Patent ID: 7168075
Filing Date: 2007-01-23
Classification: G05B,G06F

Abstract:
1. A programmable controller for at least one of controlling and monitoring a process, connected to a redundant programmable controller having a memory, said programmable controller comprising: a memory to store at least one user program, having at least one task, and process related data and user-program-related data; a processor to execute said at least one task of the at least one user program and an updating task assigned thereto to transfer contents of a portion of said memory accessed by the at least one task into the memory of the redundant programmable controller and to terminate the updating task when a run time of the task and the updating task exceeds an upper run time limit; and a log memory, coupled to at least one of said memory and said processor, to log accesses of said memory by each task, wherein said processor executes the updating task to transfer the contents of the portion of said memory based on contents of said log memory logged for the task being updated, wherein the updating task is assigned a higher priority than the task to which the respective updating task is assigned, wherein if a cyclic updating task T wherein, if an error task for selected error processing or error responses has a priority lower than run time tasks T