Load control error detector

Claim 2

In a load control system having at least one energizable load; switching means activatable by a control signal for coupling said load with an alternating current voltage source for energizing said load; and load control means for providing said control signal; the improvement comprising: means for providing an error signal in response to a condition wherein said load is energized in the absence of a said control signal applied to said switching means. means for providing an alarm indication and a delay device for energizing said alarm indication means a predetermined interval of time after occurrence of an error signal.

Claim 3

In a load control system having an energizable load with a load terminal, switching means having a power supply terminal and a control signal terminal for a coupling said load terminal to the power supply terminal upon application of a control signal to the control signal terminal and load control means for providing such a control signal, the improvement comprising: means for providing an error signal in response to a condition wherein said load is energized in the absence of a control signal applied to said control signal terminal, said error signal means comprising a current storage device coupled to said load terminal having an output terminal for providing an error signal when energized and a short circuiting device connected to said terminal with a control element connected to said control signal terminal for short circuiting said current storage device upon the occurrence of a control signal, whereby an error signal is produced only upon the occurrence of energy at said load terminal without the occurrence of a control signal at said control signal terminal.

Claim 4

In a load control system having an energizable load with a load terminal, switching means having a power supply terminal and a control signal terminal for a coupling said load terminal to the power supply terminal upon application of a control signal to the control signal terminal and load control means for providing such a control signal, the improvement comprising: means for providing an error signal in response to a condition wherein said load is energized in the absence of a control signal applied to said control signal terminal, said error signal means comprising a current storage device coupled to said load terminal having an output terminal for providing an error signal when energized and a short circuiting device connected to said terminal with a control element connected to said control signal terminal for short circuiting said current storage device upon the occurrence of a control signal, whereby an error signal is produced only upon the occurrence of energy at said load terminal without the occurrence of a control signal at said control signal terminal.

Claim 5

In a load control system as set forth in claim 1, the improvement wherein said alarm indication means includes a visual display.

Claim 6

In a load control system having an energizable load, switching means activatable by a control signal for coupling said load with an alternating-current voltage source for energizing said load; and load control means for providing said control signal; the improvement comprising: means for providing an error signal in response to a condition wherein said load is energized in the absence of a control signal applied to said switching means, said error signal means including a first input interposed between said switching means and said load for receiving alternating current from said voltage source, a second input for receiving a said control signal, and circuit means having an output circuit and being interposed between said inputs for providing an error signal which is carried by said output circuit when said alternating current is not concurrently received with a said control signal.

Claim 7

In a load control system having an energizable load, switching means activatable by a control signal for coupling said load with an alternating-current voltage source for energizing said load; and load control means for providing said control signal; the improvement comprising: means for providing an error signal in response to a condition wherein said load is energized in the absence of a control signal applied to said switching means, said error signal means including a first input interposed between said switching means and said load for receiving alternating current from said voltage source, a second input for receiving a said control signal, and circuit means having an output circuit and being interposed between said inputs for providing an error signal which is carried by said output circuit when said alternating current is not concurrently received with a said control signal.

Claim 8

In a load control system as set forth in claim 4, the improvement wherein said circuit Means further includes a storage capacitor having one end coupled to said output circuit and its other end coupled to a reference potential, rectifying means interposed between said one end of said capacitor and said first input for applying rectified current from said alternating current to said capacitor, and means controlled by a said control signal for short circuiting said capacitor during the period a said control signal is received, whereby upon removal of said control signal said capacitor becomes charged by said alternating current so that an error signal is carried by said output circuit.

Claim 9

In a traffic control system having at least one traffic signal light for, upon energization, displaying a traffic signal indication; switching means, activatable by a control signal for coupling said signal light with an alternating current voltage source for energizing said signal light; and traffic signal control means for providing said control signal, the improvement comprising: an error detector circuit having an output circuit for generating an error signal, a first input circuit interposed between said switching means and said traffic signal light for receiving alternating current from said voltage source, a second input circuit for receiving a said control signal and circuit means interposed between said input circuits for providing an error signal on said output circuit so long as said alternating current signal is received without concurrent reception of a said control signal.

Claim 10

In a traffic control system having at least one traffic signal light for, upon energization, displaying a traffic signal indication; switching means, activatable by a control signal for coupling said signal light with an alternating current voltage source for energizing said signal light; and traffic signal control means for providing said control signal, the improvement comprising: an error detector circuit having an output circuit for generating an error signal, a first input circuit interposed between said switching means and said traffic signal light for receiving alternating current from said voltage source, a second input circuit for receiving a said control signal and circuit means interposed between said input circuits for providing an error signal on said output circuit so long as said alternating current signal is received without concurrent reception of a said control signal.