A programmable logic controller or PLC is a type of digital computer which is used for automatic process of machineries. In short, PLC is used to make the machineries work automatically. There’re many areas, especially industrial ones, which use this PLC system. It’s different from the regular computer systems. The PLC is programmed to be able to respond to several inputs and produce several output responses. When industries or heavy machineries use this PLC system, the experts will make arrangements about the input and output commands, various ranges for the temperatures settings, resistance to impact and vibration features, and immunity to electrical noise and vibrations. The programs will be kept in the memory.
The Functions of Programmable Logic Controller
Nowadays, the use of programmable logic controller is used for motion control, sequential relay control, process control, networking, and distributed control system. There’s also the one system called as programmable logic relays, or the PLR, which is designed for small products. This is almost similar to PLC but it’s dedicated for light industries which produces small numbers of products. It doesn’t require a lot of cost and it only involves several points of incoming and outcoming signals.
Programmable Logic Controller Characteristics
Unlike the regular computers, the programmable logic controller has different characteristics, such as:
• It’s stronger than the regular computer and designed to withstand severe condition. It’s basically pretty strong against moisture, dust, cold, and heat.
• The basic system of PLC is that it has fixed connectors for input and output. When the base model doesn’t have enough I/O connectors, the expansion is possible.
• PLC still needs to interact with human for monitoring, programming, and observation. That’s why PLC will have HMI or Human Machine Interface, MMI or Man Machine Interface, and GUI or Graphic User Interface.
• PLC usually has built in ports for communication, such as Ethernet, Modbus, BACnet, DFI, RS-323 9-pin, or EIA 485.
• The writing process for PLC program is done in particular application on PC or laptop, and then downloaded through network or direct cable to the PLC.
Seeing that fact, PLC system has been proven to be very beneficial when it is used by everyone. Of course, having PLC system nowadays is very important because big mass production is impossible to do by manual process. Small scale industry is now able to use customized programmable logic controller to help them run their business.