Monthly Tech-Tip | No tracking! No ads! |
If you are aware of devices not listed here please contact us. We want to focus on those in active development. Devices supplied on manufactured kilns are usually relabelled, they are not actually made by the kiln manufacturer.
These are all very inexpensive and easily available.
When the prototype is working we will incorporate the software into a ready-made, battery-powered device that uses this same controller chip. It is likely that the display will not be needed for logging operations, the device will simply watch for temperature rise and automatically begin recording when that happens.
The 220V enters lower left to a terminal block. That splits to a transformer (above) and relays (below that). The 4-07-6024 transformer supplies power to the SMT_3140 controller board (converting the 220V down to that needed by the circuit board). The controller is run by an MSP430 Texas Instruments microcontroller (lower left closeup). That controller has inputs from the thermocouple and a current monitor (yellow donut shape around the wires going to the elements). The board has outputs that connect to the relay, that relay in turn controls the flow of current to the elements. This is a simple device, but not something to be replaced lightly. DIY controller boards documented online look tempting but they are not CSA or UL approved (so fire insurance coverage is implicated). Commercial controllers focus on safety and liability over functionality, they handle intermittent thermocouple connections, bad thermocouple readings, stuck relays and shorted and weak elements - these are runaway conditions that could become meltdowns in a kiln controlled by a DIY device. This being said, these commercial products do have a weakness: The relays. They are mechanical devices and are the first thing to need replacement. Kiln controllers thus need To be good at recognizing relay failure.