Hysteresis
Hysteresis is a different valve position for the same signal depending on whether it was approached from above or below. On a plant it is used with deadband and backlash for the same lost motion.
What it means
Hysteresis means the valve ends up in a different place for the same input signal depending on whether that signal was rising or falling. Plot commanded position against actual position and it appears as a loop rather than a line.
In practice hysteresis, deadband and backlash are used loosely and often interchangeably on a plant. The distinctions matter less than the consequence, which is the same in every case: the controller cannot place the valve accurately, and the loop cycles.
Questions that come up
What is hysteresis vs deadband on a valve?
Hysteresis is a different position for the same signal depending on direction. Deadband is a range of signal that moves nothing. On a plant both mean lost motion the controller cannot place.
Related
Where this comes up
Written by PIDSnap control engineering. Published 2026-08-01, last reviewed 2026-10-22.