Using temperature controllers and micro PLCs to speed small-scale automation projects
Figure 1: Power switching options for industrial heater control. (Image source: Omron)
control (Figure 1). Each of those techniques presents a different set of performance characteristics: ■ Phase control provides the best controllability response with good solution size and cost, plus acceptable noise performance for most applications. ■ Cycle control provides good controllability response, solution size and cost, and excellent noise performance. In “optimum” cycle control, the switching status is determined for every half-cycle. ■ On/off control using solid state relays (SSRs) provides good controllability response with the smallest solution size, reasonable cost, and excellent noise performance.
From curing materials like thermo-set resins and adhesives to producing food and beverage products, industrial processes often require temperature control to maintain efficiency and ensure quality. Industrial heaters are necessary, but temperature controllers are the key. There’s more than one way to control the temperature of industrial heaters. The system's operating priorities determine the approach selected. Simple voltage control can be used when operating costs are the primary consideration and less precise temperature control is tolerable. By regulating the voltage powering the heating element, the power consumption of the
heater can be controlled, and the heat output can vary. Changes in voltage can be implemented quickly, producing corresponding temperature changes, but with a lag that varies with system design. Reducing the voltage will reduce energy costs and lower the temperature. Still, the reaction time for temperature reductions can be too long for many processes, and it can be difficult to control the temperature precisely. Beyond basic voltage control For many applications, basic voltage control is inadequate. In those cases, designers can use on/off control, cycle control, optimum cycle control, or phase
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