Page 115 - Practical Control Engineering a Guide for Engineers, Managers, and Practitioners
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90 Chapter Four
10
5
>- 0
-5
-10
-15~~--~--~~~~--~--~~--~--~
o w w ~ ~ ~ ~ m ~ ~ ~
Ttme
FIGURE 4-13 Unbounded growth when phase lag is 180°.
I_~r ~~t:-:\ z :\ z 1
1
o 10 20 ~ ~ ~ ~ 70 ~ 90 100
1.--..--,~~--~--~~~--~--~~-.--~
FIGURE 4-14 Signal growth when process/controller provides -170° of
phase lag.
