Abstract: An FPGA clock signal self-detection method relates to the technical field of control module, and the technical problem to be solved is to improve operational reliability and safety of the FPGA chip. The method comprises introducing two clock signals to an FPGA chip, wherein one clock signal is a first clock signal, and the other clock signal is a second clock signal; using the first clock signal to control all synchronous logic operations in the FPGA chip, and using the second clock signal to detect the first clock signal for correctness. The method of the invention is particularly applicable to a system with the FPGA chip as a main controller or important control unit.

Abstract: This invention relates to a combined ring rolling method for spherical valve body, which has the following procedures: 1) design for ring blank by computing ring blank volume and selecting reasonable rolling ratio according to the dimensions of forged ring; 2) design for rolling gap which includes the shapes and dimensions of working surfaces of main roll, mandrel and passive rolls according to the dimensions of ring blank and forged ring, the stable deformation condition of combined ring rolling and structure requirement of rolling equipment; 3) rolling forming with three stages of surface cross rolling, ring rolling and shaping by controlling of feeding speed of main roll and working positions of passive rolls. This invention has the technical economical advantages of low consumptions of energy and materials, high productivity and low production cost.

Abstract: Exemplary embodiments of the present invention are directed to methods and devices for detecting open-circuit and short-circuit failure in an electromagnetic (inductive) measurement of the conductivity of liquids and on the sensor and cable wiring. An electromagnetic measurement of the conductivity of a liquid is performed by immersing a sensor into the liquid, wherein the sensor includes at least 2 toroidal cores, one of them carrying an excitation coil and the other carrying an induction coil. When an AC excitation voltage is applied to the excitation coil, an induced current or voltage can be measured in the induction coil which is proportional to the conductivity of the measured liquid.

Abstract: Exemplary embodiments of the present invention include methods and devices for the electromagnetic (inductive) measurement of the conductivity of liquids by immersing a sensor into the liquid, wherein the sensor includes at least 2 toroidal cores, one of said cores carrying an excitation coil and the other core carrying an induction coil. Exemplary methods include converting the induced current at the induction coil into an alternating square-wave voltage, followed by rectification. A sample-hold circuit may be employed to avoid the transition time of the alternating square-wave current conversion. The demodulated DC voltage is proportional to the conductivity of the measured liquid.

Abstract: Exemplary embodiments of the present invention are directed to methods and devices for detecting open-circuit and short-circuit failure in an electromagnetic (inductive) measurement of the conductivity of liquids and on the sensor and cable wiring. An electromagnetic measurement of the conductivity of a liquid is performed by immersing a sensor into the liquid, wherein the sensor includes at least 2 toroidal cores, one of them carrying an excitation coil and the other carrying an induction coil. When an AC excitation voltage is applied to the excitation coil, an induced current or voltage can be measured in the induction coil which is proportional to the conductivity of the measured liquid.

Abstract: Exemplary embodiments of the present invention include methods and devices for the electromagnetic (inductive) measurement of the conductivity of liquids by immersing a sensor into the liquid, wherein the sensor includes at least 2 toroidal cores, one of said cores carrying an excitation coil and the other core carrying an induction coil. Exemplary methods include converting the induced current at the induction coil into an alternating square-wave voltage, followed by rectification. A sample-hold circuit may be employed to avoid the transition time of the alternating square-wave current conversion. The demodulated DC voltage is proportional to the conductivity of the measured liquid.