An application of PLC´s as an RTU in SCADA systems

Pipeline operations use a master terminal unit (MTU) to acquire information from remote terminal units (RTUs). The ability to configure PLCs as RTUs or sub-MTUs provides capabilities for interfacing existing supervisory control and data acquisition (SCADA) systems. One inherent problem has been interfacing the PLC with different MTU protocols and interfacing the PLC with other devices at the remote site. The use of programmable C language-based communication modules eliminates both the use of hard-wired RTUs and the need to modify protocols. The use of C language-based communication modules for communicating between the MTU, PLC-based RTUs, and other remote devices that use various protocols is discussed