Schweitzer Engineering Laboratories, Inc. (SEL) today announced new modules and protocols for its remote terminal unit (RTU) or programmable logic control (PLC) platform, the SEL-2240 Axion. Customers can now order low-voltage power supplies, four-slot backplanes, dual four-slot backplanes, and IEC 61850 GOOSE. The low-voltage power supply supports 24/48 Vdc sources. The pre-existing high-voltage power supplies support 125/250 Vdc or 120/240 Vac in the same unit. The four-slot and dual four-slot backplanes are useful for creating small distributed control systems. Both the Axion RTAC module and the SEL-3530 RTAC now support IEC 61850 GOOSE with up to 120 receive and 48 transmit messages, for greater flexibility in integrating a variety of intelligent electronic devices (IEDs).