US 5,327,123 A · Traffic control system failure monitoring

Abstract

A traffic control system for use at a roadway intersection, the system including traffic control lights, a light flasher structure, and a plurality of load switches electrically coupled with the lights via relay structure to which the flasher structure is connected, the load switches having inputs, and a controller connected with the load switches for controlling normal operation of the lights and flashing of one or more of the lights by the flasher structure in the event of a system malfunction comprising a microprocessor operatively connected with the load switches, flasher, and relay structure to monitor the system for detecting a malfunction event, for recording the detected malfunction event, and for transmitting the malfunction detection to another location; and verification structure at the other locations for i) receiving the transmitted malfunction detection, ii) verifying the event, and iii) initiating malfunction corrective action; whereby the corrective action in the system may be initiated without removing control by the controller of the operation of the traffic control lights at the intersection.

Claims19

Dependent claims

In a traffic control system for use at a roadway intersection, the system including traffic control lights, a light flasher means for effecting light flashing, relay means for electrical coupling, and a plurality of load switches electrically coupled with said lights via said relay means to which said light flasher means is connected, said load switches having inputs, and a controller connected with said load switches for controlling normal operation of said lights and flashing of one or more of said lights by said light flasher means in the event of a system malfunction, the combination comprising

a) a microprocessor operatively connected with the said load switches, said light flasher means, and said relay means to monitor the system for detecting a malfunction event, for recording the detected malfunction event, and for transmitting the detected malfunction event to another location,
b) and verification means at said other location for
i) receiving said transmitted malfunction detection,
ii) verifying said event, and
iii) initiating malfunction corrective action,
c) whereby said corrective action in said system may be initiated without removing control by the controller of said operation of the traffic control lights at said intersection.

3 more elements

In a traffic control system for use at a road intersection, the system including traffic control lights, a light flasher means for effecting light flashing, relay means for electrical coupling, and a plurality of load switches having output sides electrically coupled with the lights via said relay means to which said light flasher means is also connected, and a controller connected with said load switches for controlling normal operation of said lights and flashing of one or more of said lights by said light flasher means in the event of a system malfunction, the combination comprising

a) a signal monitor means coupled to said light flasher means via said relay means, and also coupled to said load switches, whereby the signal monitor monitors voltage at said output sides of the load switches,
b) each load switch having three DC inputs, three corresponding outputs, one output being turned ON in response to application of a DC ground to the corresponding DC input,
c) a voltage summing circuit coupled to the input of each load switch, said circuit including three interconnected resistors respectively in series with said DC inputs, and said circuit coupled to said signal monitor means,
d) the voltage summing circuit including three diodes respectively connected in series with the three resistors to prevent the DC inputs from feeding energy to the signal monitor means when said inputs are in off-state,
e) the signal monitor means including an additional resistor coupled to a stable reference voltage,
f) said additional resistor and the three resistors in said voltage summing circuit forming a voltage divider when a DC output from the load switch is selected by the controller, to allow determination of which DC input is ON, at a particular load switch.

3 more elements

Dependencies are inferred from the claim text.

Traffic control system failure monitoring

Life of this patent

Traffic control system failure monitoring

Life of this patent

Abstract

Claims19