I would suggest that if you are looking at taking temperature sensor data and attempting to control some type of heating/cooling device that you implement a PID loop for stability. https://www.crossco.com/blog/basics-tuning-pid-loops Many simplistic approaches use an ON-OFF controller to turn on cooling or heaters. These can make your stability problems worse than if you just wrapped things up in an insulating blanket. You end up cycling from one extreme to the next. PID loops when properly tuned will vary the speed, current or duty cycle as the temperature approaches a set-point. This avoids overshoot and gives much finer control over the temperature. We used to use 4 wire platinum probes to measure temperature down to the hundredth of a degree. Then for control of the heater element we had a PWM (pulse width modulated) supply. Once the loop was tuned (to minimize positive feedback that causes increasingly crazy oscillations in temperature while at the same time settling in once the temperature soaked through the mass) we could hold a set-point through some wild external temperature extremes. There are software implementations of PID (Proportional, Integral, Derivative) that are pretty easy to understand. There are also surplus temperature controllers on eBay that can accomplish the same thing. *Ms. Tisha Hayes, AA4HA*

I will comment on a couple postings: On Wed, Apr 4, 2018 at 8:00 PM, Tisha Hayes <tisha.hayes@gmail.com> wrote: > > I would suggest that if you are looking at taking temperature sensor data > and attempting to control some type of heating/cooling device that you > implement a PID loop for stability. I have implemented a PID controller with PWM output for a Peltier Cooler for what is basically an oven to test TCXO boards. Performance is pretty good, holding the temperature to within tenths of a degree. I tend to connect sensors or sensor boards to an Arduino and output data to and take commands from the serial port. The Arduino does the "real time" stuff and the fancier stuff is implemented on a PC. On Thu, Apr 5, 2018 at 6:20 AM, Bob kb8tq <kb8tq@n1k.org> wrote: >Hi > >If you want something that is pre-calibrated, then the IC based parts are the way to go. I have used thermocouples with MAX31855 thermocouple interface boards and also have used DS18B20s, which are quite interesting "IC" parts. You can connect several in parallel, and they use the "One Wire" protocol, easy to implement, saving wires. The problem with them is there are lots of counterfeits out there. I bought them from a random supplier and they did not work correctly. I contacted the manufacturer and they confirmed they never made any with the date code that was printed on them. I bought some from Digikey and they looked different and worked fine. Luckily I was able to return the bad ones. Regards, Mark W7MLG