JPS6282373A - Automatic controller for sensitivity of magnetic sensor - Google Patents

Abstract

PURPOSE:To remove intricacy in adjustment for every device and to eliminate its error, and to adjust the sensitivity of a sensor accurately and automatically by providing a magnetic field generating means and a switch part, a gain varying means and a control means, etc. CONSTITUTION:A control part 17 outputs a control signal to the switch part 16 of a magnetic field generation part 13 in a stationary state wherein a body to be detected is not inserted, thereby turning on the switch part 16. Consequently, a conductor 15 produces a magnetic field to the magnetic sensor 10 and its magnetic pattern is outputted to an amplifier 11 and inputted to the control part 17. It is compared in the control part 17 with a reference voltage signal which is inputted previously and a control signal regarding the difference is outputted to a gain controller 12 to control the gain of the amplifier 11, adjusting and controlling the gain to a constant value. In a dynamic state in which the body to be detected is inserted, on the other hand, a detection sensor detects the object body and when its detection signal is inputted to the control part 17, the control part 17 turns off the switch 16. Consequently, the conductor 14 stops generating the magnetic field to the sensor 10, which outputs the magnetic pattern of the object to the amplifier 11.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic sensor sensitivity automatic control device, and in particular,
When there is no object to be detected in the device, a constant magnetic field is generated for the magnetic sensor, and the gain of the amplifier connected to the magnetic sensor is controlled based on the reference voltage signal to increase the sensitivity of the magnetic sensor. The present invention relates to a magnetic sensor sensitivity automatic control device that automatically performs adjustment control.

[Conventional technology]

Conventionally, the method shown in FIG. 4 has been used as a method for adjusting the sensitivity of a magnetic sensor.

FIG. 4(a) shows a magnetic reference paper 4 on which an ink 3 containing a magnetic substance is printed on the surface of the paper 1 that contacts the magnetic sensor 2.

FIG. 4 (0) shows a magnetic sensor sensitivity adjustment device. The magnetic sensor 2 includes an amplifier 5 for amplifying the signal from the magnetic sensor 2, and the output of the amplifier 5 is set to a constant base value. A variable resistor 6 is provided for this purpose.

In the above configuration, when the magnetic reference paper 4 is passed over the magnetic sensor 2, the magnetic sensor 2 is activated based on the magnetic material pattern of the magnetic reference paper 4, and outputs a detection signal based on the operation to the amplifier 5. 5 amplifies and outputs the detection signal. The output signal is compared with the base value set in advance for each magnetic reference paper 4, and if there is a difference between the two, the output gain of the amplifier 5 is changed using the variable resistor 6. and adjust it to match the reference value.

[Problem that the invention seeks to solve]

However, in the conventional magnetic sensor sensitivity adjustment method, it is necessary to actually pass the magnetic sensor using a magnetic reference paper 4 printed with ink containing a magnetic substance, so the sensitivity of the magnetic sensor can be adjusted for each device. In addition, the magnetic material printed on the magnetic reference paper may wear out due to contact operations with the magnetic sensor, or the magnetic reference paper may separate from the magnetic sensor during sensor sensitivity adjustment, causing the actual In addition, the output may be reduced, and variations in magnetic ink density may occur.
Due to variations in printing accuracy, etc., there is a risk that adjustment errors will become large.

[Means and effects for solving the problems] The present invention has the following features:
This was done in view of the above, and in order to eliminate the complexity of having to make adjustments for each device, eliminate device errors, and automatically adjust the magnetic sensor sensitivity accurately, it is possible to Automatically adjusts and controls the sensitivity of the magnetic sensor by arbitrarily generating a constant magnetic field for the magnetic sensor in the absence of an object, and controlling the gain of the amplifier connected to the magnetic sensor based on the reference voltage signal. The present invention provides a magnetic sensor sensitivity automatic control device.

〔Example〕

Hereinafter, one embodiment of the magnetic sensor sensitivity automatic control device according to the present invention will be described in detail.

1 and 2 are explanatory diagrams showing the structure of an automatic magnetic sensor sensitivity control device according to the present invention.

a magnetic sensor 10 that detects a magnetic pattern of an object to be detected (not shown), and a magnetic sensor 1 connected to the magnetic sensor 10;
7 amplifier 11 for amplifying the detection signal detected by 0;
It includes a gain controller 12 that controls the gain of the amplifier 11 based on a control signal from a control section, which will be described later, and a magnetic field generation section 13 that provides a specific magnetic pattern to the magnetic sensor 10. The magnetic field generator 13 includes a conductor 14 (conductor 14 ) that generates a magnetic field for the magnetic sensor 10 .
2 (as shown in () and (11), it is located at a predetermined distance (A thickness of the object to be detected) from the magnetic sensor 10 and is located at the top), and the power is applied to the conductor yA14. It is composed of an AC power source 15 that supplies the magnetic field, and a switch section 16 that turns ON and OFF the generation of a magnetic field. The control unit 17 controls the switch unit 16 and the gain controller 12.
(for example, a microcomputer).

The control unit 17 includes an input interface 19 that inputs a sensor signal from the object detection sensor 18 shown in FIG. 2, a reference voltage signal, and an output signal from the amplifier 11, and a program necessary for processing the input signals. ROM to store
20, and a CPU that performs predetermined calculations based on the program.
21 and RAM that temporarily stores calculation results, data, etc.
22, and an output interface 23 that outputs a control signal to the switch section 16 of the magnetic field generation section 13 and the gain controller 12 based on the calculation result.

The operation will be explained in the above configuration.

(1) When there is no detected object In a static state where no detected object is inserted, the control section 17 outputs a control signal to the switch section 16 of the magnetic field generation section 13 to turn the switch section 16 on. Keep it in ON state.

As a result, the conducting wire 14 generates a magnetic field for the magnetic sensor 10, and the magnetic sensor 10 is sensitive to the magnetic field and outputs the magnetic pattern to the amplifier 11, which amplifies and outputs the magnetic pattern signal. . The amplified signal is input to the control unit 17 and compared with the base 11ζ voltage signal input in advance within the control unit 17, and a control signal regarding the difference is output to the gain controller 12. Control gain. The gain of the amplifier 11 is always adjusted and controlled using this route.

(2) When a detected object is inserted When the detected object is inserted and the detected object is in the moving state, the detected object detection sensor 18 detects the detected object and inputs a detection signal to the control unit 17. turns the switch unit 16 into the OFF state. As a result, the conducting wire 14 stops applying a magnetic field to the magnetic sensor lO. Instead, the magnetic sensor 10 is sensitive to the magnetic pattern of the detected object being conveyed, and outputs the magnetic pattern to the amplifier 11, which amplifies and outputs the magnetic pattern signal. FIG. 3 shows the mutual relationship between the ON and OFF operations of the detection object sensor 18 and the switch unit 16.

〔Effect of the invention〕

As explained above, according to the magnetic sensor sensitivity automatic control device according to the present invention, a constant magnetic field is arbitrarily generated for the magnetic sensor in a state where there is no object to be detected in the device, and a magnetic field is generated based on the reference voltage signal. The sensitivity of the magnetic sensor is automatically adjusted and controlled by controlling the gain of the amplifier connected to the sensor, which eliminates the complexity of having to make adjustments for each device, eliminates adjustment errors, and improves the sensitivity of the magnetic sensor. Accurate adjustments can be made automatically.

[Brief explanation of drawings]

Fig. 1 is a structural explanatory diagram of the magnetic sensor sensitivity automatic control device according to the present invention, Fig. 2 C) and (II) are explanatory diagrams showing the arrangement of each part in the present invention, and Fig. 3 is an explanatory diagram showing the detection object sensor and switch. FIG. 4 ((), (+1) is an explanatory diagram showing a conventional method of adjusting the sensitivity of a magnetic sensor. Explanation of symbols 10・-- ---Magnetic sensor 11-・-Amplifier 1
2.--.--Gain controller 13--1 Magnetic field generation section 16-.--.Switch section 17-.
-Control unit 18-----Detected object detection sensor Patent applicant Toyo Tsushinki Co., Ltd. Agent Patent attorney Shin Matsubara 2 Same member Kiyo Junma Muraki
Same as above Jun Shima - Same as above
Hiroshi Sakai Figure 2 Figure 3 S”” ON OFF Figure 4

Claims (1)

[Scope of Claims] A magnetic sensor sensitivity automatic control device that automatically adjusts and controls the sensitivity of a magnetic sensor that reads a magnetic pattern of an object, comprising: a magnetic field generating means that generates a predetermined magnetic field for the magnetic sensor; , a switch section for turning on and off the magnetic field generating means, a gain changing means for changing the gain of an amplifier that amplifies the output from the magnetic sensor, and a control means for operating the switch section and the gain changing means. When there is no object to be detected in the apparatus, the control device turns on the switch section and changes the gain of the amplifier via the gain changing means based on a reference signal input to the control section. and when there is an object to be detected in the device, the control section turns off the switch section, and the magnetic sensor detects the magnetic pattern of the object. Control device.