With its ability to directly switch 24 and 125 VDC loads as well as 250 VAC loads, the One Series ST can provide SIL 2-certified control for final control elements such as pilot valves, actuators and motor controllers, without involving a DCS or safety PLC. The ability to directly control legacy equipment that utilizes 125 VDC control schemes is especially valuable to power plants. A process sensor, logic solver and safety relay are embedded in a single, SIL 2-certified field device. Although the device looks like a traditional temperature or pressure transmitter, it can switch final elements such as valves, motors, and blowers directly from the transmitter.
United Electric Controls