I
I/O (input/output)
Devices that provide and/or receive data from the controller.
I/O block
An assembly containing a chassis, a power supply, an adapter, and I/O circuits in a single integrated package.
I/O chassis
A chassis for I/O modules and either a processor to control the I/O modules, or an adapter to interface a scanner to the I/O modules.
I/O group
A group of input and/or output circuits corresponding to a word in the input and output image tables.
I/O module
A module that interfaces directly through I/O circuits to the sensors and actuators of the machine/process in a programmable controller system.
I/O rack
An I/O addressing unit corresponding to 8 input image table words and 8 output image table words. A rack can contain a maximum of 8 I/O groups for a maximum of 128 I/O with unique addressing of I/O modules or 256 I/O with duplicate addressing.
IEC
International Electrotechnical Commission
IEC-61131 Name Standard
(The names are composed per IEC-61131, section 2.1.2.)
An identifier is a string of letters, digits, and underline characters that begin with a letter or underline character. Underlines are significant in identifiers (for example, A_BCD is interpreted differently than AB_CD). Multiple leading or multiple (consecutive) embedded underlines are not allowed, trailing underlines are not allowed, and letter case is not considered significant.
TIP:
In Logix Designer, most component names are limited in length to 40 characters or less.
import
To bring information from one system or project into another. This typically involves conversion from ASCII format. In
Logix Designer
software, specifically, this means to read in a text file representation of a control project and produce a standard Logix Designer
software project file.When you are importing project documentation into a project, the following applies:
- If the project you import the product documentation into is language neutral, then the current or default language is imported into the project.
- If language switching is enabled in the project you are importing project documentation into, then all project documentation retains the language to which it belongs. The result could be that the project you are importing project documentation into gains content for a language that, previous to the import, had no content.
- If language neutral project documentation is imported into a project that has a current language, the neutral project documentation is added to the current language (and therefore is no longer neutral project documentation).
inactive sequence
An inactive sequence is downloaded into the controller but has not received a START command to make it execute.
incremental move
A move to a specified incremental position.
incremental position
A position expressed relative to the current position. It is usually expressed in relation to a move that is an increment from the current position.
index
A reference used to select a position (an element) within an array.
inhibited connection
A connection that is configured to not communicate with its corresponding module.
InOut Parameter
For an Add-On Instruction, an InOut Parameter 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 delay time
An interval in time for detecting changes in the state of a digital input. A new state must persist for the specified delay time, or it is ignored as a glitch or noise spike in noisy environments. Values are in milliseconds, by which to delay the transition from On to Off or from Off to On, and are module-dependent.
input device
A device, such as a pushbutton or a switch, that supplies signals through input circuits to the controller.
input parameter
For an Add-On Instruction, an input parameter 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.
insert zone (I rung)
An edit zone that signifies a rung that has been inserted into a routine while in Run mode. The rung is only executed when in Test Edits mode. If you change an existing rung while in Run mode, an insert rung is also created and the original rung becomes a replace zone.
instruction
A mnemonic and data address defining an operation to be performed by the controller. A rung in a program consists of a set of input and output instructions. The input instructions are evaluated by the controller as being True or False. In turn, the controller sets the output instructions to True or False.
instruction first run
Refers to the first time an instruction is executed after prescan. The controller uses instruction first scan to read current inputs and determine the appropriate state to be in.
instruction first scan
Refers to the first time the instruction executes with a new instance of a data structure. The controller uses instruction first run to generate coefficients and other data stores that do not change for a function block after initial download.
instruction set
The set of general-purpose instructions available with a given controller.
instruction signature
The signature is an attribute that is applied by the software to indicate the contents of an Add-On Instruction at a given point in time. It is a combination of a 32-bit CRC value (Signature ID) and the date/time stamp of the Last Edit Date (Signature Timestamp), and is used to detect changes in the Add-On Instruction. It is used the same in both standard and safety Add-On Instructions.
integer (INT)
An atomic data type consisting of a word used to store a 16-bit signed integer value (-32,768 to +32,767).
integer
Any positive or negative whole number or zero.
integral control
A type of control that causes an output signal to change as a function of the rate of change in the error signal.
internal state
Displays the module’s current operational state. If the physical module does not match the module configured in the software, this field displays a hexadecimal value and this field displays "(16#xxxx) unknown." Internal states include:
- Self-test
- Flash update
- Communication fault
- Unconnected
- Flash configuration bad
- Major fault
- Run mode
- Program mode
interval
The length of time between events or states (for example, the length of time that a signal is high may be described as the interval between pulses).
inverse kinematics
The solution of target positions given source positions.
IP address
- The Internet Protocol (IP) address identifies each node on the IP network (or system of connected networks). Each TCP/IP node on a network (including the Ethernet module) must have a unique IP address.
- The IP address is 32 bits long and consists of a net ID part and a host ID part. Each network is a Class A, Class B, or Class C network. The class of a network determines how an IP address is formatted.
- Each node on the same physical network must have an IP address of the same class and must have the same net ID. Each node on the same network must have a different host ID, thereby giving it a unique IP address.
- IP addresses are written as four decimal integers separated by periods (i.e., xxx.xxx.xxx.xxx), where each integer (or xxx) is a number between 0 and 255 which gives the value of one byte of the IP address.
- The first octet of the IP Address may not be 127, or a number greater than 223.
For example, the 32-bit IP address:
00000011 00000000 00000000 00000001 is written as 3.0.0.1.
Distinguish the class of an IP address from the first integer in its dotted-decimal IP address as follows:
Range of first integer | Class of network |
0 - 127 | A |
128 - 191 | B |
192 - 223 | C |
224 - 255 | other |
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