New fine adjustment technique for heating process

This paper proposes controlling temperature in an oven by using integral-cycle binary rate modulation (ICBRM) method and AC line with frequency of 50 Hz. Microcontroller MCS-51 controls the binary rate multiplier (BRM) according to the proportional integral controller (PI) function. Discrete signals are used in the system modeled by using the Ziegler Nichols principle for analyzing the stability before designing the system. This procedure makes it easy to investigate system response. The system is implemented by an 8 bits digital circuit which gives 1024 patterns of AC signal for controlling the generation of energy for a 3000 watts thermal coil every 20 ms of each cycle. We divide scan time (Ts/sub n/) in to 4 intervals, 5 ms interval is selected to generate 256 patterns ICBRM. Because this method gives ripple lower than 2%, it generates less noise for the system. Moreover, we can consider the whole system from the time model of the control procedure and ICBRM algorithm of 40-200/spl deg/C with /spl plusmn/1/spl deg/C error in the 1 cubic meter oven.