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June, 2018


PLC Security Critical to Today’s Automated Factories


By Joseph Zulick, MRO Electric and Supply Company, Inc. P


LCs (programmable logic con- trollers) are user-friendly micro - processor-based specialty com-


puters that carry out control func- tions, many of which have high levels of complexity. As security concerns grow around factory automation, get- ting up to speed with the different types of PLC security is crucial. Companies should develop pro-


tocols for security breaches so that employees can react quickly and effectively. Training before a security breach occurs is even more impor- tant. Workers should understand the different types of control systems in their manufacturing environments and which ones are the most suscep- tible to security issues. Programmable logic controllers,


Companies should develop protocols for security


breaches so that employees can react quickly and effectively. Training before a security breach occurs is even more important.


also known as PLCs, initially came about in the late 1960s. PLCs were designed to replace relay-based machine control systems in the major


PLCs are an excellent replacement for relay-based machine control systems, but are vulnerable to hacking and exploitation.


were disliked by those in the automa- tion and manufacturing industries. In 1968, Dick Morley of Bedford


Associates designed the Modular Digital Controller, later dubbed the Modicon. After the Modicon 084’s introduction, there was no looking back to relay-based control systems. Today’s PLCs are engineered to


Usually used in industrial electro- mechanics, PLCs deal with the con- trolling of machinery, such as factory assembly lines, power stations, dis- tribution systems, power generation systems, and gas turbines. PLCs are programmed using a


computer language. Written on a computer, the program is then down-


U.S. vehicle manufacturing space. The relay-based control systems were considered difficult to use and


endure harsh and strenuous condi- tions, such as those in heated, cooled and even moist environments.


loaded to the PLC through a cable. These programs are then stored in the PLCs memory. The hardwired logic is exchanged for the program fed by its user during the transition between relay controls to PLC. The manufacturing and process control industries have taken advantage of PLC applications-oriented software since the Modicon.


Functions and Directions PLCs use programmable memo-


ry to store particular functions and directions. These include on/off con- trol, timing, sequencing, counting, arithmetic, and data manipulation. Different types of PLCs can be organ- ized into three general categories. Advanced PLCs offer the greatest processing power, with larger memo- ry capacities, high I/O expandability and many networking options. A compact controller is an intermedi- ate-level offering with an increased set of instructions and more I/O options than a run-of-the-mill logic controller. Basic logic controllers are often referred to as “smart relays.” These are straightforward to use and are a good place to start when consid- ering PLCs. Basic logic controllers are a cost-effective option for low-I/O, slower-speed applications.


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