A two-wire position transmitter circuit

Abstract

The invention provides a two-wire position transmitter circuit. The two-wire position transmitter circuit comprises a position potentiometer, a microprocessor, a voltage regulator and a current output circuit, wherein the position potentiometer is connected with an A / D (analog / digital) channel pin of the microprocessor through a second line bank; the input end of the voltage regulator is connected with an external power supply through a first line bank; the output end of the voltage regulator supplies power to the microprocessor; one end of the current output circuit is connected with a PWM (Pulse Width Modulation) output pin of the microprocessor; and the other end of the current output circuit is connected with the first line bank and outputs current outwards. Analog / digital conversion is performed by a PIC (Peripheral Interface Controller) microprocessor and a peripheral voltage reference circuit to achieve position signal acquisition, computational processing is performed by a program, and a 4-20mA current signal is output by the PWM circuit and the peripheral current output circuit; and due to the adoption of a digital circuit and program processing, the stability of the two-wire position transmitter circuit is high.

Description

technical field [0001] The invention relates to a position transmitter circuit, in particular to a two-wire position transmitter circuit that receives power from an external circuit through two transmission lines and transmits a current signal to the outside. Background technique [0002] Based on the principle of differential capacitance, the position transmitter converts the rotational angle or linear displacement into a standard current signal to detect various valve opening and displacement variables. [0003] In the industry, it is generally necessary to measure various non-electrical physical quantities, such as temperature, pressure, speed, angle, etc. In addition, electrical physical quantities (referred to as electricity), such as current, voltage, power, frequency, etc., need to be converted into standard analog electrical signals for transmission. to a control room or display device several hundred meters away. This device that converts physical quantities into e...

AI Technical Summary

Problems solved by technology

[0007] Position transmitters in the existing technology often use analog circuits, which have poor stability

The original product uses two potentiometers to adjust the positions of both ends. It needs repeated adjustments to adjust it well, and there are still changes and drifts during use.

At the same time, in order to stabilize the product performance, the original product needs to be perfused and cured with resin, which increases the cost and man-hours, and cannot be repaired.

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