Camozzi Automation S.p.a.

Andrea Camisani

Dario Ferrarini

A diagnostic method for solenoid valves includes detecting, at excitation of the solenoid, a variation rate of the supply voltage of the solenoid and comparing it with a predetermined value, generating an error signal if the variation rate is lower than the predetermined value, otherwise, detecting characteristics of the waveform of the solenoid current over a time interval between a moment of excitation of the solenoid and a moment wherein the movable core reaches end-stroke position, comparing the detected characteristics with threshold values, generating an alarm signal if the detected characteristics are lower than the threshold values, otherwise calculating the value of solenoid resistance and comparing it with a minimum resistance value and a maximum resistance value when the solenoid current is in steady state, and generating an alarm signal if the solenoid resistance value is lower than the minimum resistance value or greater than the maximum resistance value.

Diagnostic device and method for solenoid valves

A diagnostic method for diagnosing a malfunction of a solenoid valve includes: a) storing reference features of a solenoid current waveform, b) detecting features of the solenoid current waveform during operation of the solenoid valve, c) comparing the reference features with the detected features, d) comparing the pressure value of fluid entering the solenoid valve inlet orifice with a predetermined range of pressure values in the event of deviation between the value of the detected features and the value of the reference features, e) adjusting the pressure value and repeating steps b) and c) in the case of deviation of the pressure value with respect to the pressure value range, and f) generating an alarm signal due to malfunction of the solenoid valve in the event of a deviation between the value of the detected features and the value of the reference and fluid pressure features within the pressure value range.

A pressure regulator includes an outlet pressure sensor, loading and unloading electromagnetic valves, and a regulator control circuit operatively connected to the loading and unloading electromagnetic valves and configured to pilot the loading and unloading electromagnetic valves to cancel an error signal given by a difference between an inlet signal corresponding to a desired outlet pressure and a feedback signal provided by the outlet pressure sensor. The pressure regulator includes an engaging current analysis circuit to detect and store reference characteristics of the engaging current of the solenoid of the loading electromagnetic valve in a stable inlet pressure condition, monitor the engaging current to detect any variation of its characteristics with respect to the corresponding reference characteristics, and, in the event of variation, provide a pilot modulation signal to at least one of the loading or unloading electromagnetic valves or a pressure variation signal to the regulator control circuit.

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Brescia, Italy

Andrea Camisani