According to the IEC standard, %MW represents a memory word register (for example, a language object of type memory word).
A program including configuration data, symbols, and documentation.
The systematic arrangement of data objects of a single type in the form of a table defined in logic controller memory. The syntax is as follows: ARRAY [<dimension>] OF <Type>
Example 1: ARRAY [1..2] OF BOOL is a 1-dimensional table with 2 elements of type BOOL.
Example 2: ARRAY [1..10, 1..20] OF INT is a 2-dimensional table with 10 x 20 elements of type INT.
(boolean) A basic data type in computing. A BOOL variable can have one of these values: 0 (FALSE), 1 (TRUE). A bit that is extracted from a word is of type BOOL; for example, %MW10.4 is a fifth bit of memory word number 10.
(boot application) The binary file that contains the application. Usually, it is stored in the controller and allows the controller to boot on the application that the user has generated.
(bootstrap protocol) A UDP network protocol that can be used by a network client to automatically obtain an IP address (and possibly other data) from a server. The client identifies itself to the server using the client MAC address. The server, which maintains a pre-configured table of client device MAC addresses and associated IP addresses, sends the client its pre-configured IP address. BOOTP was originally used as a method that enabled diskless hosts to be remotely booted over a network. The BOOTP process assigns an infinite lease of an IP address. The BOOTP service utilizes UDP ports 67 and 68.
A type that is encoded in an 8-bit format, ranging from 00 hex to FF hex.
(continuous function chart) A graphical programming language (an extension of the IEC 61131-3 standard) based on the function block diagram language that works like a flowchart. However, no networks are used and free positioning of graphic elements is possible, which allows feedback loops. For each block, the inputs are on the left and the outputs on the right. You can link the block outputs to the inputs of other blocks to create complex expressions.
The arrangement and interconnection of hardware components within a system and the hardware and software parameters that determine the operating characteristics of the system.
A network containing logic controllers, SCADA systems, PCs, HMI, switches, ...
Two kinds of topologies are supported:
oflat: all modules and devices in this network belong to same subnet.
o2 levels: the network is split into an operation network and an inter-controller network.
These two networks can be physically independent, but are generally linked by a routing device.
(cyclical redundancy check) A method used to determine the validity of a communication transmission. The transmission contains a bit field that constitutes a checksum. The message is used to calculate the checksum by the transmitter according to the content of the message. Receiving nodes, then recalculate the field in the same manner. Any discrepancy in the value of the 2 CRC calculations indicates that the transmitted message and the received message are different.
(dynamic host configuration protocol) An advanced extension of BOOTP. DHCP is more advanced, but both DHCP and BOOTP are common. (DHCP can handle BOOTP client requests.)
(double word) Encoded in 32-bit format.
The short name of the ARRAY element.
A physical and data link layer technology for LANs, also known as IEEE 802.3.
(Ethernet industrial protocol) An open communications protocol for manufacturing automation solutions in industrial systems. EtherNet/IP is in a family of networks that implement the common industrial protocol at its upper layers. The supporting organization (ODVA) specifies EtherNet/IP to accomplish global adaptability and media independence.
(function block) A convenient programming mechanism that consolidates a group of programming instructions to perform a specific and normalized action, such as speed control, interval control, or counting. A function block may comprise configuration data, a set of internal or external operating parameters and usually 1 or more data inputs and outputs.
Represents the BIOS, data parameters, and programming instructions that constitute the operating system on a controller. The firmware is stored in non-volatile memory within the controller.
A non-volatile memory that can be overwritten. It is stored on a special EEPROM that can be erased and reprogrammed.
A programming unit that has 1 input and returns 1 immediate result. However, unlike FBs, it is directly called with its name (as opposed to through an instance), has no persistent state from one call to the next and can be used as an operand in other programming expressions.
Examples: boolean (AND) operators, calculations, conversions (BYTE_TO_INT)
A programming unit that has 1 or more inputs and returns 1 or more outputs. FBs are called through an instance (function block copy with dedicated name and variables) and each instance has a persistent state (outputs and internal variables) from 1 call to the other.
Examples: timers, counters
One of the 5 languages for logic or control supported by the standard IEC 61131-3 for control systems. Function block diagram is a graphically oriented programming language. It works with a list of networks where each network contains a graphical structure of boxes and connection lines representing either a logical or arithmetic expression, the call of a function block, a jump, or a return instruction.
(global variable list) Manages global variables within an EcoStruxure Machine Expert project.
(hexadecimal)
(input/output)
(identifier/identification)
(international electrotechnical commission) A non-profit and non-governmental international standards organization that prepares and publishes international standards for electrical, electronic, and related technologies.
Part 3 of a 3-part IEC standard for industrial automation equipment. IEC 61131-3 is concerned with controller programming languages and defines 2 graphical and 2 textual programming language standards. The graphical programming languages are ladder diagram and function block diagram. The textual programming languages include structured text and instruction list.
A collection of IEEE standards defining the physical layer, and the media access control sublayer of the data link layer, of wired Ethernet.
(instruction list) A program written in the language that is composed of a series of text-based instructions executed sequentially by the controller. Each instruction includes a line number, an instruction code, and an operand (refer to IEC 61131-3).
(integer) A whole number encoded in 16 bits.
(Internet protocol Part of the TCP/IP protocol family that tracks the Internet addresses of devices, routes outgoing messages, and recognizes incoming messages.
(ladder diagram) A graphical representation of the instructions of a controller program with symbols for contacts, coils, and blocks in a series of rungs executed sequentially by a controller (refer to IEC 61131-3).
(long word) A data type encoded in a 64-bit format.
(media access control address) A unique 48-bit number associated with a specific piece of hardware. The MAC address is programmed into each network card or device when it is manufactured.
A processor task that is run through its programming software. The MAST task has 2 sections:
oIN: Inputs are copied to the IN section before execution of the MAST task.
oOUT: Outputs are copied to the OUT section after execution of the MAST task.
A system of interconnected devices that share a common data path and protocol for communications.
(programmable logic controller) An industrial computer used to automate manufacturing, industrial, and other electromechanical processes. PLCs are different from common computers in that they are designed to have multiple input and output arrays and adhere to more robust specifications for shock, vibration, temperature, and electrical interference among other things.
(program organization unit) A variable declaration in source code and a corresponding instruction set. POUs facilitate the modular re-use of software programs, functions, and function blocks. Once declared, POUs are available to one another.
The component of an application that consists of compiled source code capable of being installed in the memory of a logic controller.
A convention or standard definition that controls or enables the connection, communication, and data transfer between 2 computing system and devices.
A command that causes the controller to scan the application program, read the physical inputs, and write to the physical outputs according to solution of the logic of the program.
(structured text) A language that includes complex statements and nested instructions (such as iteration loops, conditional executions, or functions). ST is compliant with IEC 61131-3.
A command that causes the controller to stop running an application program.
A variable that is a series of ASCII characters.
A variable that provides controller data and diagnostic information and allows sending commands to the controller.
A group of sections and subroutines, executed cyclically or periodically for the MAST task or periodically for the FAST task.
A task possesses a level of priority and is linked to inputs and outputs of the controller. These I/O are refreshed in relation to the task.
A controller can have several tasks.
(transmission control protocol) A connection-based transport layer protocol that provides a simultaneous bi-directional transmission of data. TCP is part of the TCP/IP protocol suite.
(unsigned double integer) Encoded in 32 bits.
(unsigned integer) Encoded in 16 bits.
A variable that does not have an address (refer to located variable).
A memory unit that is addressed and modified by a program.
A watchdog is a special timer used to ensure that programs do not overrun their allocated scan time. The watchdog timer is usually set to a higher value than the scan time and reset to 0 at the end of each scan cycle. If the watchdog timer reaches the preset value, for example, because the program is caught in an endless loop, an error is declared and the program stopped.
A type encoded in a 16-bit format.
