The ELS300RX-NPN/DO-N is a safety relay module designed by Cedes. It provides an interface for a safety system to monitor and control industrial machinery. The module is a four-channel device that operates on 24VDC and has a voltage rating of 28VDC. It has two NPN outputs and two normally open (NO) outputs. Its features include a three-level switch, two optocouplers, a status LED, and a maximum switching frequency of 2kHz. The module includes a variety of protection mechanisms to ensure safe operation, including an overvoltage protector, a reverse polarity protection, and an undervoltage lockout. The ELS300RX-NPN/DO-N is suitable for applications such as safety gate monitoring, emergency stop systems, and machine movement detection.