D - H

data link

A directional link between controllers across which variable bindings data is conveyed.

database

The collection of definitions making up a project. The version control feature stores checked-in information in a separate database.

DATE

The format of a date is year-month-day, separated by hyphens. Basic data type that can be used to define a variable, a parameter or a controller.

de-energize to action

An output circuit for a Safety Instrumented Function where the field device is usually energized. Removing the power deactivates the device.

debug information

Log data which tracks results of stepping between program organization units and called functions Useful when troubleshooting a runtime program by simulating the step-by-step execution mode.

debugging

Also known as simulating, the process of detecting defects in a project that includes setting and clear breakpoint, step-by-step debugging, and cycle-to-cycle debugging.

declared array

A user-defined array defined as a data type.

declared instance

A function block having assigned instances that are declared in the dictionary. Declared instances of function blocks can be added to a program organization unit during online changes.

defined word

Word that is an expression. This word can be used in program organization units. At compiling time the word is replaced by the expression. A defined word cannot include another defined word.

dependency

A state in which one object requires another object to perform an operation , such as data variables in a program or functions within a library.

design mode

An editing mode during which the application is not connected to the runtime module.

dimension

The size (number of elements) of an array. For example: [1..3,1..10] - represents a two-dimensional array containing a total of 30 elements.

directly represented variable

A variable is generally declared before its use in one program organization unit. Inputs and outputs can be used without any declaration respecting a defined syntax. It corresponds to direct represented variables. Example: %QX1.6, %ID8.2

discrepancy

A condition existing when one or more elements disagree.

DINT

An atomic data type consisting of a DWORD used to store a 32-bit signed integer value (-2,147,483,648 to +2,147,483,647).

DWORD

Unsigned double word 32-bit format. Basic data type that can be used to define a variable, a parameter or a controller.

duplex module

A processor or one I/O module belonging to a pair of modules arranged in a parallel configuration. The parallel arrangement enables two paths for command signals and I/O data and increases their fault tolerance.

dynamic behavior

Continuous and sequential execution of the steps and operations of a program during an execution cycle.

energize to action

An output circuit for a Safety Instrumented Function where the field device is usually de-energized. Applying power activates the field device.

ETCP

A network driver that uses the TCP / IP stack.

Eurocard I/O Module

A Eurocard I/O Module is a Eurocard sized Printed Circuit Board (PCB) without a casing. The I/O module is available with or without a front panel.

execution control initial state (EC initial state)

The execution control state that is active upon initialization of an execution control chart.

execution control state (EC state)

The situation in which the behavior of a basic function block with respect to its variables is determined by the algorithms associated with a specified set of execution control actions.

execution control transition (EC transition)

The means by which control passes from a predecessor execution control state to a successor execution control state.

execution mode

The mode in which a project is executed: real-time, cycle-to-cycle, and step-by-step.

expression

A set of operators and identifiers grouped together to represent a numeric value, true or false value, or text string.

external binding list

The list of consumer groups, holding external producer variables having bindings with consumer variables defined in the project, and producer groups, holding outgoing producer variables for consumption in external bindings defined in another project.

fail operational state

A condition where a fault has been masked.

fail-safe

The ability to go to into a predetermined state when a specified malfunction occurs.

falling edge

A falling edge of a Boolean variable corresponds to a change from TRUE (1) to FALSE (0).

fault tolerance

Built-in capability of a system to provide continued correct execution of assigned functions in the presence of a limited number of hardware and software faults.

fault tolerant

The ability of a system to accept the presence of one arbitrary fault while continuing to operate correctly.

field device

Equipment, such as field wiring, sensors, final control elements, and operator interface devices, hard-wired to the field side of I/O terminals.

field power status

A DINT variable giving status data about the field power supplies for the Digital Output Module.

file mode

The mode where you save version control information to a repository located on a local or remote computer.

function

A program organizational unit which has input parameters and one output parameter. A function can be called by a program, a function or a function block. A function has no instance. It means that local data are not stored, and are generally lost from one call to the other. A function can be written using either structured text, instruction language, ladder diagram, function block diagrams, or "C" programming language.

function block

A program organizational unit which has input and output parameters and works on internal data (parameters). A program can call an instance of a function block. A function block instance cannot be called by a function (no internal data for a function). A function block can call another function block (instantiation mechanism is extended to the function blocks called). A function block can be written using either structured text, instruction language, ladder diagram, function block diagrams, or "C" programming language.

functional safety

The ability of a system to perform the actions required to maintain a safe state for procedures and the related equipment.

global scope

Scope of a declaration applying to all program organizational units of one controller.

hardware architecture

The view graphically displaying the controllers of a project and the network links between them.

Highway Addressable Remote Transducer (

HART®

)

An open protocol for process control instrumentation combining digital signals with analog signals and giving control and status data for field controllers.

healthy

A module status indicating the health of the module. The indicator is GREEN when the module is healthy and RED when there is an error.

hidden parameter

Input parameters of a function block that are not displayed in programs.

hierarchy

Architecture of a project, divided into several program organizational units. The hierarchy tree represents the links between parent programs and children programs.