Allen-Bradley Company, LLC

David R Rohn

Raymond R Husted

Charles Martin Rischar

Ronald Edwin Schultz

Otomar S Schmidt

Wayne C Van Sickle

Terrence L Dauterman

David Allen Johnston

Raymond A Grudowski

Michael S Pelley

Lawrence A Komarek

Terry L Dauterman

An industrial controller executing a graphical language employs a comparator circuit for monitoring the address locations of memory used to store the control program and its data. A cursor positioned on a graphics representation of the program is used to identify a particular graphical element to be monitored and the address of the starting instruction for that element is loaded into the comparator. An interrupt generated by the comparator causes the generation of a histogram listing the particular rungs name and the times at which it has been executed, useful for verifying and monitoring the operation of a control program. A snapshot of data values used by the element of the program at the time of its execution may also be stored to verify the condition under which the element executes.

Industrial controller with display of rung execution

A multitasking industrial controller for real-time control of machinery and the like permits the use of both periodic and event driven tasks by establishing a hierarchy of both task types in the form of priorities that resolve conflicts between events of the same and different types. The unpredictability of the event driven tasks on scheduling of tasks is addressed by watchdog time values assigned to each task which confirm timely execution of the task in practice despite the risk of preemption by other tasks. Flexible software definition of event driven tasks is made possible by delegating the detection of the events to input/output modules executing independently of the processor executing the operating system.

Multitasking industrial controller

A programmable controller has a rack that electrically connects a number of I/O modules to a processor module. The processor module includes a external device communication interface section and a general purpose processor section electrically coupled together by a set of common buses. Both of these module sections include a microprocessor and memory connected by an internal set of buses which are isolatable from the set of common buses. The isolation capability permits the different sections to perform their operations simultaneously. A shared system memory and an rack interface are coupled to the common buses for the exchange of data with the I/O modules. A unique ladder logic processor also is connected directly to the common buses. The ladder logic processor includes a hardwired Boolean bit logic processor and a custom microcoded processor to execute instructions of a ladder type control program. Program instructions which are too complex for execution by the ladder logic processor are executed by the general purpose processor section.

Processor for a programmable controller

Programmable controller processor module having multiple program

A programmable controller stores a user control program which is comprised of a plurality of conventional ladder programs and a structure chart program. A microprocessor executes a structure chart interpreter routine to interpret the structure chart program and to thereby create an active state list which indicates the ladder programs that are to be executed. The same microprocessor with the assistance of a bit processor also executes the ladder programs which are indicated on the active state list to control a machine connected to the programmable controller.

Programmable controller with function chart interpreter

A programmable controller includes a memory which stores an I/O image table and a data table. An I/O scanner module updates the I/O image table with the status of I/O devices connected to the programmable controller. The processor executes a control program to perform logical and arithmetic operations on the data in the data table. Such operations may be performed on data of different types and any necessary data conversions are performed automatically. Also, such operations may be performed on entire data files without degrading the response time of the programmable controller.

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Richmond Heights, OH, United States of America

David R Rohn