Upon completion, control returns to the task that was interrupted, at the point in which it was interrupted: Once initiated, all programs assigned to the event task are executed or scanned once from top to bottom. When triggered, the event task interrupts any lower priority tasks (other event, continuous, or periodic tasks). Each task is assigned a priority level. After this single scan, control is returned to the task that was interrupted.Īn event task is a task that performs a certain function only when triggered by a specified event: Once triggered, all programs assigned to the periodic task are executed or scanned once from top to bottom.
Task will interrupt any lower priority task (other periodic, continuous, or event tasks). Each task is assigned an execution rate. Upon completion of a single execution scan, a physical output update is triggered and the scan starts again:Ī periodic task is executed at a fixed interval: When executing, all programs assigned to that task are scanned once from top to bottom. By default, a continuous task has the lowest priority of any tasks. Task: A mechanism for scheduling and executing programs:Ī continuous task is a task that runs at all times unless it is interrupted by another task: Routine: A section of code (ladder logic, function block diagram, sequential function chart, structured text) written and executed as a group. Program: A group of related routines and data. Task: A mechanism for scheduling and executing programs. Offline: Viewing or editing a copy of a project file that is in the computer only.Ī communications path is required to upload, download, or go online.Ī project is organized using these components: Online: Viewing or editing a project file that is active in the controller: When you download a project file into a controller, all information except standard documentation is loaded into the controller:
Downloading overwrites the current roject file in the controller. This does not apply to structured text comments.ĭownload: Transfer a copy of a project file from a computer to a controller over a network:Ī controller can only contain one project file at a time. To access this type of documentation, a matching file must be found in the computer. Standard documentation, such as rung comments and operand descriptions, is not uploaded.
To create a permanent copy, the file must be saved to the hard drive of the computer. Uploading transfers the file in the controller into the temporary memory (RAM) of the computer. Upload: Transfer a copy of a project file from a controller to a computer over a network:
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