... how OSSD outputs work?
OSSD means "Output Switching Signal Device". This output type is typically used with safety sensors and safety light curtains or for safe control outputs. Conventional 24 V DC outputs are actually critical for safety functions, as they cannot be detected by an external 24 V line via a short circuit. For this reason, the two OSSD outputs are switched off with a time delay. During the pause time of the output, a built-in input is activated and read back. If 24 V is present at the input after switching off the output, an error is detected and the two built-in processors safely switch off both outputs. This technology makes it easy to monitor short circuits and cross circuits up to PLe according to EN ISO 13849-1. With the aid of an extended LED diagnosis, such as on the HOLDX R process guard locking or the RFID safety sensors of the SAFIX, the detected faults on the safety sensor can be quickly detected and make troubleshooting considerably easier.
Time course of input and output functions