47results about How to "Avoid sampling error" patented technology

The invention discloses a current sampling circuit applied to a boost-buck circuit and a control method thereof. The boost-buck circuit comprises a reference field, a first MOS (Metal-Oxide-Semiconductor) transistor, a second MOS transistor, a third MOS transistor, a fourth MOS transistor and an inductor; the current sampling circuit comprises a first current sampling circuit, a second current sampling circuit and a current processing circuit; the first sampling circuit is used for sampling current flowing through the first MOS transistor to obtain first sampling current; the second sampling circuit is used for sampling current flowing through the fourth MOS transistor to obtain second sampling current; the current processing circuit is used for generating third sampling current accordingto the first sampling current and the second sampling current; and the average value of the third sampling current in one circuit working period represents the output current of the boost-buck circuit. Compared with the prior art, the current sampling circuit has the advantages that the current sampling function inside a chip is realized; the power loss and chip pin quantity are reduced; and the system cost is lowered.

The invention relates to a sampling device and a sampling method for pumping a gas sample in a self-negative-pressure pipeline, which can be widely applied to a sampling step of checking front coal gas of draught fans of steel, coking and chemical industries. According to the sampling device, a coal gas pipeline is externally connected with a first gas conveying pipe and one end of the first gas conveying pipe is inserted into a liquid level in an absorption liquid bottle; a water injection pipe and a gas inlet pipe are arranged at the top of a sealed water tank; one end of a second gas conveying pipe is guided out from the top of the absorption liquid bottle and is connected onto the gas inlet pipe; a water discharging pipe is arranged at the bottom of the sealed water tank; the first gas conveying pipe, the second gas conveying pipe, the water injection pipe and a water discharging pipe are provided with valves respectively; a measuring cylinder with scales is arranged below the water discharging pipe. The invention introduces the sampling method based on the device. The invention explores a new way for a negative-pressure sampling manner of the coal gas so as to effectively avoid inaccurate measurement of a sampling volume and avoid mixing air. The accuracy of the negative-pressure sampling of the coal gas is guaranteed.

The invention discloses a voltage and phase sequence protection circuit, which comprises a voltage sampling part and a logic control output part, wherein the voltage sampling part consists of two groups of circuits of which each comprises a voltage transformer and a sampling conversion circuit unit; and the logic control output part comprises a microchip module, a resetting circuit module, an oscillating circuit module and an output circuit module. The circuit further comprises a power circuit module and a communication circuit module. The voltage and phase sequence protection circuit provided by the invention simultaneously realizes voltage and phase detection, improves circuit sensitivity, simplifies a circuit structure, can work independently of an independent external power supply dueto structural improvements in the power circuit module, and also can be conveniently connected with other control systems for intelligent control by the communication circuit module, so functions andapplication modes of the circuit are expanded.

The invention discloses a device and method for measuring the coking tendency of solid-containing heavy raw materials. A heated heater, a heating device that is in suspension and provides heat to the solid-containing heavy raw material is provided inside the sample cell, and a sleeve for attaching coke particles is provided outside the heating device, The top of the casing is connected to a weighing device, and the weighing device measures the quality of the electric heating rod casing and the change in the mass of the electric heating rod casing caused by the heating and coking of the reaction raw materials in real time. The weighing device is connected with the data acquisition module; the data acquisition module is connected with the data processing module, and the data processing module processes the signal of the balance to obtain the percentage of the amount of coke.

The double port network parameter measuring method includes: correcting the sampling channels and obtaining the sampling channel difference parameter; measuring the input voltage on the sampling resistor and that of the double port network with the corrected the sampling channels; and obtaining the true voltage values with the channel difference parameter and the measured voltage values and calculating the impedance parameters of the double port network with relevant formula. The present invention has raised measurement accuracy.