I'm trying to heat a fluid to a certain temperature (under 100C) using nichrome wire, with a thermistor measuring the temperature of the fluid to allow controlling the nichrome wire using PWM and a PID controller. However, it is absolutely necessary that the nichrome wire itself remain below 150C or so. I could just test different PWM values and cap the PID output to a value that never reaches the maximum temperature, but then initial heating from room temperature will be slower. Is there any other way I can achieve this?
How to quickly heat something to a given temperature with nichrome wire, while keeping the wire itself under a given maximum temperature
heatpid controllerpwmthermistor
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Best Answer
What you are trying to do is usually achieved with two (2) temperature sensors.
One sensor is in the fluid. It has a good thermal contact with the fluid, but no direct contact with the heater.
It's used by the control loop to hold the setpoint.
The second sensor is on the heater itself. It has a direct contact with the heater. Ideally, it would be buried inside of the heater.
This sensor is used to monitor for overheat.