RU2378658C1 - Microcontroller for measuring shaft rotation frequency - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: invention relates to measurement technology particularly to the devices for measuring shaft rotation frequency using a capacitance sensor and can be used in automatic process control systems to measure nonelectrical quantities. The microcontroller for measuring shaft rotation frequency contains a microcontroller, an indicator, a capacitance sensor and two resistors. The indicator is connected to one of the microcontroller ports. The first plates of the sensor and the capacitor are connected to the common wire, the second plates of the sensor and the capacitor are connected to the first and second ports of the analog comparator of the microcontroller respectively, as well as to the first terminals of the resistors whose second terminals are connected to the microcontroller terminals.

EFFECT: simplified diagram and extended capabilities of the device namely it enables to measure either the shaft rotation frequency or the sensor capacity.

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Description

FIELD OF THE INVENTION

The invention relates to measuring equipment, in particular to devices for measuring the shaft speed by capacitive sensors, and can be used in automated process control systems for measuring non-electrical quantities.

State of the art

A device for measuring electric capacitance and / or active resistance, comprising two one-vibrators, included in a ring circuit, a pulse generator and an indicator, capacitors of the measured capacitance and an exemplary capacitor, respectively, are included in the timing circuits of the first and second one-vibrators, the generator output is connected to the start inputs of both single-vibrators, an indication unit is connected between the second outputs of the single vibrators, the indication unit indicates an excess of one capacity in relation to another (see US Pat. RF No. 2099724, class G01R 27/26).

A disadvantage of the known device is limited functionality. A device for measuring electric capacitance is known, containing two single-vibrators connected according to a circular oscillator circuit, capacitors of the measured capacitance and an exemplary capacitor, respectively, two integrating links connected to the outputs of the corresponding single-vibrators, an indicator connected between the outputs of the integrating links are included in the timing circuit of the first and second single vibrators. A constant voltage is formed at the output of the device, which depends on the change in the measured capacitance and is reflected by an indicator (see Pat. RF No. 2156472, class G01 27/26).

A disadvantage of the known solution is limited functionality. The closest in technical essence to the claimed technical solution and adopted by the authors for the prototype is a device for measuring non-electric quantities by capacitor sensors, containing a microcontroller (MK), an indicator, first and second generators, during the timing chains of which are connected respectively a capacitive sensor and a reference capacitor, generator outputs connected to the inputs of the MK, the indicator is connected to one of the ports of the MK (see US Pat. RF No. 2214610, class G01 27/26).

A disadvantage of the known solution is a relatively complex scheme and limited functionality.

Disclosure of invention

The technical result that can be achieved using the present invention is to simplify the circuit and expand the functionality of the device, namely, the device allows you to measure either the shaft speed or the sensor capacitance.

The technical result is achieved by the fact that in the microcontroller device for measuring the shaft speed containing MK, an indicator, a capacitive sensor and a reference capacitor, which are connected to the common wire by the first plates, the indicator is connected to one of the MK ports, the first and second resistors are introduced, and the second the plates of the capacitive sensor and the reference capacitor are connected, respectively, to the first and second inputs of the analog comparator MK and to the first terminals of the first and second resistors, the second terminals of which are are connected to MK exits.

Brief Description of the Drawings

The drawing shows a structural diagram of a microcontroller device for measuring the frequency of rotation of the shaft.

The implementation of the invention

The microcontroller device for measuring the shaft speed contains (see Fig.) MK 1, indicator 2, capacitive sensor 3 and a reference capacitor 4, resistors 5 and 6. Indicator 2, the first plates of sensor 3 and capacitor 4 are connected to one of the ports of MK 1 connected to a common wire, the second plates of the sensor 3 and capacitor 4 are connected respectively to the first and second inputs of the analog comparator built into MK 1 (not shown) and to the first terminals of the resistors, respectively 5 and 6, the second terminals of which are connected to the outputs of MK 1. On the shaft (not shown) the engine, the speed of which you want to measure, pressed the gear, which is the first cover of the sensor 3. The gear teeth move relative to the motionless fixed second cover of the sensor 3. When the gear tooth approaches the second cover of the sensor 3, its capacity increases.

Microcontroller device for measuring the speed of the shaft operates as follows.

At the beginning of each measurement cycle, MK 1 clears the built-in pulse counter, discharges the sensor 3 and capacitor 4 by simultaneously supplying low voltage levels through resistors 5 and 6 and starts the built-in timer to form a time interval. Then MK 1 delivers a high voltage level through the resistor 5 to the sensor 3 and after a certain time delivers a high voltage level through the resistor 6 to the capacitor 4. The voltage rise rates on the sensor 3 and capacitor 4 depend on their capacitance.

At the beginning of the charge of the sensor 3, the voltage on it is less than the voltage on the capacitor 4. A logical 0 is generated at the output of the analog comparator MK 1. As soon as the voltage on the capacitor 4 exceeds the voltage on the sensor 3, a logical 1 is generated at the output of the analog comparator MK 1. pulses MK 1 will increase by one. MK 1 proceeds to a new measurement cycle. If the capacity of the sensor 3 is less than the capacity of the capacitor 4, (the gear tooth did not fit the second plate of the sensor 3), then the logical 1 will not appear at the output of the analog comparator MK 1. Thus, the contents of the pulse counter MK 1 will increase by one each time the gear tooth passes near the second cover of the sensor 3. As soon as the timer MK 1 counts the specified time interval, the contents of the pulse counter are read, processed by the processor MK 1 and displayed on indicator 2.

Advantages of the invention: the scheme is simplified and the functionality of the device is expanded, namely, the device allows you to measure either the shaft speed or the sensor capacity.

Claims (1)

A microcontroller device for measuring the shaft speed containing a microcontroller, an indicator, a capacitive sensor and a reference capacitor, which are connected to the common wire by the first plates, the indicator is connected to one of the ports of the microcontroller, characterized in that the first and second resistors are inserted into it, the second plates the capacitive sensor and the reference capacitor are connected respectively to the first and second inputs of the analog comparator of the microcontroller and to the first terminals of the first and second resistors , the second conclusions of which are connected to the outputs of the microcontroller.