According to the IEC standard, %I indicates a discrete input-type language object.

According to the IEC standard, %M indicates a memory bit-type language object.

According to the IEC standard, %MW indicates a memory word-type language object.

According to the IEC standard, %Q indicates a discrete output-type language object.

This is a binary unit for a quantity of information which can represent two distinct values (or statuses): 0 or 1.

BOOL is the abbreviation of Boolean type. This is the elementary data item in computing. A BOOL type variable has a value of either: 0 (FALSE) or 1 (TRUE).

A BOOL type word extract bit, for example: %MW10.4.

When 8 bits are put together, this is called a BYTE. A BYTE is either entered in binary, or in base 8.

The BYTE type is coded in an 8 bit format, which, in hexadecimal, ranges from 16#00 to 16#FF

DFB is the abbreviation of Derived Function Block.

DFB types are function blocks that can be programmed by the user ST, IL, LD or FBD.

By using DFB types in an application, it is possible to:

A DFB type instance occurs when an instance is called from a language editor.

The instance possesses a name, input/output interfaces, the public and private variables are duplicated (one duplication per instance, the code is not duplicated).

A DFB type can have several instances.

EBOOL is the abbreviation of Extended Boolean type. It can be used to manage rising or falling edges, as well as forcing.

An EBOOL type variable takes up one byte of memory.

Is the abbreviation for Elementary Function Block.

This is a block which is used in a program, and which performs a predefined software function.

EFBs have internal statuses and parameters. Even where the inputs are identical, the output values may be different. For example, a counter has an output which indicates that the preselection value has been reached. This output is set to 1 when the current value is equal to the preselection value.

FBD is the abbreviation of Function Block Diagram.

FBD is a graphic programming language that operates as a logic diagram. In addition to the simple logic blocks (AND, OR, etc.), each function or function block of the program is represented using this graphic form. For each block, the inputs are located to the left and the outputs to the right. The outputs of the blocks can be linked to the inputs of other blocks to form complex expressions.

View making it possible to see the program part of the application through the functional modules created by the user (see Functional module definition).

International standard: Programmable Logic Controls

Part 3: Programming languages.

IL is the abbreviation of Instruction List.

This language is a series of basic instructions.

This language is very close to the assembly language used to program processors.

Each instruction is composed of an instruction code and an operand.

To instantiate an object is to allocate a memory space whose size depends on the type of object to be instantiated. When an object is instantiated, it exists and can be manipulated by the program.

INT is the abbreviation of single integer format (coded on 16 bits).

The lower and upper limits are as follows: -(2 to the power of 31) to (2 to the power of 31) - 1.

Example:

-32768, 32767, 2#1111110001001001, 16#9FA4.

LD is the abbreviation of Ladder Diagram.

LD is a programming language, representing the instructions to be carried out in the form of graphic diagrams very close to a schematic electrical diagram (contacts, coils, etc.).

A located variable is a variable for which it is possible to know its position in the PLC memory. For example, the variable Water_pressure, is associated with %MW102. Water_pressure is said to be located.

Main program task.

It is obligatory and is used to carry out sequential processing of the PLC.

This is an editor that is integrated into Control Expert, which is used to facilitate the operation of an automated process. The user regulates and monitors the operation of the installation, and, in the case of any unexpected event, can act quickly and simply.

Real type is a coded type in 32 bits.

When a calculation result is:

Program module belonging to a task which can be written in the language chosen by the programmer (FBD, LD, ST, IL, or SFC).

A task can be composed of several sections, the order of execution of the sections corresponding to the order in which they are created. This order is modifiable.

SFC is the abbreviation of Sequential Function Chart.

SFC enables the operation of a sequential automation device to be represented graphically and in a structured manner. This graphic description of the sequential behavior of an automation device, and the various situations which result from it, is provided using simple graphic symbols.

An SFC object is a data structure representing the status properties of an action or transition of a sequential chart.

ST is the abbreviation of Structured Text language.

Structured Text language is an elaborated language close to computer programming languages. It enables you to structure series of instructions.

View in the project navigator with represents the project structure.

Program module belonging to a task (MAST, FAST) which can be written in the language chosen by the programmer (FBD, LD, ST, or IL).

A subroutine may only be called by a section or by another subroutine belonging to the task in which it is declared.

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 PLC. These I/O are refreshed in consequence.

The type TIME expresses a duration in milliseconds. Coded in 32 bits, this type makes it possible to obtain periods from 0 to (2 to the power of 32)-1 milliseconds.

An unlocated variable is a variable for which it is impossible to know its position in the PLC memory. A variable which have no address assigned is said to be unlocated.

Memory entity of the type BOOL, WORD, DWORD, etc., whose contents can be modified by the program during execution.

The WORD type is coded in 16 bit format and is used to carry out processing on bit strings.

This table shows the lower/upper limits of the bases which can be used:

Representation examples