CHEN 4601 Study Guide - Midterm Guide: Kilowatt Hour, Minimum Phase, Long Term Ecological Research Network

• School: UMN
• Department: Chemical Engineering
• Course: CHEN 4601
• Professor: Prodromos Daoutidious

Document Summary

Ziegler-nichols/ continuous cycling method (most commercial controllers have this as built-in mode); Settings based on gain margin (for p, gm = 2, conservative) Pi: use lower kc to maintain about the same gm in face of i. Pid: slightly higher kc b/c phase leads b/c of derivative. How can we find kcu, pu? i) experimentally - on-line tuning technique. 11+ 2 : relay autotuning (astrom & hagglund); --> variant of ziegler-nichols; --> experiment where the controller is replaced by on-off controller (relay) Controller output = on-off like furnace; d vs. error signal; 2delta = dead time induced oscillation in output (w/ dead time at beginning: frequency response: angle gol( j c)= 180 c pu= 2 . |gol( j c)|=1 ku: direct substitution (closed-loop characteristic eqn) 1+gol(s)=1+gol( j c)=0, root locus diagrams, when the branches cross the asis; at j pu=2 . Step test technique/process reaction curve: break loop, record response.