Diagnostic aid for industrial controller using multi-tasking architecture
AssigneeAllen-Bradley Company, Inc.
InventorsDavid Johnston, Charles M. Rischar, Jennifer McDonel
Life of this patent
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Abstract
A task executed on a multi-tasking industrial controller is employed to monitor data exchanged between a control program (executed as a second task on the industrial controller) and the controlled process. The monitoring task, which may be invoked on a periodic basis, reads designated data, compares it to its last value and if it changes, stores the value in a buffer. A separate program reads this buffer and displays relevant information to the user minimizing degradation in the performance of the control program and eliminating the possibility of corruption of the control program as would be required for the introduction of special memory trapping instructions into the control program.
Claims12
A method of displaying the real-time status of input/output data exchanged between a multi-tasking industrial controller executing a control program and a control process, the method comprising the steps of:
- (a) executing the control program as first of at least two concurrent tasks on the multi-tasking industrial controller;
- (b) accepting an input from a user identifying an input/output datum referenced by the control program;
- (c) identifying a memory location in the industrial holding the input/output data;
- (d) generating a memory monitor program to be run as a second of at least two concurrent tasks on the multi-tasking industrial controller, the memory monitor program receiving the memory location identified in step (c) and monitoring the memory location to record the time of a change in the data in the memory location;
- (e) executing the memory monitor program concurrently with the control program;
- and
- (f) displaying the recorded time of change.
Dependencies are inferred from the claim text.