Originally Posted by
MurphyWasRight
Since this was a refurbished unit it is possible that it was mis-assembled or damaged on installation/test, only other possibility is a wiring issue, which might fit with prior unit being intermittently bad. One can be sure the investigators will be looking at this in depth.
Does the system have protection against using data from a sensor with internal or wiring issues?
Safety related angular encoders used in other industries are having a dual architecture inside, the labeling of signals SIN,COS, and COM on an conceptual drawing could indicate this. (Two independent channels: one analogue, and one digital)
This does however not protect against a sensor with a frozen, or damaged mechanical vane from providing false data.