Bumpless transfer
Bumpless transfer is switching AUTO/MANUAL without the output jumping. Without it the mode change is an upset, and the manual test that splits hunting from a disturbance becomes unusable.
What it means
Bumpless transfer means the controller initialises its internal state when the mode changes so that the output does not step. Without it, switching to automatic hands the process a sudden output change it did not need.
It matters for analysis as well as operation: if you cannot switch to manual and back cleanly, the manual test that separates loop-generated cycling from external disturbances becomes an upset in its own right.
Questions that come up
What is bumpless transfer?
The controller initialises its internal state on a mode change so the output does not step. Without it, switching to automatic hands the process a sudden output change it did not need.
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Glossary
Where this comes up
Written by PIDSnap control engineering. Published 2026-08-01, last reviewed 2026-10-22.