asrock70
Full Member level 4
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I built a high-temperature furnace, the first layer of Promaform insulation with a resistance of 1430 C, heating elements Kanthal wire A1 max 1400C. Installed power approx. 3 x 3000W. I am currently making heating elements.
Temperature measurement inside 2x Type K thermocouples, with 19 bit ADC.
Use, primarily for baking molds for precision casting, temperatures up to 1000C, but a precise increase in temperature must be observed, for example 150C/hour or hold a certain temperature for x hours.
Secondary, melting of copper and aluminum alloys, temperatures up to 1100C.
I'm secretly hoping that it could manage to heat gray cast iron to a casting temperature of 1300C, I really don't know if that's realistic.
I'm starting to figure out how to control it, whether it will be some kind of STM32 or ESP32 or something like Raspberry Pi. It's purely about the interface with the environment, in terms of performance, x52 would be enough.
If I calculate correctly, the output per second at full power and one phase is 3kJ/s, with three then 9kJ/k.
If the request is for a maximum temperature increase of 150 C, it is 0.0416667 per second, the resolution of temperature measurement with a 19-bit ADC is 0.0078125, i.e. 5.3 LSB, with a temperature increase of 100 C/h, it would be 3.5 LSB.
My idea of driving.
The operator will enter something like
1h 150C
1h 150C
1h 400C
3h 400C
2h 900C
3h 900C
Meaning, increase the temperature to 150 C in an hour, keep it at 150 C for another hour, then increase the temperature to 400 C in an hour, etc.
Does the idea of controlling temperature 18C increase to 150C per hour ie. deltaT/s = 0.036666 C/s i.e. 5 LSB rounded. If rise <= next second heating On, otherwise Off.
Is it a very bad idea, or is there a more sophisticated way, something like PID, but also monitoring the rate of temperature rise, not just the target temperature?
Temperature measurement inside 2x Type K thermocouples, with 19 bit ADC.
Use, primarily for baking molds for precision casting, temperatures up to 1000C, but a precise increase in temperature must be observed, for example 150C/hour or hold a certain temperature for x hours.
Secondary, melting of copper and aluminum alloys, temperatures up to 1100C.
I'm secretly hoping that it could manage to heat gray cast iron to a casting temperature of 1300C, I really don't know if that's realistic.
I'm starting to figure out how to control it, whether it will be some kind of STM32 or ESP32 or something like Raspberry Pi. It's purely about the interface with the environment, in terms of performance, x52 would be enough.
If I calculate correctly, the output per second at full power and one phase is 3kJ/s, with three then 9kJ/k.
If the request is for a maximum temperature increase of 150 C, it is 0.0416667 per second, the resolution of temperature measurement with a 19-bit ADC is 0.0078125, i.e. 5.3 LSB, with a temperature increase of 100 C/h, it would be 3.5 LSB.
My idea of driving.
The operator will enter something like
1h 150C
1h 150C
1h 400C
3h 400C
2h 900C
3h 900C
Meaning, increase the temperature to 150 C in an hour, keep it at 150 C for another hour, then increase the temperature to 400 C in an hour, etc.
Does the idea of controlling temperature 18C increase to 150C per hour ie. deltaT/s = 0.036666 C/s i.e. 5 LSB rounded. If rise <= next second heating On, otherwise Off.
Is it a very bad idea, or is there a more sophisticated way, something like PID, but also monitoring the rate of temperature rise, not just the target temperature?