JPH0836064A - Optical sensor controlling method - Google Patents

Abstract

PURPOSE:To detect only a stained sensor and prevent an impediment of the sensor due to the stains by cleaning the sensor. CONSTITUTION:Based on the fact that the sensor output becomes larger when a sensor is stained more, it is judged that there is no margin for stains in the case where the sensor output value under a condition of no obstacle is compared with a previously stored stain margin check value and the output value is found higher than the stain margin check value, and the result is displayed on a displaying apparatus. Meanwhile, in the case where the output value is found smaller than the margin check value, it is judged that there is a margin. In this way, only a detected sensor is cleaned. Before the comparison of the output value with the stain margin check value, the current of an electroluminescent element is made to be a weak current in order to make the alteration of the sensor output value large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method of an optical sensor for detecting paper sheets, and more particularly to a stain margin check control method for detecting an optical sensor which may be erroneously detected due to dust adhesion.

[0002]

2. Description of the Related Art Conventionally, an optical sensor for detecting the presence or absence of a ticket, an admission ticket, a bill, etc. has been used in a ticket vending machine, a cash transaction device, a paper sheet detection device, etc., and read by the optical sensor. The voltage and the reference voltage are compared, and it is determined that the paper or the like is present when the reading voltage is higher than the reference voltage, and it is determined that the paper is not present when the reading voltage is lower than the reference voltage. However, since the surface of the optical sensor is contaminated by particles, fibers, contaminants, etc., which are carried by the air when passing through the paper, the function is deteriorated, and as a result,
Reduce the illumination level of the sensor. Therefore, ideally, it is necessary to perform maintenance such as cleaning from time to time to maintain the function, but it is expensive because it requires manpower, and it is necessary to stop the function during that time. As a measure against this,
For example, in the method disclosed in Japanese Patent Laid-Open No. 62-65188, the sensitivity of the sensor is switched at a constant level, and the sensor sensitivity is switched every time a fixed period of time elapses. In addition, for example, Japanese Patent Laid-Open No. 1-22338
In the paper sheet detection device described in Japanese Patent Publication No. 6, when it is determined that there is a paper sheet even though there is no paper sheet,
Since the optical sensor (light emitting element and light receiving element) is contaminated with dust, it is judged that there is no margin in the light emission amount, the light emission level is increased by 2 ranks by the automatic adjustment circuit, and the value is stored,
Perform processing. In this way, the amount of light emission is always provided with a surplus power for detection. In addition, for example, Japanese Patent Laid-Open No. 63-
In the sensor detection device described in Japanese Patent No. 47691, the output of the optical sensor is digitized and read by the microprocessor, the determination level previously stored in the storage unit is compared with the detected data, and the new determination level is determined. It describes a method of creating and storing this new determination level in the storage unit as the next determination level.

[0003]

As described above, in the prior art, the method of changing the light emission amount of the optical sensor or the old determination level of each optical sensor is stored in advance.
A method of creating and storing a new judgment level by comparing with the output of the optical sensor, or a method of adjusting the gain of the amplifier on the light receiving side so that the output of the optical sensor is constant, or both the amount of emitted light and the slice level. A method of operating by changing the amount of emitted light by switching the switch and checking the dirt has been performed. However,
In these methods, if dust adheres to only a small number of the sensors, it is unclear which sensor should be cleaned, and as a result, all the sensors should be cleaned. It is necessary to perform unnecessary work for the sensor of, and this is troublesome. In addition, it is necessary to perform control such as changing the determination level or switching the amount of emitted light, even if only a specific sensor is cleaned to obtain a sensor similar to a new one. An object of the present invention is to solve these conventional problems, detect only a sensor with dirt attached by a margin check, and clean the sensor to prevent a sensor failure due to dirt. It is to provide a control method.

[0004]

In order to solve the above-mentioned object, an optical sensor control method of the present invention comprises: (i) controlling a light emitting operation of a light emitting element by a light emitting current control element, and controlling the light emitting element. In order to detect the output value of the corresponding light receiving element and determine the presence or absence of a shield between the light emitting element and the light receiving element,
The slice level is set in advance, and in the optical sensor that determines the presence or absence of a shield by comparing the output value of the light receiving element with the slice level, the dirt margin check value of each optical sensor is stored in the storage unit. The output value of the light receiving element is compared with the stain margin check value to determine the margin for stain. Further, (ii) the current flowing through the light emitting element is reduced, and the output value of the light receiving element at the time of the reduction is compared with the stain margin check value.

[0005]

In the present invention, a plurality of light emitting elements are sequentially switched by the light emission current switching process to emit light, and a plurality of sensor controls are performed by reading the output value of the sensor emitted by the light receiving output switching section. And
The "1" and "0" judgments are performed by the CPU by referring to the slice level stored in the ROM. When it is determined to be “0”, that is, when it is determined that there is no banknote, the current flowing through the light emitting element is set to a weak current state, and the output value is compared with the margin check value stored in advance. If it is larger than the check value, it is judged that there is no margin, and if it is smaller, it is judged that there is a margin. In this way, the plurality of sensors are sequentially checked. In this way, according to the present invention, it is possible to prevent erroneous detection due to adhesion of dirt, and to detect a sensor with dirt by margin check and clean it to prevent sensor failure due to dirt. You can

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of an optical sensor control unit to which the present invention is applied. In FIG. 1, the sensors S1 to Sn are composed of light emitting diodes LED1 to LEDn and phototransistors PT1 to PTn, respectively. Light emitting diodes LED1 to LE of the sensors S1 to Sn
Dn is controlled by the LED1ON to LEDnON signals for switching the emission current, which the CPU 1 outputs via the output port 7. By turning on the LED drive transistor TR1 by the LED1 ON signal, the light emission current IF1
And the light emitting diode LED1 emits light. Also, C
The amount of light emission current can be switched by the VLED switching signal output from PU1 via the output port 7. V
When the LED transistor Tr0 is ON, a stronger current than + 15V flows, and when the transistor Tr0 is OFF +
A weak current flows from 5V. The collectors of the phototransistors PT1 to PTn, which are the light receiving elements of the sensors S1 to Sn, are connected to the analog multiplexer 6, respectively, and the sensors selected by the sensor output select signal output from the CPU 1 via the output port 7 are selected. Output is A
It is converted into a digital value by the / D converter 5 and input to the CPU 1. The light emitting diodes LED1 to LEDn are caused to emit light in the order of the sensors S1 to Sn, and the sensors that have emitted light are selected by the analog multiplexer 6, whereby the output of each sensor is sequentially read.

FIG. 6 and FIG. 7 are flowcharts of the general processing for determining the presence or absence of banknotes in FIG. 1 and S in FIG.
It is a figure which shows the content of the slice level storage area stored in RAM. In FIG. 1, first, the VLED transistor Tr0 is turned on and kept in a strong current state (step 201). Next, the sensor S1 is turned on (step 2
02), the output value of the sensor S1 is read (step 20).
3). The read output value is compared with the S1 slice level stored in the slice level storage area of the SRAM 3 (step 204). If the output value is larger than the slice level, it is determined that there is a bill (steps 205, 20).
6) If the output value is smaller than the slice level, it is determined that there is no bill (step 207). When the judgment is completed,
The sensor S1 is turned off (step 208). Similarly, the presence / absence of banknotes is determined in the order of the sensors S2, S3, ... (Steps 209 ... 210). Note that FIG.
Is a bill presence / absence determination processing flow during normal operation,
Presence / absence determination processing is performed on a large number of sensors in a time division manner. As shown in FIG. 7, in the slice level storage area of the SRAM 3, the output value of the light receiving element is measured in the state where there is no shield between the light emitting element and the light receiving element, and the slice level updated accordingly. Store. The S1 slice level means the latest slice level of the sensor S1. Slice levels from S1 to Sn are stored.

FIG. 4 is a diagram showing the contents of the slice level update table, and FIG. 5 is a diagram showing the sensor output waveform. Light emitting diode LED1 and phototransistor PT
When there is no shield between 1 and when there is no stain, an output of about 0 V is obtained (see FIG. 5 (b)). If the shield is a substance that completely blocks light, the sensor output changes to about 5 V in the shielded state. However, since the banknotes transmit light to some extent, the amount of change in the sensor output is small in the shielded state, and it is necessary to set the slice level to a low value in order to detect the presence or absence of the banknotes. However, if dirt is attached to the sensor, the sensor output becomes high even when there is no shield, and if the slice level is exceeded, it is determined that there is a bill even though there is no bill. Therefore, the slice level is updated by the sensor output value in the state where there is no shield, thereby preventing erroneous detection due to adhesion of dirt.

First, in order to detect the presence or absence of banknotes, FIG.
The VLED transistor Tr0 in the above is turned on and kept in a strong current state. Next, the sensor S1 is turned on and the output value of the sensor S1 is read. Read output value and SRAM
The S1 slice level stored in No. 3 is compared, and when the output value is larger than the slice level, it is determined that there is a bill, and when the output value is smaller than the slice level, it is determined that there is no bill. When it is determined that there is no bill, the slice level update table (see FIG. 4) of the ROM 2 is referred to, the slice level of the corresponding output value is obtained, and the slice level value stored in the SRAM 3 is rewritten. For example, as shown in FIG. 5, when there is no banknote and no stain, the sensor output value is a level 1 value close to 0 V, and slice level 1 is set (see FIG. 5B). When dirt adheres, the sensor output value rises and rises to level 2 close to slice level 1 (see FIG. 5 (d)). In this state, since the sensor output value is slightly lower than the slice level 1, it can be determined that there is no banknote, but it is erroneously detected that there is a banknote with a little dirt attached. Therefore, the slice level is updated to the slice level 2 corresponding to the output value level 2 by the slice level update process to prevent erroneous detection due to contamination.

When it is determined that there is a bill, the slice level is not updated and the sensor S1 is turned off. Similarly, the slice level is updated up to Sn in the order of S2 and S3. Since the SRAM 3 is backed up by the battery 4, the slice level is stored even when the power is turned off, and the next time the power is turned on, the presence / absence of a bill is determined using the slice level updated last time. You can In this way, the slice level update process is performed without the banknotes, but in reality, the update process is performed using the time between operations, so it is natural that a There is a part of the bill in.
Therefore, it should be noted that the sensor is not necessarily a bad sensor when the processing is performed in such a place. For such a sensor, the slice level is updated by checking at another occasion.

Next, the method for checking the margin against dirt on the sensor will be described with reference to FIGS. FIG. 2 is a flowchart of the dirt margin check operation according to the embodiment of the present invention, and FIG. 3 is a diagram showing the contents of the dirt margin check value table. The dirt margin check value stored in the table of FIG. 3 is set for each sensor S1 to Sn and is a fixed value. In each sensor, the gap between the light emitting diode and the phototransistor differs depending on the installation location, and a stain margin check value suitable for each center is set for each center. Since the sensor output increases when dirt adheres to the sensor, the degree of dirt of the sensor can be determined by the sensor output value in the state where there is no shield. First, in order to detect the presence / absence of a bill, the VLED transistor Tr0 is turned on and kept in a strong current state (step 101). Next, the sensor S1 is turned on (step 102), and the output value of the sensor S1 is read (step 103). The read output value is compared with the S1 slice level stored in the SRAM 3 (step 104). If the output value is larger than the slice level, it is determined that there is a bill (step 1).
05), if the output value is smaller than the slice level, it is determined that there is no bill (step 105).

When it is determined that there is no banknote, the VLED transistor Tr0 is turned off so that the change in the sensor output value due to dirt becomes large (step 106), the weak current state is set, and the output value of the sensor S1 is read (step 10).
7). The value is compared with the S1 dirt margin check value of the ROM 2 (see FIG. 3) (step 108), and when the output value of the sensor S1 is larger than the S1 dirt margin check value, it is determined that there is no margin for dirt (step 11).
0). When the output value of the sensor S1 is smaller than the S1 dirt margin check value, it is determined that there is a margin for dirt (step 111). On the other hand, when there is a bill (step 105), the margin check is not performed and the sensor S1 is turned off (step 112). Similarly, the margin check is performed until Sn in the order of S2 and S3 (steps 113 and 114), and the number of the sensor determined to have no margin for dirt is displayed on the display 9 via the display controller 8. (Step 115).

As described above, the present embodiment is characterized in that the current of the light emitting element is switched to the weak current so that the change in the sensor output value due to the dirt becomes large after it is determined that there is no bill. By reading the output value of the sensor S1 in the weak current state, the output value is compared with the stored margin check value, and when the output value is large, it is determined that there is no dirt margin, and an alarm is sent or displayed. Display on the container. Note that when there is a bill, the sensor is turned off without performing any processing, but during operation, there is always a portion where there is a bill, such as a dispensing box. You can check at the opportunity. Further, in the case of the dirt margin check, the sensor number without the dirt margin is displayed on the display device in step 115, so that the "display of the sensor number with banknote" is also performed so that the maintenance staff or the staff can judge. Good.

[0014]

As described above, according to the present invention,
Since the sensor attached with dirt can be detected by the margin check, the sensor failure due to the dirt can be prevented by cleaning only the sensor.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical sensor control unit to which the present invention is applied.

FIG. 2 is a flowchart of a stain marine check process according to an embodiment of the present invention.

FIG. 3 is a diagram showing the contents of a dirty margin check value table stored in the ROM of FIG.

4 is a diagram showing the contents of a slice level update table stored in the ROM of FIG.

FIG. 5 is a diagram showing a sensor output waveform in the present invention.

FIG. 6 is a normal bill presence / absence determination flowchart.

7 is a diagram showing the contents of a slice level storage area stored in the SRAM of FIG.

[Explanation of symbols]

1 CPU, 2 ROM, 3 SRAM, 4 batteries, 5
A / D converter, 6 analog multiplexer, 7
Output port, 8 display control section, 9 indicator, 10 banknote, S1 to Sn sensor, LED1 to LEDn light emitting diode, PT1 to PTn phototransistor, TR
1-TRn LED drive transistor, TR0 VLE
D transistor.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G07B 5/00 F G07D 7/00 E

Claims (2)

[Claims] 1. The light emitting operation of a light emitting element is controlled by a light emitting current control element, an output value of a light receiving element corresponding to the controlled light emitting element is detected, and presence or absence of a shield between the light emitting element and the light receiving element is detected. In order to make a determination, a slice level is set in advance, and in an optical sensor that determines the presence or absence of a shield by comparing the output value of the light receiving element with the slice level, the storage unit stores the stain margin check value of each optical sensor. The optical sensor control method, wherein the output value of the light receiving element is compared with the dirt margin check value to determine the margin for dirt. 2. The optical sensor control method according to claim 1, wherein the current flowing through the light emitting element is reduced, and the output value of the light receiving element at the time of the reduction is compared with the stain margin check value. Optical sensor control method.