You could have some moving element with limit switches and an encoder, that’s pretty common. There’s probably others…
Normally the limit switch would be reliable but it will degrade over time, could be damaged in use, be assembled wrong etc… and the encoder might not be very accurate from the get go.
So if you want a safe/reliable system under as many conditions as possible you might get a problem space like this
Normally the limit switch would be reliable but it will degrade over time, could be damaged in use, be assembled wrong etc… and the encoder might not be very accurate from the get go.
So if you want a safe/reliable system under as many conditions as possible you might get a problem space like this