We were requested to make a heater controller for an existing silicone heating device. The heating element was a Nickel-Chromium resistance wire placed between two layers of silicone impregnated glass cloth. Silicone heating board rating was 96W and it had a 24V, 5A Power Transformer.
The requirements included the followings:
- Smooth controlling the heat of the board between 40o – 80oC.
- Working with 24Vdc supply
- Having proper protection
There are a variety of options for temperature controllers for silicone heaters. Each type of temperature controller is typically installed right into the silicone heater:
Since virtually any type of temperature controller can be incorporated onto the heaters, for this request, an MCU design was considered. Some of the main components of the design included the followings:
- A PIC Microcontroller (PIC16F1823)
- 3-Digit, 7-segment LED Display (JS3-2832Bx)
- PTC Resettable Fuse
- Tactile Switch with 5mm height (DTSM-62x-x-V)
The PIC Microcontroller was responsible for controlling the PTC temperature and the changes of temperature were set by the tactile switch and the firmware of the MCU.
For making the final design, it took about three months to design, make the prototype, write the firmware and test it. The final product was according to the given requirements.