFI0 pin of one PXI-4461 board. However, when I configure and run the AI tasks, the AO no longer responds to the external trigger. If I only run a simple example of continuous voltage output generation, the external trigger is detected and works correctly.

It is compatible to synchronize with Sync pulse the sample clocks and then use the PFI0 trigger to start the AO generation?

Currently, I’m starting all AI tasks first, and then (by manually starting another VI) I launch the AO tasks. Would be better to start all tasks in the same program?

Any suggestions would be very helpful.

Thanks!

Juan

[Kevin_Price]

I just posted a relevant remark about sync over here. 

I don't have personal experience with the 44xx series of devices to give detailed suggestions.  I can only say that I've done an awful lot of work on "pretty good" sync (10's to 100's of nanosec) and have almost never found it necessary to manually configure sync pulses and reference clocks.  Your approach *might* be overkill for your needs.

Tell us more about the level of sync you need and why.   Meanwhile, yes, you can almost certainly benefit by putting all the tasks into a single program.

-Kevin P

[santo_13]

Please read Dynamic Signal Acquisition (DSA) Synchronization Basics - NI

Please share your code for review.