Multiplexed automatic control system
First Claim
1. A control system for controlling at least one actuator having a relatively low impedance at low frequencies comprising:
- a source of energy of relatively low frequency for energizing the actuator;
a pair of leads connecting the source of energy to the actuator;
a sensor having a relatively high impedance at low frequencies connected to the leads;
an oscillator for generating a sensing signal of relatively high frequency, and means coupling the high frequency signal from said oscillator to said leads to be supplied to said sensor over said leads;
switching means connected to at least one of said leads for controlling the energization of the actuator by the energy from said source; and
control circuitry connected to said leads and responsive to said high frequency sensing signal flowing in the leads and through the sensor for operating said switching means to energize the actuator when the impedance of said sensor means reaches a predetermined value.
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Accused Products
Abstract
A control system and circuit for use with one or more inductance-type actuators, such as solenoid controlled water sprinkler valves, having a relatively low impedance at low frequencies, which serves to operate the actuators, for example, when ground moisture falls below a preset level. A sensor having a relatively high impedance at low frequencies, and which for example may be moisture variable, is provided for each actuator. The control circuit is connected to the actuator over appropriate electric leads, and the same leads are used to connect the sensor back to the control circuit thereby obviating the need for extra wires and difficult retrofits.
28 Citations
11 Claims
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1. A control system for controlling at least one actuator having a relatively low impedance at low frequencies comprising:
- a source of energy of relatively low frequency for energizing the actuator;
a pair of leads connecting the source of energy to the actuator;
a sensor having a relatively high impedance at low frequencies connected to the leads;
an oscillator for generating a sensing signal of relatively high frequency, and means coupling the high frequency signal from said oscillator to said leads to be supplied to said sensor over said leads;
switching means connected to at least one of said leads for controlling the energization of the actuator by the energy from said source; and
control circuitry connected to said leads and responsive to said high frequency sensing signal flowing in the leads and through the sensor for operating said switching means to energize the actuator when the impedance of said sensor means reaches a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- a source of energy of relatively low frequency for energizing the actuator;
Specification