Hans,
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By a "freeze," I do mean where the control loop is not executing for multiple reasons.? This can be a situation where the MPU is waiting for an interrupt that does not occur.? ?In my control experience (PLC, NOT MPU), The way to address this was to make the critical interrupt routine as simple as possible to reduce this type of failure.? ?Most PLCs implement a program check routine that is the highest priority interrupt.? It takes much of the processor to check, and I believe it can be as high as 20%.? This is to verify that no code changes have occurred and that the time between heartbeats is not exceeded.? Maybe it's overkill for this situation.
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73
Evan
AC9TU
