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**OPTIMUM PID CALCULATION
FOR NON-SELF REGULATING (NSR) PROCESS**

based on Zieglar-Nichols
formulation

**1. The Fundamental**

**2. Example using data
captured using a paperless recorder**

2. Process rate = (80% - 60%)/(32.4 s - 12.8 s) = 1.0204 % / s

3. Step input = MV2 - MV1 = 64.9% - 40.5% = 24.4%

4. RR = process rate / step input = 1.0204 / 24.4 = 0.04182 / s

5. Mode = PI : P = 111.1 x 0.04182 x 2.6 = 12.1% , I = 3.33 x 2.6 = 9 s

**3. Example using data
captured using a chart recorder**

1. Td = 3.6 s

2. Process rate = (68% -
52%) / 21.6 s = 0.7407 % / s

3. Step input = MV2 - MV1
= 44.3% - 25.9% = 18.4%

4. RR = process rate / step
input = 0.7407 / 18.4 = 0.04026 / s

5. Mode = PI :
P = 111.1 x 0.04026 x 3.6 = 16.1% , I = 3.33 x 3.6 =
12 s

**TEST
YOUR SELF**: Can you calculate the optimum PI for this process