A data logger can record live sensor values.

• A. It streams data only at startup
• B. It cannot log sensor values
• C. It replaces the PCM
• D. It records live sensor data for analysis

Answer: (D)

A data logger is built to capture measurements from sensors over time and store them for later analysis. The best description is that it records live sensor data for analysis, because it continuously samples values and saves them with timestamps so you can review how things behaved later. While some loggers can display data in real time, their primary purpose is creating a historical record for investigation and validation. It doesn’t just stream data at startup, it doesn’t mean it cannot log values, and it doesn’t replace the PCM—the data logger is a separate device used for monitoring and recording data.