Resistance detection circuit of potentiometer for anesthesia apparatus motor valve positioning

Abstract

The invention provides a resistance detection circuit of a potentiometer for anesthesia apparatus motor valve positioning. The resistance detection circuit comprises an amplified-signal conditioning circuit and a circuit loop drive; the amplified-signal conditioning circuit is used for converting high-impedance voltage signals corresponding to a center tap of the potentiometer into low-impedance voltage signals prior to outputting the low-impedance voltage signals into the circuit loop drive; the circuit loop drive provides reference voltage to the potentiometer via an external power source, converting received voltage signals into current signals, taking the current signals as transmission signals subjected to resistance detection of the potentiometer, and outputting the current signals. The voltage signals output by the potentiometer through the electric loop drive of the circuit are converted into the current signals which are transmitted as the transmission signals subjected to resistance detection of the potentiometer, the problem that the voltage signals of the potentiometer, directly transmitted are prone to interference can be solved, and heating of the potentiometer powered by directly adopting the constant flow source can be avoided.

Description

Technical field [0001] The invention relates to the technical field of motor valve positioning of an anesthesia machine, in particular to a resistance value detection circuit of a potentiometer used for positioning the motor valve of an anesthesia machine. Background technique [0002] In an anesthesia machine controlled by a stepping motor valve, the stepping motor controls the opening of the needle valve, thereby realizing the control of the tidal volume. In this control process, it is necessary to know the position of the stepping motor, and then obtain the opening of the needle valve, so as not to cause the needle valve to jam. Position indication generally uses potentiometers, stepping motors, needle valves, and potentiometers are coaxial. When the stepping motor rotates, it drives the needle valve and potentiometer. At this time, the stepping motor rotates a certain angle, and the resistance value of the potentiometer also changes accordingly. In this way, the change in th...

AI Technical Summary

Problems solved by technology

However, the variable voltage signal generated by the middle tap of the potentiometer is a high-impedance signal, and the anti-interference ability is very poor. Especially when the stepper motor is rotating, the pulse signal driving the stepper motor will have a strong impact on the surrounding environment. Interference, so the accuracy of the method of using the reference voltage source to detect the voltage change of the potentiometer is relatively low

If you use a reference current source to drive the potentiometer, you need to use a potentiometer with a small resistance, so that the current passing through the potentiometer will be relatively large, and the current signal has strong anti-interference ability, but it will greatly affect the performance of the potentiometer. Requirements, the resistance value of the potentiometer should not be too large, otherwise, the heat will be more serious, and if it is driven by a small current source, it will not be able to achieve the effect of a constant current source

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