The magnetic coil driving circuit of the magnetic contactor according to the present invention comprises a semiconductor switch configured to open or close a circuit for magnetizing or demagnetizing a magnetic coil; a pulse width modulation unit configured to output a pulse signal as a control signal for turning on or off the semiconductor switch; a control unit configured to output a control signal for changing a pulse width of the pulse signal to the pulse width modulation unit; and a temperature detection and protection unit configured to detect a temperature inside the magnetic contactor, output an output signal for turning off the semiconductor switch when the temperature exceeds an allowable temperature, and control the semiconductor switch by the pulse signal from the pulse width modulation unit when the temperature is within the allowable temperature.

A control apparatus for controlling a linear solenoid by controlling a driving current supplied to the linear solenoid through a feedback control. The feedback control is executed by a feedback control system having parameters that are determined in accordance with an ILQ design method. In a frequency characteristic of a gain of a transfer function representing a ratio of an output to a disturbance in the feedback control system, the gain is lower than 0 [dB] throughout all frequency ranges.

A method for controlling an electromagnetic actuator including: applying a first control strategy in which first and third switches are kept in a closed state, whereas a second switch is switched between its open and closed states; detecting an occurrence of overconsumption of current in a coil of the actuator, by detecting that voltage measured on a control bus has exceeded a predefined voltage limit or by detecting that a duty cycle of the second switch has dropped below a threshold value; and in response, applying a second control strategy, instead of the first control strategy, in which the third switch is periodically opened in order to decrease the current supplied to the coil.

A solenoid plunger movement detection system and method can include: detecting current supplied to a solenoid with a current sensor; converting the current supplied to the solenoid into a digital signal with a counter coupled to a first comparator; detecting a peak within the digital signal with a peak detector; comparing the peak to the digital signal with a second comparator coupled to the peak detector; measuring a dip from the peak and measuring a trough with the second comparator; generating a fault when the peak and the trough indicate a smooth current ramp to the solenoid; receiving configurable parameters for processing the digital signal with a signal processor; and providing configurable parameters to the counter, the second comparator, the signal processor, or a combination thereof with an interface.

A method is for operating a valve that includes a linearly movable control slide, at least one solenoid, and a position sensor. The linearly movable control slide is preloaded by at least one spring in a direction of a zero position. The at least one solenoid is coupled to the control slide in such a way that the control slide can be moved away from the zero position by application of current to the solenoid. The position sensor is configured to measure an actual instantaneous position of the control slide. Each solenoid is assigned a current control device configured to influence a current through the relevant solenoid based on an instantaneous current control variable. The instantaneous current control variable is dependent on a quasi-periodic dither current control variable. The method also includes calculating an actual dither amplitude from the actual instantaneous position using a band-pass filter.

A fluid dispensing device and method for controlling the device are provided. The device includes a housing defining a fluid outlet. A valve controls the flow of fluid to the outlet. A sensor is configured to detect an object outside of and proximate to the housing. A solenoid is configured to move the valve between an open position and a closed position. A controller is configured to receive the output signal of the sensor, determine a characteristic of noise in the output signal such as a level of noise, adjust at least one of a sampling rate of the output signal and an amount of filtering of the output signal responsive to the characteristic of noise in the output signal, and transmit a control signal to the solenoid responsive to the output signal.

A method checks the plausibility of a measurement of an actuator current by use of an actuator two-terminal network. The actuator two-terminal network contains an inductive load and a resistive load. A first pole of the actuator two-terminal network is connected to a supply voltage via a pulse-width-modulated switch and is connected to earth via a freewheeling diode arranged in the reverse direction, and wherein a second pole of the actuator two-terminal network is connected to earth.

Provided are embodiments for operating an autonomous mode change circuit for solenoid drivers. The embodiments include initiating an operation of a solenoid, and receiving a command to control the operation of the solenoid. The embodiments also include controlling, by a drive circuit, a switch coupled to the solenoid based at least in part on the command, and detecting at least one of a current or voltage of the solenoid, and subsequently controlling the operation of the solenoid based at least in part on the detection.

A sprayer control system includes a plurality of smart nozzles each having at least one control valve with a valve operator, an electronic control unit for the valve operator, and one or more spray nozzles. The at least one control valve and the ECU control a flow rate of liquid agricultural product through the nozzles. A duty cycle modulator is in communication with the ECU and generates an applied duty cycle for the at least one control valve. The duty cycle modulator includes a specified duty cycle input having a specified duty cycle and a pressure monitor associated with the at least one control valve. A pressure comparator compares the valve pressure determined with the pressure monitor with a system pressure and generates a pressure error. An applied duty cycle generator generates the applied duty cycle based on the specified duty cycle modified by the pressure error.

A controller for a linear solenoid valve is configured to: calculate an average value of an exciting current within a period including a natural number multiple of the dither cycle as an average current value; execute a feedback control on a control value of the pulse width modulation signal such that a target value of the exciting current and the average current value match; and calculate a dither correction amount by multiplying a ratio between the control value of the pulse width modulation signal obtained by the feedback control and the average current value by a dither current value that is a current value corresponding to the dither correction amount and calculating the dither correction amount such that an increase in the exciting current due to the dither correction amount is canceled out by a decrease in the exciting current due to the dither correction amount within one dither cycle.