OSR stands for which PLC concept?

• A. Output Status Register
• B. One Shot Rising
• C. Offset Sample Rate
• D. Operational Scan Repeat

Answer: (B)

Edge-detection that yields a single pulse per transition. One Shot Rising is an instruction used in many PLCs to monitor an input and emit a short, one-scan pulse when the input changes from off to on. This means you trigger something exactly once on the rising edge, regardless of how long the input stays active. The pulse duration aligns with the PLC scan cycle, so it won’t keep retriggering while the input remains high. This is ideal for initiating actions like starting a device or logging an event only once per activation. Other options describe different concepts—tracking output status, a sampling-rate offset, or a different type of scan behavior—none of which capture the single-edge, one-shot pulse behavior that the rising-edge detector provides.