0490864-A1 is referenced by 29 patents and cites 4 patents.

A controller of the type used in process control includes a plurality of modular I/O units. The I/O units includes I/O circuits which may be of four basic types: digital input circuits, digital output circuit, analog input circuits and analog output circuits. Each of the I/O circuits has a code generator that generates a binary code indicating the type of I/O circuit. The controller is microprocessor-controlled and periodically communicates with the I/O circuits and determines the type of each I/O unit based upon the binary code. The I/O units may be temperature-compensated based upon the temperature within the housing of the controller, and other integrity checks may be performed on the I/O units. The controller also has a change module routine which allows the I/O units to be installed or removed during operation of the controller.

Title
Process controller with modular i/o units.
Application Number
EP19910870201 19911209
Publication Number
0490864 (A1)
Application Date
December 9, 1991
Publication Date
June 17, 1992
Inventor
Vanderah Richard Joseph
US
Sickels Dennis Gene
US
Milliken Jon Barry
US
Assignee
Fisher Controls Int
US
IPC
G05B 19/04
G05B 19/04
G05B 15/02
G05B 19/042
G05B 15/02
View Original Source Download PDF