E

edit

To create or modify a ladder program.

edit zone

In the function block diagram editor, the entire routine is the edit zone.

In the ladder editor, an edit zone refers to a logic change to a rung that was transferred to the controller but not yet assembled. Edit zones are shown with an upper-case letter (I, R, or D) to the left of the rung. In Run mode, a rung with an edit zone may or may not be executing based on whether the program is in Test Edits mode or Untest Edits mode.

elapsed time

The total time required for the execution of all operations configured within a single task. If the controller is configured to run multiple tasks at one time, elapsed time includes any time used/shared by other tasks performing other operations.

EnableInFalse

When defined and enabled for an Add-On Instruction, the EnableInFalse routine executes when the rung condition is false or the EnableIn parameter of the Add-On Instruction is false (0). This is useful primarily for scan false logic when used as an output instruction in a Ladder routine.

encoder

A feedback element that converts linear or rotary position (absolute or incremental) into a digital signal. The types are:

encoder bandwidth

An expression for maximum encoder speed in Hz. This may also refer to the maximum rate at which the control loop can accept encoder signals. The actual bandwidth of the encoder and the capability of the controller to process encoder signals may not be the same.

encoder line count

The number of cycles (lines) per revolution on an encoder channel.

encoder marker

A once-per-revolution signal provided by some incremental encoders to specify a reference point within that revolution. This is also known as the zero reference signal.

encoder multiplication

A technique by which encoder resolution can be raised above the encoder line count (normally from 2 to 4 times the line count).

encoder resolution

A measure of the smallest positional change that can be detected by the encoder. For a rotary encoder, this is the number of lines per revolution times the encoder multiplier.

endpoint

Both ends of a connection.

An endpoint provides the connection details of the tag, member, or bit as input (connection to the endpoint) and output (connection from the endpoint).

energize

To enable or turn On a value.

engineering units

The units of measure (for example, pounds, pounds per square inch, degrees Celsius) relative to the process. An input signal is often a percentage of the full-scale range (such as ± 5 Volts, or 4-20mA) of direct measurement that must then be converted, through scaling, into engineering units.

ENQ transmit limit

The number of inquiries (ENQs) to send after an ACK timeout.

equipment phase instructions

The set of

Logix Designer

instructions that can be used in ladder and structured text programs to interact with

Equipment Phase

s.

equipment sequence

An Equipment Sequence is a series of Equipment Phases. The phases automatically run when the sequence is started, based on an order defined by the sequence.

Equipment Sequence Editor

The

Equipment Sequence

Editor is used to create

Equipment Sequence

programs and configure sequencing parameters and step tags. The sequence program has one routine, sequencing parameters, and step tags.

Equipment Sequence Properties

The

Equipment Sequence

Properties

dialog box has four tabs to set the properties of an

Equipment Sequence

. The

General

tab modifies the

Equipment Sequence

information, including the name, description, parent, task scheduled in, revision, and revision note. The

Configuration

tab is used to inhibit an

Equipment Sequence

, retain the Sequence ID, generate sequence events, set the Unit ID, and select which value is used when starting and resetting

Equipment Sequence

s. The

Parameters

tab is used to edit and create the sequencing parameters for the

Equipment Sequence

. Use the

Monitor

tab to view maximum and last scan times, current sequence state and substate, current owners of the

Equipment Sequence

, the Unit ID of the

Equipment Sequence

, and the Sequence ID of the

Equipment Sequence

.

equipment sequence topology

An equipment sequence topology is a specific combination of sequence elements (steps, links, and transitions). Sequence topologies include steps, transitions, and branches arranged as simple, simultaneous, selective, and loop series.

error (deviation)

The difference between the setpoint signal and the feedback signal in any control loop. (An error is necessary before a correction can be made in the controlled system.)

OR

The difference between the instantaneous position command signal generated by the summation of the feedrate, and the actual position signal generated by the summation of the feedback in a positioning loop.

error signal

The difference between a feedback signal and its corresponding command signal.

Ethernet network

A local area network with a baseband communication rate of 10M bit/s.

event task

A task that performs a specific function when triggered by a specified event. When the event task is triggered, it interrupts any lower priority tasks, executes one time, and returns control to the task that was interrupted, at the point at which it was interrupted.

The trigger for the event task can be:

execution

The performance of an operation accomplished through processing an instruction, a series of instructions, or a complete program.

execution model

A hierarchy (graphical tree) of programs, files, and links in the Controller Organizer that contains all the information about the current project; compare to the logical model displayed in the Logical Organizer.

execution number

The number indicating a function block’s position in the order of execution.

execution time

The total time required for execution of a single program. If the controller is configured to run multiple tasks at one time, execution time includes only the time used by that single program. It excludes any time used/shared by programs in other tasks performing other operations.

exponential

The real values displayed and entered in scientific or exponential format notation. The number is always displayed with one digit to the left of the decimal point, followed by the other digits, and then an exponent. For example, 123.45678 would be displayed as 1.2345678e+002.

export

To transfer information from one system or program to another. This typically involves conversion to ASCII format. For

Logix Designer

, specifically, this means to produce an ASCII, CSV, or XML representation of a project or a project component.

Extended Data Table (EDT)

A mechanism that increases the amount of configuration data that a module-type can support. It also provides mechanisms to allow large amounts of data to be paged to and from a module.

External Access

A property that allows you to specify the level of access (Read-Only, Read/Write, or None) external applications and devices have to tags.