Glossary

access

The granting of permissions to user accounts or resources that give them rights to act within the organization.

ACD

Automation Controller Database. Used to store Logix Designer projects.

administrator

A predefined set of permissions that provides a designated user account the ability to control access to services and devices and to specify the operational configuration for the organization.

alarms

Notification that alert you to conditions that meet a set of defined state criteria. The Logix-based alarm instructions are available in ladder diagram, structured text, and function block diagram.

alias tag

A tag that references memory defined by another tag. An alias tag may refer to another alias tag or a base tag. An alias tag may also refer to memory within another tag by referencing a member of a structure tag, or a bit within an integer tag or member.

ALMA

Alarm instruction that provides alarms based on level and rate-of-change of analog signals. Evaluates a single analog tag against up to four limit values (high-high, hi, low, and low-low) and up to two rate of change limits (positive and negative)

ALMD

Alarm instruction that provides alarms based on a discrete Boolean value from the controller obtained by scanning the controller for a defined alarm state. A digital alarm monitors a tag for alarm conditions based on whether the tag is equal or not equal to zero. Each value represent a specific alarm condition.

array

A numerically indexed sequence of elements of the same data type.

asset

Physical or logical object under the custodial duties of an organization having either perceived or actual value to the organization. Examples: controllers, HMIs, drives, networking equipment, PCs, software, machines, and so on.

atomic tag

Tags whose value is defined by an atomic data type. This includes BOOL, SINT, INT, DINT, and REAL data types.

authority

A central location for the granting of policy and providing / validating device and user identity. There are three types of authorities, identity authority, certificate authority and policy authority.

automatic output processing

At the end of a task the outputs of the task are automatically sent to the I/O module.

axis

A straight line around which an object rotates. Motion control systems use instructions to control movement from the axes home position or offset position

class

The class of the program, either Standard or Safety.

consumed tags

Tags that get data from a producing tag in another controller.

contributor

A predefined set of permissions that give the designated user account access to resources and the ability to create, read, update, and delete subordinate objects of those resources, but do not allow change of organizational settings.

control module

In ISA-88, a term for a module that performs equipment control to directly manipulate devices, actuators and other control modules (e.g. Valve, Motor, Clamp, Photo Eye, etc.). Control modules contain basic control which is normally either regulatory or state oriented (or both). Regulatory control is dedicated to maintaining a process variable or variables at or near some desired value. State-oriented control refers to setting the state of a piece of equipment as opposed to the state of a process variable or variables.

controller

A device that controls machines or processes elements (for example, a programmable controller or relay panel).

controller fault

A trapped condition where normal or correct operation of the controller may be interrupted. The condition may be a program fault or another condition. Faults are categorized by severity into major faults and minor faults. Faults can be trapped by a fault routine or a controller fault handler program to take corrective action.

controller fault handler

A program that can be configured to handle major faults. All program faults that are not handled by a fault routine execute this program (as well as any other kind of major fault).

controller tags

A tag at controller scope. The tag data is accessible from anywhere in the controller. The controller contains a collection of tags that can be referenced by the routines and aliases in any program, as well as other aliases in the controller scope.

CST master

The coordinated system time (CST) clock that other modules use for time synchronization.

entitlement

Making an application usable by an organization.

equipment phase

An equipment phase is a special kind of program. A state machine built into the program manages the state of the equipment phase. The state specifies which routine the phase executes. The phase can be commanded to change states, and change the routine it is executing. Equipment phase programs have input and output parameters. Parameters can be configured as Sequencing parameters, marking these tags as requiring data to be supplied from an internal sequencer (such as Sequence Manager) or external sequencer (such as FactoryTalk Batch).

fault

A problem or error detected by the control system hardware or software. A fault is identified by an error code or an error bit.

fault routine

A routine that is configured to execute when a program fault occurs.

function block diagram (FBD)

A graphical programming language for the controller that describes the function between input variables and output variables. Each function is described as a set of blocks. Input and output variables are connected to blocks by connection lines.

inhibited connection

A connection that is configured to not communicate with its corresponding module.

InOut parameters

Defines data that is used as both input and output during the execution of the instruction. An InOut Parameter is passed by reference, meaning the logic deals directly with the tag passed to the instruction. InOut parameters can be any valid data type because they are passed by reference. This includes message, motion group, all axis, and module data types. Any data structures or arrays that need to be passed to an Add-On Instruction must be done using InOut parameters

input parameters

Defines data that is passed into the instruction. The value is passed to the instruction before execution. The parameter’s value is also accessible through a member of a tag, which is of the Add-On Instruction’s data type. An input parameter also holds a value designed to specify how a sequence or procedure is to execute. Input Parameters can accept a literal value or a tag as an argument. The data type of an input parameter can be any valid atomic data type.

instruction-based alarms

Alarms that are evaluated as part of an instruction. There are two types, ALMA and ALMD.

inter-processor communication

The configuration of produced and consumed tags that enables data to be passed between controllers.

JSR parameters

The configuration of the input parameter and return parameter for the Jump to Subroutine (JSR) instruction.

ladder diagram (LD)

A ladder-like diagram that represents a program written in ladder logic. Main LD elements are:

• Rungs

• Instructions

• Branches

• Branch wires

local tags

Data that is used only within an instruction and not passed to another part of the program.

main routine

The routine in the program configured to execute first when the program runs.

notification

A message from the system about an operation that occurred.

organization

A set of associated user accounts, applications, and resources that are managed together.

output parameters

Data that is produced as a direct result of executing the instruction. The data type for output parameters can be any valid atomic data type.

periodic rate

The length of time for a cyclical operation to complete one full cycle.

personal tenant

A set of applications and resources that are scoped to an individual user account.

power up handler

A program configured to handle startup execution after an abnormal loss of power in Run mode.

priority

The order of task execution. If two tasks are triggered at the same time, the task with the higher priority will execute first. Priorities range from 1 to 15 with 1 being the highest priority. If two tasks with the same priority are triggered at the same time, the controller switches between them every millisecond. A continuous task runs at a fixed priority lower than all other tasks in the controller.

produced tags

A tag that a controller makes available for use by other controllers. Produced tags are always at controller scope.

profile

A collection of information that distinguishes a unique user account.

program

A program executes a set of instructions in a project.

project components

The building blocks of a project. Includes: tasks, programs, routines, modules, data types, tags, axes, motions groups, and messages.

project file

The file that stores a controller’s programming and configuration information.

public parameters

A parameter that operates like a local program scoped tag, but other parameters and controller scope tags can communicate with it through connections and bindings. A Public parameter is meant to be an encapsulated version of a controller scope tag, and typically it is used for large data structures that need to be shared among programs.

redundancy

The use of multiple similar devices, such that if one fails, the remaining device(s) take over the assigned functions, thus improving the devices’ availability.

resources

Devices or groups that can be managed within the organization.

role

The set of responsibilities and associated permissions assigned to a user account or resource.

routine

A sequence of logic that is executed as a block.

safety-locked

A project that has been restricted to utilize only safety approved instructions and data types. Locking the Safety application protects the application from unauthorized changes, and prevents editing of safety components, such as safety task, safety programs, safety routines, safety Add-On Instructions, safety tags, safety I/O, and safety task signature. To make changes, unlock the project in Logix Designer before uploading the project to your vault.

security authority identifier

A unique ID generated for each FactoryTalk Directory scope object to differentiate one directory from another.

sequential function chart (SFC)

A graphical programming language for the controller used to program processes that can be split into steps. Main components of SFC are:

• Steps with associated actions

• Transitions with associated logic conditions

• Directed links between steps and transitions

services

Technologies available from the FactoryTalk Hub that provide support for industrial automation applications and solutions.

source protection

Program components can be source protected to prevent unauthorized editing or viewing. Components can be protected using either a license or a source key.

structured text (ST)

A text-based programming language based on structure block statements. Main components of ST are:

• Iterative loops

• Condition statements

• Functions

structures

A data type composed of a sequence of members. A structure tag occupies a contiguous block of memory in the controller with each member in sequence in memory.

switchover

For redundancy enabled systems, the process of changing from the primary system to the secondary system.

tag

A named area of the process-connected device or controller’s memory where data is stored. It is the basic mechanism for allocating memory, referencing data from logic, and monitoring data.

task

A scheduling mechanism for executing a program. A maximum of 32 programs can be scheduled to execute when a task is triggered; for ControlLogix, the maximum number of programs is 1,000. A task can be configured to run as a continuous task or a periodic task. A maximum of 32 tasks can be created to schedule programs.

tenant

A user or an organization that have specific privileges to an instance of a service. Each tenant is distinct and separate from other tenants.

vault

A cloud service for securely storing and accessing projects.

watchdog

A term used to specify how long a task can run before triggering a watchdog controller fault.