angelbein
Newbie level 4
pwm heater
The machine that we are designing is controlled by a Visual Basic program. The main goal of the machine is to achieve the graph of the Temperature over time according to the Ramping rate inputted by the user.
The graph of the ramping rate is linear while the graph of the temperature suddenly increased at the beginning of process.
We already made the circuit of the machine. We used LM35 and ADC0808 for the sensor inputs connected to the parallel port. We also used optoisolator and triac to control the temperature for its ON/OFF process. But how do we actually control the sudden increase of the temperature to follow the ramping rate?
Actually the PWM that we used is slower than ordinary PWM. In 1 second, the ON/OFF states follow the duty cycle of the PWM, for example, 10% duty cycle means that in 1 second, the ON period is 10% or 100 milliseconds and 90% ms OFF.
Will it have an effect to the heating process if we control the heater by PWM?
The machine that we are designing is controlled by a Visual Basic program. The main goal of the machine is to achieve the graph of the Temperature over time according to the Ramping rate inputted by the user.
The graph of the ramping rate is linear while the graph of the temperature suddenly increased at the beginning of process.
We already made the circuit of the machine. We used LM35 and ADC0808 for the sensor inputs connected to the parallel port. We also used optoisolator and triac to control the temperature for its ON/OFF process. But how do we actually control the sudden increase of the temperature to follow the ramping rate?
Actually the PWM that we used is slower than ordinary PWM. In 1 second, the ON/OFF states follow the duty cycle of the PWM, for example, 10% duty cycle means that in 1 second, the ON period is 10% or 100 milliseconds and 90% ms OFF.
Will it have an effect to the heating process if we control the heater by PWM?