The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 03, 1978
Filed:
Jun. 06, 1977
Walter V Casto, Solon, OH (US);
Lawrence W DeLong, Stow, OH (US);
Theodore J Markley, Mentor, OH (US);
Odo J Struger, Chagrin Falls, OH (US);
Allen-Bradley Company, Milwaukee, WI (US);
Abstract
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.