Programmable logic controller
AssigneeNyquist BV
InventorAbraham J. A. M. Jansen
Life of this patent
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Abstract
In a programmable logic controller data is exchanged between a data communication section and a sequential control section. Within the sequential control section a communication task is activated for a given period during each PLC cycle. Subsequently, inter alia a user task is activated; this user task controls a machine or a process inter alia on the basis of the data exchanged. By making the ratio of the period in which the communication task is active to that in which the user task is active adjustable, very time-critical processes with a very short response time can be controlled as well as large amounts of data can be exchanged in few PLC cycles during less time-critical phases of operation of the machine or process to be controlled.
Claims16
A programmable logic controller (PLC), comprising a processor comprising a sequential control processor unit and a data communication processor unit for communicating with at least one external system, said PLC arranged to execute tasks cyclically during sequential control, in each cycle a given period of time available to each task, said tasks comprising a user task for executing an application program and a communication task for exchanging, via a memory data between the sequential control processor unit and the data communication processor unit, the ratio of the durations of the periods available to the execution of the communication task and the application program adjustable during the execution of the application program based on data supplied to the sequential control processor unit in executing the communication task.
Apparatus comprising a central processing unit, said central processing unit comprising a sequential control processor for sequentially executing tasks and a data communication processor for communicating with at least one external system, said tasks executed by said sequential control processor comprising a user task for executing an application program and a communication task for exchanging, via a memory, data between said sequential control processor unit and said data communication processor unit, a ratio of a time period available for execution of said communication task and an application program adjustable based on data supplied to said sequential control processor in executing said communication task.
Apparatus comprising a central processing unit, said central processing unit comprising a sequential control processor for sequentially executing tasks and a data communication processor for communicating with at least one external system, said tasks executed by said sequential control processor comprising a user task for executing an application program and a communication task for exchanging, via a communication unit, a predesignated period of time allocated for execution of each of said tasks, data between said sequential control processor unit and said data communication processor unit, a ratio of a time period available for execution of said communication task and an application program adjustable based on data supplied to said sequential control processor in executing said communication task, said apparatus further comprising a look-up table designating an amount of time allocated for execution of a command.
Dependencies are inferred from the claim text.