Peterbilt Motors Company, founded in 1939, is an American manufacturer of medium-and heavy-duty Class 5 through Class 8 trucks headquartered in Denton, Texas. Peterbilt operates manufacturing facilities in Denton, Texas (1980), and Sainte-Therese, ThÃ©rÃ¨se. quebec
A programmable logic controller, PLC, or programmable controller is a digital computer used for automation of typically industrial electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures.PLCs are used in many machines, in many industries.PLCs are designed for multiple arrangements of digital and analog inputs and outputs, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact.ore recently, PLCs are programmed using application software on personal computers, which now represent the logic in graphic form instead of character symbols. The computer is connected to the PLC through Ethernet, RS-232, RS-485, or RS-422 cabling.
Relays are used to isolate one voltage level from another. A PLC may be used to control the operation of a medium-voltage motor, perhaps 2,300V or 4,160V. A relay is used to energize the starter, which, in turn, switches the motor voltage while the PLC controls the relay.