I have two identical thermistors. I will refer to them as sensor A and sensor B. Sensor A reports the vessel temp. while sensor B monitors the output of the heater. The original heater had just a 2 degree temperature differential. The new heater that must be used produces a temperature rise of 8 degrees F. on sensor B. What I am trying to do is automatically modify sensor B to read no more than 2 degrees hotter at any time than sensor A, using A as a reference through it's temp. range.
An example of the resistance readings at two ends of the temperature range for this project is as follows: At 59F tank temperature sensor A is 48,840, heater is putting out 67 degrees so sensor B is about 40,000, difference of 8840. At 104F sensor A is reading 16,149 and sensor B is 112F @ 13,500 a difference of just 2,650. So I need a clever way to add 8000 ohms or so when colder and gradually reduce using A as my reference as temp. climbs to finally just 2500 when warmer.
Thank you in advance for your suggestions.
An example of the resistance readings at two ends of the temperature range for this project is as follows: At 59F tank temperature sensor A is 48,840, heater is putting out 67 degrees so sensor B is about 40,000, difference of 8840. At 104F sensor A is reading 16,149 and sensor B is 112F @ 13,500 a difference of just 2,650. So I need a clever way to add 8000 ohms or so when colder and gradually reduce using A as my reference as temp. climbs to finally just 2500 when warmer.
Thank you in advance for your suggestions.