| Experion HS R530.1 User Assistance

# Operational aspects of history backfill

CAUTION: For points that have history backfill configured:

- 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. 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

A history backfill will be initiated for a 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. when any of the following events occur:

- If the controller has been in the 'Failed' or 'Marginal' state for more than 1 minute and hen returns to the OK state. History backfill needs to be enabled as well.

- If the controller has been Disabled (Out of Service) for more than 1 minute and is then enabled (In service) and returns to the OK state. History backfill needs to be anebled as well.

- If the controller is in the OK state and history backfill has been disabled for more than 1 minute and is then re-enabled.

ATTENTION: History samples will only be backfilled if they have not been collected by the Server The computer on which the Experion database software and server utilities run. See also: Experion server TPS. by normal scanning.

## Timestamps

If a 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. Rate function block Also known as FB. An executable software object that performs a specific task, such as measurement or control, with inputs and outputs that connect to other entities in a standard way. They can be connected and grouped together to construct simple or complex control strategies. You can view function blocks as a symbol, configuration form, as part of a strategy, or as a user-defined view in an operator schematic. See also: function block configuration form, function block faceplate, function block symbol. has been configured in the controller, up to three buffers are allocated in the controller to store the data that is collected. Each of these buffers has two timestamps; one to indicate the oldest sample it stores and another to indicate the most recent sample it stores.

These timestamps can be viewed on the Controller Status display for the HC900 Hybrid controller. controller. These timestamps are only updated when the controller is enabled (In Service).

## Alarms and events

When a history backfill occurs an event is raised to indicate the controller that was backfilled. If any missed samples are detected (that is, neither the controller nor the server collected the samples) an alarm An indication (visual and/or audible) that alerts an operator at a Station of an abnormal or critical condition. Each alarm has a type and a priority. Alarms can be assigned either to individual points or for system-wide conditions, such as a controller communications failure. Alarms can be viewed on a Station display and included in reports. Experion classifies alarms into the following types: - PV Limit - Unreasonable High and Unreasonable Low - Control Failure - External Change. is raised indicating the controller, the point and the time period when samples were missed.