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Data Move Function Overview
The data move function is used to transfer data from one location to another within the PLC. It is a fundamental operation in PLC programming, allowing for the manipulation and routing of data throughout the control system. The move function typically takes a source value and moves it to a destination address, which can be a memory location, an output, or another variable. This function is essential for tasks such as updating values, controlling outputs based on input conditions, facilitating communication between different parts of the program and controlling sequential operations.
Using a Move Function
Move functions are used in many different scenarios, such as:
- Transferring sensor readings to a display or HMI.
- Updating the value of a timer or counter.
- Controlling outputs based on input conditions.
- Facilitating communication between different parts of the program.
- Controlling sequential operations in a process.
Primarily we use move functions for integer sequential control, they are used alongside comparators to activate individual steps inside a sequence. For example, if we have a multi-step process and we want to move from step 1 to step 2 when a certain condition is met, we can use a move function to transfer the value representing the current step to the next step in the sequence.
The move function also allows us to simplify repetitive code. For instance, if we have a process that requires the same operation to be performed but for varying amounts of time or under different conditions, we can use a move function to update the parameters of that operation without needing to rewrite the logic for each case.
Each mode rung contains its own MOVE instruction. The active mode writes a different preset value into T1.PRE. The timer itself is on a separate rung, and the output only energises when T1.DN becomes true.