How is data logging accomplished in PLC systems?

Data logging in PLC systems is primarily achieved by recording and sending data to a database. This method involves the automated collection of data from the PLC, which can include process variables, operational metrics, and performance statistics. The gathered data is then organized and transmitted to a database or a data historian for further analysis, monitoring, and reporting purposes.

This approach enables real-time or periodic tracking of system performance, facilitates trend analysis, and aids in making informed decisions based on historical data. The use of databases for data logging also allows for easier retrieval, manipulation, and visualization of the information, providing valuable insights for optimizing processes and troubleshooting issues.

In contrast, the other options do not effectively represent standard data logging methods in PLC systems. Manual input of data lacks the efficiency and accuracy provided by automated systems. Visual monitoring of outputs involves observation rather than data capture, and periodic reviews of operational status, while useful for assessing system health, do not constitute a systematic logging method.