Allen-bradley Company, LLC

Theodore J Markley

Odo J Struger

Daniel J Galdun

Robert G Henderson

Charles E Clark

Frank W Jencen

Ernst H Dummermuth

Donald E Taylor

William W Searcy

James F Burns

Lawrence W DeLong

Walter V Casto

William B Springer

A CRT terminal includes a main unit which houses circuitry and the CRT display. An application module which includes a keyboard plugs into the front of the main unit and electrically connects to its circuitry. A flexible membrane keyboard is employed which includes a keyboard overlay that is easily changed to provide keyboard symbols appropriate to a wide variety of different applications. Resilient bumpers extend completely around the main unit to facilitate its use in industrial applications where physical abuse is common.

Industrial terminal with elastic bumpers

Terminal with interchangeable application module

A program protection module for a programmable controller checks the critical, or protected, portion of the control program each time the controller is switched to the run mode. This is accomplished by reading each control program instruction out of the controller memory and comparing it with a corresponding control instruction stored in a nonaccessible read-only memory. If all the compared control instructions are identical, the module sets a status bit in the programmable controller which enables the protected portion of the control program to be executed. If identity is not found, an alarm is generated and the protected program is not executed.

Program protection module for programmable controller

A programmable controller includes four remotely located input/output interface racks which are connected by cables to an I/O scanner circuit which is centrally located with the controller processor and memory. Input and output data is serially transmitted between the I/O scanner circuit and the interface racks, and fault processors are located in both the I/O scanner circuit and the interface racks to monitor the operation. The fault processors include fault tolerant detector circuits which ignore erroneous transmissions caused by industrial noise, but which initiate a shutdown process when malfunctions occur. The shutdown process is controlled by a programmable disabling circuit which is responsive to program instructions stored in the controller memory to allow independent, quasi-independent, or dependent operation of the machines connected to each of the four interface racks.

Fault processor for programmable controller with remote I/O interface

A set of circuit boards are mounted side by side and electrical connection is made to terminal pads disposed along one edge of each circuit board by connectors which are carried by swing arms. The swing arms rotatably mount to a wire duct and each pivots between a horizontal position and an upright operating position in which connection is made to the terminal pads on its associated circuit board. Wire terminals on the connector in each swing arm provide termination for wires in the wire duct.

Disconnect arm for electrical equipment

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Mentor, OH, United States of America

Theodore J Markley