Controlling of Peltier Caliberator

Perhaps you can find a manual or similar circuit.

Is your PID controller using feedback (i.e thermocouple)?

Is you peltier device matched to your power supply?

What is the make and modle of the devices you are using?

Sorry to ask more questions than you did but you gave so little information.

What do you mean by control? Do you mean you cannot regulate the temperature to maintain the accuracy or stability at the setpoint(s) you require or that it just doesn't work at all.

Please provide more information, including a description of your application, temperatures, primary use, etc. If it were me personally and this is for calibrating thermocouples or thermometers I would use an oil and ice bath as this is standard in the temperature calibration industry. Peltier devices are....difficult to work with.

_{Jack - former Testing Laboratory Technician}