Control System & Fail Safe System in Parallel

[andrewjoe777]

Hey yall,

So I have a control system that regulates the current sent to a proportional valve based off of the position of the rocker arm I am trying to move. I also have a failsafe system that reads the state of the system and if those states have surpassed certain thresholds, the system goes into a safe state. 

Now, I'm having problems trying to figure out how to make these things run in parallel. I want the control system constantly delivering input currents to the valve while simultaneously monitoring the outputs and if the outputs are past the threshold, it stops the control system and puts the spool in the valve back to the center position. Anyone know how I should go about this?

[nathand]

Where is LabVIEW in this problem? When you say "in parallel" - are these two portions of the same program, or two separate pieces of hardware (for example, a dedicated-purpose fail safe, and a computer as the control system), or something else? If it's just two functions of the same program, perhaps you can elaborate on the problem you're facing and share some code. Depending on how your code is structured there are lots of options. For example, maybe you have one loop that handles the fail-safe function and is also responsible for setting the output value. It could normally read the output value from a notifier or other storage that can be shared between loops, but when the fail-safe condition occurs, it ignores that value and sets the safe output value instead.