I am attempting to select a temperature sensor for a controlled heating application. The sensor will need to be inserted into a chamber with a cartridge heater and steel ball bearings inside of some stainless steel tubing. I would like to meet the following specifications:
- Temperature control between 160.0 and 240.0°C
- Temperature accuracy of +/-1.0°C (in the above range)
- <250 ms thermal time constant for the temperature sensor
Everything I've read/calculated so far has led me to believe that I can accomplish what I would like to with a J or K-type thermocouple with appropriate cold junction compensation and correct thermal bonding inside the chamber while using a 12-bit ADC with signal conditioning mapping 0-4.5V to 140.0-260.0°C. Based on feedback the duty cycle of the cartridge heater will be adjusted. My questions are:
- Should I consider other types of sensors (have I overlooked something critical in my sensor selection)?
- What aspects of design will be the most critical to getting the most accurate possible temperature readings? (Guard rings, return current routing, etc.)