Abstract
Conventional cam operated temperature programmers do not provide precise temperature control during programmes. An ideal choice will be to use proportional action during programmes to keep the deviations within a degree centigrade. The paper deals with a method using two feedback loops, one of them acts as a fast loop modulating one-tenth of the total power, thereby keeping the deviations less, the other acting as a slow loop, to keep the power control linear. The design also incorporates different rates for rise time and fall time and proportional control during soak time.