Specifications

Glossary

Glossary - 10

The main point parameters are process variable (PV), output (OP), set point (SP), and

mode (MD).

PlantScape can store and manage multiple values in the one point. You can therefore

use a single point to monitor and control a complete loop. In many cases, however, the

only parameters of a point that need to be configured are:

• The PV which shows the current value of a given location within a controller, and

• An OP used to reset or control a point

The names of the parameters reflect their most common usage. They can, however, be

used to hold any controller values.

periodic scan

A defined regular interval in which the server acquires information from the controller

and processes the value as a point parameter. The scan period must be defined in Quick

Builder for each point source parameter value.

Plant Information Network

PLC

See Programmable logic controller.

point

A data structure in the server database, usually containing information about a field

entity. A point can contain one or more parameters. A point is classified by type: status,

analog, or accumulator.

PlantScape uses different point types to represent a range of different field values. The

point types themselves can be of either a flexible or fixed structure depending on the

type of controller they are associated with. Flexible structure points are used for the

Honeywell Hybrid Controller and fixed structure points are used with all other

controllers.

The fixed point types are:

•Status

•Analog

• Accumulator

point algorithm

A prescribed set of well-defined rules used to enhance a point’s functionality. The point

algorithm accomplishes this by operating on the point data either before or after normal

point processing.

plscpcg.book Page 10 Monday, May 28, 2001 10:11 AM