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:
Jan. 21, 1986
Filed:
Jun. 29, 1982
Avery W Powers, Scottsdale, AZ (US);
Guy L Cates, Mesa, AZ (US);
Charles W Staats, Jr, Tempe, AZ (US);
Jarrell W Mullies, Tempe, AZ (US);
Solid State Devices, Inc., Tempe, AZ (US);
Abstract
Apparatus and method for a circuit which is connected in series between the call signal output of a vehicle detector and the call signal input of a traffic controller is disclosed. Under normal operating conditions the invention acts as a signal buffer and input of the invention will be applied to the input of the traffic controller when call signal inputs are continuously present or not present for preestablished times, then test procedures are implemented. During a test or failure condition of the vehicle detector, the detector output signal will be disconnected from the controller. The invention also provides a circuit which is connected between the loop and the loop input of the vehicle detector. The circuit along with the accompanying method is designed to modify the input impedance to the vehicle detector to apply a test or 'forced' call signal to the vehicle detector input when a call signal input is not received after a predetermined period of time, a fault condition is established. Indicators display the operating states of the call signal output to the controller and/or the fault mode of the vehicle detector in the event of a fault condition. Apparatus is available for providing a synthetic call signal for use in controlling traffic in the event of selected apparatus failures.