Hi
I have to raise the temperature over a fixed time (plant steam in coil) ...and then hold it at temperature and the cool (cooling water in same coil)
So it is something like...Heat to 80C over 25 minutes, hold at 80+/-1 then cool to 30C over 1 hour
My question is the ramping... I am thinking of simply calculating the PID Setpoint over time, so it ramps up..The PLC is a Siemens S7-300 type and I usually use FB41 for PID control
For the cooling I am thinking of opening the valve slightly for the first x seconds because I am concerned the process may damage the hot coil
Cheers
I have to raise the temperature over a fixed time (plant steam in coil) ...and then hold it at temperature and the cool (cooling water in same coil)
So it is something like...Heat to 80C over 25 minutes, hold at 80+/-1 then cool to 30C over 1 hour
My question is the ramping... I am thinking of simply calculating the PID Setpoint over time, so it ramps up..The PLC is a Siemens S7-300 type and I usually use FB41 for PID control
For the cooling I am thinking of opening the valve slightly for the first x seconds because I am concerned the process may damage the hot coil
Cheers