HC900 Hybrid controller. firmware versions later than v4.4 support an historical data collection function. The Trend A display in which changes in value over time of one or more point parameters are presented in a graphical manner. See also: display, point parameter. Point function blocks added to the controller Also known as remote terminal unit, RTU. A generic term for a device that is used to control and monitor one or more processes in field equipment. The most common control and monitoring device in an access control and security system is an access control panel. Other devices include security monitoring panels, elevator controllers, and fire monitoring devices. Controllers include programmable logic controllers (PLCs), loop controllers, bar code readers, and scientific analyzers. See also: C200 controller, control processor, CPM, hybrid controller, network node controller, PLC. configuration allow the controller to buffer point values that are collected at configurable rates.
When this function is configured in the controller, the buffered data can be used to populate history on the Experion server The computer on which the Experion database software and server utilities run. See also: Experion server TPS. if a controller is disconnected from the server and cannot collect point values via normal scanning. The process used is called history backfill and is initiated when the controller comes back online after it has been disconnected for more than one minute. This disconnection could be due to:
- the controller failing due to a communications failure
- the controller being diabled (Out of service)
The history backfill function only supports standard history The type of history that collects one-minute snapshots of point parameter values, as well as a number of averages based on those one-minute snapshots. Compare: exception history, extended history, fast history. See also: history, point parameter. 1 minute snapshots for analog and status points. When history is backfilled, value/timestamp pairs are read from all configured trend buffers in the controller. These are then inserted into standard history snapshots as if they were read by the server at the value's timestamp.
The history backfill function is a licensable option.
- Standard history averages are NOT re-averaged
- .Any Status point A type of standard point that is used to represent discrete or digital field values. See also: dual-bit status point, standard point. PV The process variable. An actual value in a process. In the case of an analog point, for example, the PV represents values such as temperature, flow, and pressure. A PV may also be sourced from another parameter or be calculated from two or more measured or calculated variables using a point algorithm. See also: analog point, parameter, point algorithm, PV algorithm, PV clamp, PV period. or OP with non-consecutive addressed bits is not recalculated