daniyal
Member
Dear All,
Its being very tough for me to control the cooling water temperature and vacuum by PID loop. attached is the control routine which i am using to control the temperature an Vacuum.
The system is consist of 8 cells of Cooling tower Fans in Power Plant that is operation by 8 PF755 VFD's by increasing and decreasing the speed of all drives at same time with PID controller to control the Elements.
Normally Vacuum Controller activated when the temperature is greater the Setpoint, and when the temperature is below down to the setpoint the control switches over to the temperature controller and decreasing the speeds to achieve the setpoint. But the fan speed decreases untill the temperature does not reached at the setpoint and it makes the oscillation for the drives. I have tuned the PID loop on very slow response to stable the speed at which temperature again rise but temperature goes down very rapidly.
Kindly tell me is there any better and accurate way for controlling or it need to be tune it again for nullify the oscillation and smooth the controlling.
Looking forward for your kind response
Thanks
Its being very tough for me to control the cooling water temperature and vacuum by PID loop. attached is the control routine which i am using to control the temperature an Vacuum.
The system is consist of 8 cells of Cooling tower Fans in Power Plant that is operation by 8 PF755 VFD's by increasing and decreasing the speed of all drives at same time with PID controller to control the Elements.
Normally Vacuum Controller activated when the temperature is greater the Setpoint, and when the temperature is below down to the setpoint the control switches over to the temperature controller and decreasing the speeds to achieve the setpoint. But the fan speed decreases untill the temperature does not reached at the setpoint and it makes the oscillation for the drives. I have tuned the PID loop on very slow response to stable the speed at which temperature again rise but temperature goes down very rapidly.
Kindly tell me is there any better and accurate way for controlling or it need to be tune it again for nullify the oscillation and smooth the controlling.
Looking forward for your kind response
Thanks