Abstract: A plant loop communication system utilizing a plurality of Loop Interface Slave (LIS) modules, each of which being an intelligent slave module incorporating its own microprocessor, is described. The use of such a module permits off-load processing so that receiving, transmitting and message processing cam occur simultaneously. A Superloop Bus Module (SBM) contains a data base which allows the asynchronous operation of the system. A Superloop Storage Module (SSM) stores data for transmission onto the loop and/or incoming data for transmission to an operator console.

Abstract: A display system for displaying select dynamic process data of plant operations to an operator providing a display of only dynamic data having a predetermined difference between current and stored values.

Abstract: A system for processing and selectively transmitting process signals to a computer and/or a display device is disclosed. The system utilizes a binary full adder (38) to add the incoming signal, in inverted form, to the previously transmitted signal to obtain the difference therebetween. A binary comparator (52) compares the difference with a predetermined value, established by thumbwheel switches (46), and if the difference exceeds the predetermined level, causes the actuation of a flip-flop (54) and a bistable latch (32) permitting the incoming signal to be transmitted to a computer and/or a display device.