Read RT status on fpga

[Lewis_G]

I'm using a sbRIO 9636 to build a fixed wing UAV.  The FPGA is just doing PWM I/O.  It Reads PWM from the RC receiver and outputs PWM to the servos to control the flaps.  This is working fine:

And the RT:

As you can see, the servos can only be controlled from the RT.  I would like to be able to check the status of the RT OS from the FPGA and if needed, use a local variable on the FPGA to set the PWM output of throttle based on the PWM input (just a simple pass through).

To explain further, if the RT OS crashed, the fpga would realize and then control the servos based on what the receivers are saying.  so if the RT OS crashed, the fpga could run on its own.

I was thinking I could just have a loop on RT and keep checking the i terminal to make sure it is incrementing but I was wondering if there was a better way?

Hope that makes sense and thanks.

Lewis

[T-REX$]

Hey Lewis,

Have you thought about using a watchdog architecture, as found in the fail-safe reference design for compactRIO? You can also use the "System Reset" IO Node found in your chassis IO folder to reset the RT Controller when it fails to pet the watchdog (can't remember if the reference design does this).