Complex Data Types in TIA Portal

 In TIA Portal, complex data types refer to data structures that are not simple (like BOOL, INT, REAL, etc.), but instead combine multiple different data types into a single, more organized unit. These complex types are typically used when you need to handle grouped data efficiently, such as sensor readings, equipment status, or any scenario where multiple pieces of information need to be bundled together.

Here are the primary complex data types in TIA Portal:

1. Structures (Struct)

• Description: A Structure (often referred to as STRUCT) is a custom data type that combines multiple variables of different types into a single unit. Each element within the structure can be a different data type, and the structure itself can be treated as a single variable.
• Use Case: Structures are useful for organizing complex data that logically belong together, like representing a machine’s state with its various attributes (speed, temperature, status, etc.).
• How to Define a Structure:
  • You can define a structure in the Data Block or as a Type under the "Types" section.

Example of a Structure:

TYPE MotorStatus :
    STRUCT
        Running     : BOOL;   // Motor is running (TRUE/FALSE)
        Speed       : REAL;   // Motor speed in RPM
        Temperature : REAL;   // Motor temperature in Celsius
        Voltage     : REAL;   // Motor voltage
    END_STRUCT;
END_TYPE

In this example, MotorStatus is a structure that combines the motor's Running status (a boolean), Speed (a real number), Temperature (a real number), and Voltage (a real number).

Usage Example:

VAR
    Motor1Status : MotorStatus;  // Variable of type MotorStatus
END_VAR

You can access individual fields of the structure as follows:

Motor1Status.Speed := 1500.0;      // Set speed
Motor1Status.Running := TRUE;      // Set motor running status

2. Arrays

• Description: An Array is a collection of elements of the same data type that are indexed by an integer. Arrays are used when you need to store and process a list of values (e.g., a set of sensor readings or control outputs).
• Use Case: Arrays are commonly used when you need to handle a series of similar items (e.g., multiple sensor values, conveyor belt speeds, etc.).
• How to Define an Array:
  • Arrays can be defined with a specified number of elements. The array index is typically zero-based (first element = 0).

Example of an Array:

VAR
    SensorData : ARRAY[0..9] OF REAL;   // Array of 10 real numbers (sensor values)
END_VAR

• Access elements in the array:

SensorData[0] := 23.5;   // Set the value of the first element (sensor 1)
SensorData[1] := 26.8;   // Set the value of the second element (sensor 2)

Array of Structures Example:

If you need to combine both concepts (arrays of structures):

VAR
    MotorStatusArray : ARRAY[0..4] OF MotorStatus;   // Array of MotorStatus structures
END_VAR

You can access the fields of a structure inside an array like this:

MotorStatusArray[0].Speed := 1200.0;   // Set speed for the first motor
MotorStatusArray[1].Running := TRUE;   // Set running status for the second motor

3. Union

• Description: A Union is a special data type that allows multiple different data types to share the same memory space. Only one of the union members can hold a value at any time, but the memory allocation is shared. Unions are often used when you want to represent different types of data that do not need to coexist at the same time.
• Use Case: Unions are used in cases where the memory space is limited, and you need to store different types of data, but only one at a time.
• How to Define a Union:
  • You can define a union similarly to how you define a structure but with the understanding that only one member will hold a value at a time.

Example of a Union:

TYPE SensorDataUnion :
    UNION
        Temperature : REAL;   // Temperature data
        Pressure     : REAL;   // Pressure data
        Flow         : REAL;   // Flow rate data
    END_UNION;
END_TYPE

• You can assign values to different fields, but only one will be valid at any given time:

VAR
    SensorData : SensorDataUnion;
END_VAR

SensorData.Temperature := 35.0;  // Store temperature data
SensorData.Pressure := 101.3;    // Store pressure data (this overwrites temperature)

4. Pointer

• Description: A Pointer is a variable that stores the address of another variable (or memory location) rather than a value itself. This allows for indirect addressing and is used in more advanced applications like dynamic memory management or data manipulation.
• Use Case: Pointers are generally used for advanced programming techniques and are more common in complex automation systems, such as dynamically allocated memory for large datasets or interfacing with external devices.
• How to Define a Pointer:
  • Pointers are typically defined by the type they will point to. For example, a pointer to a REAL type would be defined as REAL_POINTER.

5. Data Block (DB)

• Description: A Data Block is a block of memory in the PLC where variables are stored. It can contain any type of data, including complex data types like arrays and structures. DBs are used to store data persistently across multiple program cycles and are often used for storing machine states, configurations, or parameters.
• Use Case: Data blocks are ideal for holding structured or grouped data and for managing information that should be accessible across different parts of the program.
• How to Define a Data Block:
  • A Data Block is created under the "Program Blocks" section in TIA Portal and can contain any type of variable (including complex types).

Example:

A Data Block might contain a MotorStatus structure for different motors in a machine:

DATA_BLOCK MotorDB
    Motor1Status : MotorStatus;
    Motor2Status : MotorStatus;
END_DATA_BLOCK

In the program, you can access each motor's status as:

MotorDB.Motor1Status.Speed := 1500.0;   // Set the speed of Motor 1
MotorDB.Motor2Status.Running := TRUE;   // Set the running status of Motor 2

6. Tags (Alias)

• Description: Tags in TIA Portal are user-defined names that refer to variables or data structures, making it easier to interact with complex data types (like structures or arrays) in a more intuitive way. Tags are often used to interface with HMI, SCADA, or external systems.
• Use Case: Tags are particularly useful when integrating PLC systems with HMI or SCADA systems, where human-readable names make programming easier.
• How to Define Tags:
  • Tags are defined under Global Data Blocks or within Instance DBs for function blocks.

Summary of Complex Data Types in TIA Portal:

• Structures (STRUCT): Grouping of multiple variables with different data types.
• Arrays: Collection of elements of the same data type, indexed by an integer.
• Unions: A data type that allows multiple members to share the same memory space.
• Pointers: A variable that stores the memory address of another variable.
• Data Blocks (DB): A container that stores a collection of variables, including complex data types.
• Tags: User-defined names for variables, often used in HMI/SCADA systems.

Using these complex data types, you can organize your PLC program more efficiently and tailor the data structure to meet the needs of your specific application, especially in large or more complex systems.