Project ForgeInstrumentation & Process Control
Controller Modes
GATE 2013
Hard
For the computation of Ziegler-Nichols settings (for Gp(s)=5/(2s+1)⁴), the ultimate period (in s/cycle) and the ultimate gain are
- Aπ and 0.8, respectively
- 4π and 0.8, respectively
- C4π and 1.25, respectively
- Dπ and 1.25, respectively
Explanation
At the crossover frequency ωco=0.5 rad/s: |Gp(jωco)|=5/(1+(2×0.5)²)²=5/4=1.25. Ultimate gain Kcu=1/|Gp|=1/1.25=0.8. Ultimate period Pu=2π/ωco=2π/0.5=4π.
Source: GATE CH 2013 (2013)
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