Safety relay category specialized for safety control of industrial robots and FA equipment. Complies with machine safety standards (ISO13849, IEC61508) and realizes safety functions such as emergency stop circuits, safety door monitoring, and light curtain interlocking. Features include redundancy through dual-channel structure, reliable operation with forcibly guided contacts, and high reliability supporting Category 3 and 4. Handles 2-channel safety relays, expansion safety relays, and safety relay units from manufacturers like Pilz, Omron, and Keyence. Essential control components for safety circuit construction in robot cells, automatic assembly equipment, and conveyor systems. Clearly distinguished from general-purpose relays and control relays with dedicated safety function design.