[Ether]

You can get some fault detection even with a single sensor by doing range and rate sanity checking.

Examples:

1) You know a pot should be reading between 90 and 120 degrees, but it returns a reading of 10 or 200 degrees.

2) You are supplying power to a motorized subsytem and it should be moving but the position (or speed) sensor says that it is not.


Increasingly, "smart actuators" are being used on automobiles. These actuators have a tiny microcontroller to control and monitor the actuator's performance and report trouble codes via the CAN bus.