Hello,
I am a graduate student in process control field. I want to control
batch process using PID controller.

I want to apply PID on batch system to make it follow certain
trajectory of controlled variable. In PID, based on the error Ysp -
Ymeasured, I am calculating required change in manipulated variable,
deltaU. [e.g for P only controller, deltaU = Kc*(Ysp - Ymeasured)]

My problem is how to calculate actual value of manipulated variable to plant. In continuous process case, we can add this deltaU to steady state value of manipulated variable. (e.g.: if at steady state %opening of valve is 30% and calculated deltaU is 10% then we make actual opening = 30% + 10%). But in batch process we don't have any steady state so I don't know How to calculate actual input to plant.

Please help me. If you have some good reading material please send me the link. Thank you very much

Rahul Gandhi

PS: I don't know to define batch process mathematically. These are the processes, which don't have steady state. Its model varies with the value of state. In linear case, it can be defined as dx/dt A(x).x(t) + B(x) u(t). Example of batch process is batch type fed batch reactor.

I want to apply PID on batch system to make it follow certain

My problem is how to calculate actual value of manipulated variable to plant. In continuous process case, we can add this deltaU to steady state value of manipulated variable. (e.g.: if at steady state %opening of valve is 30% and calculated deltaU is 10% then we make actual opening = 30% + 10%). But in batch process we don't have any steady state so I don't know How to calculate actual input to plant.

Please help me. If you have some good reading material please send me the link. Thank you very much

Rahul Gandhi

PS: I don't know to define batch process mathematically. These are the processes, which don't have steady state. Its model varies with the value of state. In linear case, it can be defined as dx/dt A(x).x(t) + B(x) u(t). Example of batch process is batch type fed batch reactor.