The Save statement allows you to specify the size of a buffer where the data will be held temporarily before being written to disk.
Note: Although a large buffer size where data is held before being written to disk reduces the time required for data logging by reducing the number of disk accesses, it is recommended that you do not configure large buffer sizes. The reasons are that: a) the data in a large buffer will be lost if there is a power failure; and, b) the memory used for the buffer is unavailable for other uses.
Data is recorded in files in a circular manner, meaning that once the pre-defined file size has been reached, the newest data replaces the oldest data in the file. Since the user controls the number of records in the file and the number of tags recorded in each record, the user determines the size of the files at the time of configuration. The time and date are automatically recorded with each entry in the file, as is the validity status of each value in the record.