Ladder Logic is a programming language used to program PLCs (Programmable Logic Controllers), which are commonly used in industrial control systems and automation. Ladder Logic is graphical in nature and is based on the idea of relay ladder diagrams. Some commonly used terms in Ladder Logic include:
- Addressing: Addressing is the process of assigning a unique address or identifier to each input and output in a PLC program.
- Advanced Control: Advanced control uses advanced algorithms and techniques, such as neural networks or fuzzy logic, to control industrial processes.
- Alarm Management: Alarm management is the process of configuring and managing alarms that are triggered by certain conditions within a system.
- AND gate: An AND gate is a logic gate that outputs a high signal (1) only if all of its input signals are high. In Ladder Logic, an AND gate is represented by a normally open contact in series with one or more other contacts.
- Array: An array is a collection of variables of the same type that are referred to by a single name and can be accessed by an index number.
- Bit Logic: Bit logic instructions are used to perform logical operations on individual bits within a word or integer.
- Bit Mask: Bitmask instructions are used to mask or clear specific bits in a word or integer.
- Bit Shift: Bit shift instructions are used to shift the bits of a word or integer to the left or right.
- Call instruction: Call instruction is used to call a subroutine and transfer control of the program to that subroutine.
- Call target: Call target is the label or instruction of the subroutine that a call instruction transfers control to.
- Cloud-Based: Cloud-based refers to systems or services that are hosted on remote servers and accessed over the internet.
- Coil: A coil is a graphical representation of an output in a ladder logic diagram. It can be used to turn on or off a device, such as a motor or a valve.
- Compare value: Compare value is the value that a compare instruction compares its input to.
- Compare: Instructions that are used to compare two values and take action based on the result.
- Contact: A contact is a graphical representation of a switch in a ladder logic diagram. It can be either normally open (NO) or normally closed (NC).
- Count Up/Count Down: Count up and count down refer to the direction of counting for a counter instruction.
- Counter: Counter instructions are used to count the number of times a contact is opened or closed.
- Cybersecurity: Cybersecurity protects industrial control systems from unauthorized access, attacks, or breaches.
- Data Block: A data block is a collection of data elements that are grouped together for easy manipulation.
- Data Conversion: Data conversion instructions are used to convert data from one format or data type to another.
- Data File: Data file is a memory area in a PLC that is used to store data that is used by the program, but that does not need to be retained when the power is turned off.
- Data Logging: Data logging is the process of recording data over time for later analysis.
- Data Manipulation: Data manipulation instructions are used to perform various operations on data stored in memory.
- Data Move: Data move instructions are used to move data between memory locations.
- Data Rounding: Data rounding instructions are used to round data to a specified number of decimal places.
- Data Scaling: Data scaling instructions are used to scale data to a different range or units.
- Data Table: A data table is a memory area in a PLC that stores data such as input, output, and internal variables.
- Data Types: Data types are used to define the type of data stored in a memory location. Common data types include integers, floating-point numbers, and strings.
- Debugging: Debugging is the process of identifying and correcting errors in a program.
- Edge Computing: Edge computing refers to the use of computing resources located at or near the edge of a network, rather than in a central location.
- Error flag: Error flag is a special type of flag that is set when an error or fault condition is detected.
- Event-driven Programming: Event-driven programming is a method of programming PLCs that uses events, such as sensor inputs or timer expirations, to trigger actions in the program.
- File Comparison: File comparison instructions are used to compare the contents of two memory locations.
- File Handling: File handling instructions are used to read and write data to and from file registers.
- File Pointer: A file pointer is a special type of register that is used to store the current position when reading or writing to a file register.
- File Register: A file register is a special type of register that is used to store data that needs to be retained when the PLC power is turned off.
- File Register: File register is a memory area in a PLC that is used to store data that needs to be retained when the PLC power is turned off.
- Function Block Diagram (FBD): Function Block Diagram is a graphical programming language that is used to program PLCs. It is similar to ladder logic, but it allows for more advanced control and data manipulation.
- Global variable: Global variable is a variable that can be accessed from any part of the program, as opposed to a local variable which can only be accessed within a specific subroutine.
- Historian: Historian is a software or hardware system that is used to collect and store historical data from a PLC or other industrial control system.
- HMI (Human-Machine Interface): HMI is a user interface that allows operators to interact with and control industrial processes.
- Index register: An index register is a special type of register that is used to store the index value when accessing an array or a lookup table.
- Industrial Internet of Things (IIoT): IIoT refers to the application of IoT technologies to industrial systems and processes.
- Input: Inputs are the signals that are received by the PLC from devices such as sensors or push buttons.
- Interrupt instruction: Interrupt instruction is used to interrupt the normal flow of the program to perform a specific task or routine.
- Interrupt: An interrupt is a signal that temporarily halts the normal execution of a program and transfers control to a special routine known as an interrupt service routine (ISR) or interrupt handler.
- IoT (Internet of Things): IoT refers to the interconnectedness of physical devices, such as sensors and industrial control systems, with the internet.
- Jump instruction: Jump instruction is used to transfer the control of the program to a specific location or label.
- Jump target: Jump target is the label or instruction to which a jump instruction transfers control.
- Ladder Logic Editor: Ladder Logic Editor is a software tool used to create, edit, and debug ladder logic programs.
- Ladder Logic Programmer: Ladder Logic Programmer is a software tool used to create, edit, and debug ladder logic programs.
- Lookup Table: A lookup table is a collection of data that is stored in a memory location and can be accessed using an index number.
- Machine Learning: Machine learning is a type of artificial intelligence that allows systems to learn and improve from data without being explicitly programmed.
- Master Control Relay (MCR): Master Control Relay is a special type of coil that is used to control the overall operation of a PLC program.
- Math instruction: Math instruction is used to perform mathematical operations such as addition, subtraction, multiplication, and division on data stored in memory.
- Move instruction: Move instruction is used to move data from one memory location to another.
- NOT gate: A NOT gate is a logic gate that inverts the input signal. In Ladder Logic, a NOT gate is represented by a normally closed contact.
- OPC (OLE for Process Control): OPC is a standard for communication between industrial control systems and software applications. It allows for the exchange of data between different systems, such as PLCs, SCADA systems, and Historians.
- OR gate: An OR gate is a logic gate that outputs a high signal (1) if any of its input signals are high. In Ladder Logic, an OR gate is represented by a normally open contact in parallel with one or more other contacts.
- Output: Outputs are the signals that are sent by the PLC to control devices such as motors or valves.
- PLC Hardware: PLC hardware refers to the physical components that make up a PLC, including the CPU, memory, input/output modules, and communication interfaces.
- Predictive Maintenance: Predictive maintenance is the use of machine learning and other techniques to predict when maintenance or repairs will be needed, based on data from sensors and other sources.
- Preset: Preset refers to the initial value of a counter instruction.
- Program Backup: Program backup refers to the process of saving a copy of a ladder logic program to a computer or other storage device for safekeeping.
- Program Compare: Program compare refers to the process of comparing two ladder logic programs to identify differences or changes.
- Program Control instruction: Program control instructions are used to control the flow of a program.
- Program Debugging: Program debugging refers to the process of identifying and correcting errors in a ladder logic program.
- Program Download: Program download refers to the process of transferring a ladder logic program from a computer to a PLC.
- Program Merge: Program merge refers to the process of combining two or more ladder logic programs into a single program.
- Program Restore: Program restore refers to the process of restoring a ladder logic program from a backup to a PLC.
- Program Testing: Program testing refers to the process of testing a ladder logic program to ensure that it is functioning correctly.
- Program Upload: Program upload refers to the process of transferring a ladder logic program from a PLC to a computer.
- Program Validation: Program validation refers to the process of verifying that a ladder logic program meets the requirements and specifications of the system or process it is controlling.
- Real-time: Real-time refers to systems or processes that operate in real-time, meaning they respond to events or changes as they occur, rather than with a delay.
- Recipe Management: Recipe management is the process of creating, storing, and managing sets of instructions for controlling industrial processes.
- Remote Diagnostics: Remote diagnostics is the ability to diagnose and troubleshoot problems remotely, using a computer or mobile device.
- Remote Maintenance: Remote maintenance is the ability to perform maintenance and troubleshoot problems remotely, using a computer or mobile device.
- Remote Monitoring: Remote monitoring is the ability to monitor and control industrial processes remotely, using a computer or mobile device.
- Remote Programming: Remote programming is the ability to program or modify PLC programs remotely, using a computer or mobile device.
- Return address: Return address is the label or instruction to which control is returned after a subroutine call.
- Return instruction: Return instruction is used to transfer control of the program back to the main program after a subroutine has been called.
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- Rung: A single rung is a single horizontal row in a ladder logic diagram. It represents a specific logic function or operation.
- Safety PLC: Safety PLC is a type of PLC that is designed specifically for safety-critical applications, such as emergency shutdowns or safety interlocks.
- SCADA (Supervisory Control and Data Acquisition): SCADA is a type of industrial control system that is used to monitor and control industrial processes.
- Sequential Function Chart: Sequential Function Chart (SFC) is a graphical programming language that is used to program PLCs. It is similar to ladder logic, but it is more structured and allows for more advanced control and data manipulation.
- Shift instruction: Shift instruction is used to shift the bit values of a word or integer.
- Simulation: Simulation is the process of modeling the behavior of a system using a computer program.
- Soft PLC: Soft PLC is a software-based PLC that runs on a computer and simulates the behavior of a physical PLC.
- State Logic: State logic is a method of programming PLCs that uses a state machine to control the flow of the program.
- State Machine: A state machine is a model of computation that describes the behavior of a system as a sequence of states, transitions, and actions.
- String Manipulation: String manipulation instructions are used to manipulate strings of characters, such as concatenation, extraction, and comparison.
- Structured Text: Structured text is a high-level programming language that is used to program PLCs. It is similar to other high-level programming languages such as C or C++ and allows for advanced control and data manipulation.
- Subroutine call level: Subroutine call level refers to the current level of nested subroutine calls.
- Subroutine: Subroutine instructions are used to group related instructions together, making the program more organized and easier to read and troubleshoot.
- Time base: Time base refers to the time interval over which a timer instruction counts. It can be set to milliseconds, seconds, minutes, or hours.
- Time-out: Time-out refers to the time period after which a timer instruction will trip.
- Timer: Timer instructions are used to measure the time between the opening or closing of a contact.
- Trending: Trending is the process of plotting data over time to identify patterns and trends.
- Virtual HMI: Virtual HMI is a software-based HMI that simulates the appearance and behavior of a physical HMI.
- Virtual PLC: Virtual PLC is a software-based PLC that runs on a computer and simulates the behavior of a physical PLC.
- Visualization: visualization is the process of representing data graphically to make it easier to understand and interpret.
Please note that this is not an exhaustive list of Ladder Logic terms and definitions, and the specific terms and functions used in a Ladder Logic program may vary depending on the particular application and the manufacturer of the PLC. Depending on the specific context and application, many more terms and concepts could be used in Ladder Logic programming.