Stored program digital process controller

• US 4,001,557 A
• Filed: 10/14/1975
• Issued: 01/04/1977
• Est. Priority Date: 10/14/1975
• Status: Expired due to Term

• Current Assignee: The United States of America as represented by the United States Energy Research and Development Administration
• Original Assignee: The United States of America as represented by the United States Energy Research and Development Administration
• Inventors: Stephenson, Dwight L.
• Primary Examiner(s): Ruggiero, Joseph F.
• Application Number:
  US05/621,894
• Time in Patent Office: 448 Days
• Field of Search: 235/151.1, 235/151, 235/152, 235/156, 235/150.53, 340/172.5, 236/46 R, 236/46 A, 236/15 R, 236/15 B, 425/143, 264/40, 266/5 T, 432/51
• US Class Current: 700/14
• CPC Class Codes: G05B 19/045 using logic state machines, consisting only of a memory or a programmable logic device containing the logic for the controlled machine and in which the state of its outputs is dependent on the state of its inputs or part of its own output states, e.g. binary decision controllers, finite state controllers
• CPC Class Codes: G05B 19/07 where the programme is defined in the fixed connection of electrical elements, e.g. potentiometers, counters, transistors
• CPC Class Codes: G05B 19/075 for delivering a step function, a slope or a continuous function G05B19/06 takes precedence

Abstract

A digital process control function generator wherein a timing clock, in conjunction with programmable read only memories controls variables in a process with respect to time.

Claims

1. Digital process controlling apparatus comprising:

a clock generator;

a dwell time code generator connected to said clock generator for providing a plurality of pulse frequencies;

dwell time select decoder connected to said dwell time code generator selecting desired pulse frequencies;

2. memory address counter means in circuit with said dwell time select decoder for converting said pulse frequencies to memory addresses;

a first programmable read only memory having an input from said memory address counter and an output to said dwell time select decoder for setting dwell times corresponding to memory addresses;

a second programmable read only memory having an input from said memory address counter having process variables stored therein at addresses coinciding with the corresponding dwell times stored in said first programmable read only memory;

process control means connected to the output of said second programmable read only memory; and

,

an auxiliary process control relay connected to the output of said first programmable read only memory.