Ziegler-Nichols reaction curve recommended control constants
From Zeigler and Nichols
Type of controller | Kp | Kp/Ki | Kd/Kp |
P | AB | - | - |
P + I | 0.9 AB | 3.3 L | - |
P + I + D | 1.2 AB | 2 L | 0.5 L |
where A = M / O¥ and B = T / L based on the reaction curve test as illustrated below: