I'm not an electrical expert and lately, I ran into a problem using PWM for steady control of a heating rod.
Let's assume there is a set value (Temp in C) for the heating rod. I'm currently using a PID controller to output certain % at the end of the PID loop. This valve is used to feed to the PWM to generate necessary PWM signals.
The problem is once the actual temperature almost reaches the range of set temperature. The switching ON/OFF occurs very often in order to keep to the Set temperature.
Moe often switching causes to reduce the lifetime of the hardware. And replacement of hardware is out of option. Hence, I'm forced to think of an alternative logic for better control of the temperature.
The 2-point controller is something easier however, it is observed that there are a lot of deviations from the setpoint.
P.S: There is a delay of 5 seconds between two switches (some hardware related restrictions). Hence the turning ON of Turning OFF pulse can't be less than 5 seconds.
I really appreciate your ideas or suggestions on some simple strategy where I can reduce the number of switching and at the same time have better control over the temperature.
Is it a trade-off one has to choose between better control and less switching(in the end lifetime of switches)?