Loop-Role Tuning Advisor: objective-first PID tuning for refinery level and dead-time loops

A DCS add-on that classifies each control loop's operational role — tight regulation, averaging (surge-smoothing), or dead-time-dominated — from the auto-tuner's own test data, then tunes to that objective instead of the default minimum-error setting. It fixes the common failure where surge-drum level loops are tuned tightly and pass disturbances downstream instead of absorbing them.