From OpenSCADAWiki
When archiving messages, they are passed through a filter that works according to importance level and category of messages. Messages level in a filter indicates that you must skip messages with specified or higher levels of importance. For filtering by category, templates or regular expressions are used to determine which messages to pass. Each archiver has its own filter settings, therefore, it is easy to create various specialized archivers for the archive of messages. For example, archivers of messages can be directed to:
- logs, to store debugging information and other working information of servers;
- different protocols (users action protocol, protocol of violations and exceptions, messages protocol ...).