• A binary log records binary changes-of-state, meaning active (on) or inactive off. Binary logs are typically configured to record upon each state change. • An integer log records integer values, such as number of heat stages active Integer logs are very similar to analog logs. • A multi-state log records the output of a “multi-state object that is, an object with more than two discrete states. A speed fan is an example, having discrete states of off slow med and fast Multi-state logs are typically configured to record upon each new state change. • A string log records string (text) values, and is used for special-purpose applications. A string log is the only log type that cannot display graphically. Each log holds its most recent records in its own log buffer, stored in the station that the log resides. A log’s buffer size (limit) is configurable, but many logs have the default buffer size of 60 records. Most logs are configured with a rotating buffer which means that after reaching the buffer limit, the oldest record (sample) becomes overwritten to make room for the newest record. The alternative configuration fora log is to stop when full.” A BOUT A RCHIVES One of the main functions of a Web Supervisor is to provide continuous storage of data for logs, otherwise known as archives. Archived log data is typically pushed from logs to a large SQL application database in the Web Supervisor. Each archive can store many thousands of records fora log, from its oldest (first record) to its most recent (at least up to the point of its last archive. Refer to Chapter 7, Application Database for more information. Log data maybe archived manually (archive command. More typically, log data is archived automatically once a day, and/or upon reaching a near full buffer condition. C HARTS VS . T ABLES The default view for most logs (string logs excepted) is the log chart view.
