Allen-Bradley Company, LLC

Ronald A Brown

Odo J Struger

Daniel J Galdun

Valdis Grants

Craig A Black

Sung C Hu

An interchangeable keyboard application module is connected to a video monitor module in a computer terminal to provide sequences of processor instructions and a keyboard for performing a plurality of selectable applications. The video monitor module includes a CRT display, a serial I/O interface and a processor that processes characters received through the serial I/O interface for display on the CRT screen whether or not the application module is attached. The processor in the video monitor module detects the connection of the application module, and then selects its instructions from a memory in the application module first, to prompt the selection of a mode of operation for the terminal, and second to execute the selected mode of operation. The application module uses a plurality of keyboard overlays, each corresponding to a respective mode of operation. In a specific embodiment two of the modes of operation are programming applications related to programmable controllers.

Video computer terminal with detachable intelligent keyboard module

A preferred embodiment of an input module is connected through six address terminals and four data terminals to six banks of contacts. A single bank address is coupled to two latches in the module and then to two banks of contacts. A nibble of data is coupled from each of two banks of contacts to each of two corresponding data latches on the module. The sequential addressing of a low nibble bank and a high nibble bank and the latching of data therefrom is controlled by sequencing circuitry which is enabled each time a bank address is written to the module. In a second embodiment coded information is output through the six address terminals and decoded by two external decoders to multiplex 256 inputs to the processor. Such modules are particularly useful in multiplexing a large number of inputs to the processor of a programmable controller.

Multiplexing I/O module

A programmable controller has a high density I/O module for interfacing eight analog input devices to a main processor module. The high density I/O module has a microcomputer for reading, storing and updating eight words of input data. The microcomputer also communicates with the main processor of the main processor module to transfer the eight words of input status data to a main memory. The main processor is programmed to communicate with the microcomputer in two alternate modes. In one mode the main processor is directed by an applications control program to individually couple words of the status data; in the other mode the main processor is directed by firmware instructions to alter the input/output scan and couple a block of input data.

Programmable controller with high density intelligent I/O interface

A small, low-cost programmable controller is programmed with both bit-oriented and word oriented program instructions that are stored in a main memory. A microprocessor couples each program instruction to a respective interpreter routine of machine instructions stored in an interpreter memory. Bit-oriented program instructions with a common operation code but different bit-pointer codes are coupled to their own respective interpreter routines. The program instructions have operation codes and bit pointer codes that are assigned by a program panel, and are then translated by a translator PROM as they are coupled to an interpreter routine. Operand addresses are read through the translator PROM unchanged. Error-locating circuitry assists in detecting faulty chips in the main memory as the control program is executed. The hardware required to execute the control program is minimized, while the translator PROM allows the processor unit to be used with prior program panels.

Growing community of inventors

Willowick, OH, United States of America

Ronald A Brown