A comparison of protocol conversion methods for the retrofit of SCADA systems

SCADA (supervisory control and data acquisition) system retrofits present a problem not generally encountered in control system retrofits. Specifically, the problem is that the new RTUs (remote terminal units) generally use a different communications protocol than that used by the old RTUs and the central MTU (master terminal unit, or host computer), necessitating some form of protocol translation. The authors examine solutions to this problem. They describe methods for translation at the RTU, protocol conversion in MTU software, or translation using either a front-end processor or an MTU coprocessor. No solution is recommended generally