Advantages: 1.Small physical size & shorter project time. 2.Cost effective for controlling complex system. 3.Reliability. 4.Less and simple wiring. 5.Faster response. 6.Remote control capability. 7.More flexibility. 8.Ease of maintenance / troubleshooting. Disadvantages: 1.Fixed circuit operation. 2.PLCs manufacturers offer only closed loop architecture. 3.PLCs are propitiatory, which means software and parts one manufacturer can’t be easily used in combination with part of another manufacturer. 4.Number of optional modules must be added to maximize flexibility and performance.