A Tag group (formerly scan class) dictates how often an Ignition Tag will get new values (poll) from the PLC. A Tag group can be set to any rate you want. Generally a Tag group will run every second, or something similar. There are several modes available, and ways to make changes to the poll rate on the fly. You can learn more about Tag groups here.
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. It is the successor to the Secure Socket Layer (SSL) security protocol.