The What, Why & How of PLCs

Powder Automation: Programmable Logic Control Improving the efficiency of a pow- wiring. This soft wiring is a modifications in order to alter the der coating line is very important. program that simulates an electrical control of a component. Within a Those companies taking the time to circuit. A PLC consists of several PLC controlled system, the only investigate and implement new tools components: a CPU (Central change would be to the program and automation concepts will find Processing Unit) and I/O (Input/ stored in the memory. For example, their products being produced with a Output) modules. The I/O modules a typical relay has two to four superior looking finish while realiz- provide sensory input and then control contacts. The relay is limited ing improved performance in finish- controls output to the system in the amount of control or logic it ing line operationing costs. Many components. Examples of the types can perform. To expand the relay's users of powder equipment have of PLC inputs are push buttons, functionality, additional relays taken the time to evaluate new spray pressure switches, photo sensors, or would need to be added in parallel. gun, recovery booth technology and relay contacts. Now compared to a PLC program, a automation. Those that have in- "soft" relay can have hundreds of vested in these items realize many Example outputs can be indicator logical contacts and no additional benefits like improved film control, lights, relay coils, motor starters, wiring or component changes are reduced material usage, lower oper- while other types of devices that can required. ating costs and extended equipment life. Another key to improving system efficiency is to utilize automation. Automation includes the use of a programmable logic controller (or PLC) to operate gun controls, gun positioning, airflow controls, and other system variables. The use of PLC's is more popular with many users of new powder paint and powder systems. But a large portion of the industry is not using automated controls to improve upon the efficiency of their systems . There is real value in having powder guns turn on and off or the value of powder guns moving in and out. Many users don't understand these advantages and chose to ignore them. Example PLC Rack Configuration To help you better understand these be monitored and controlled are But to look at a PLC unit as a relay/ values, this booklet contains analog. Examples of these analog timer replacement is to miss a great valuable information about the use devices might be pressure sensors, deal of flexibility and customization of programmable logic controls in position transducers, temperature capability. powder coating systems. sensors, and variable speed motor drives. In most cases the equipment A PLC can: PLC Definition controlled in a hardwired system is 1. Handle complex information essentially the same as in a PLC 2. Perform advanced math A simplistic definition is that a PLC system. The difference is the functions is an industrial computer replacing flexibility that is afforded. A typical 3. Communicate with