JPH0248947B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reading barcode data, and more particularly, the present invention relates to a method for reading barcode data, and more specifically, a method for displaying product-related data by the number of barcodes, and arranging the barcodes at intervals corresponding to the number of barcodes. , optically reads the number of barcodes and their spacing, determines whether the barcode has been read accurately based on the correspondence between the number and spacing, and prevents misreading of barcode data to improve product quality. The present invention relates to a barcode data reading method for determining type, shape, etc.

In recent years, many products have appeared in which data such as product price, product number, date of manufacture, etc. are marked on the product using barcodes. In this case, the barcode is usually a combination of thick black lines and thin black lines depending on the data, arranged and labeled at predetermined intervals. Therefore, barcode data is read by detecting the difference in reflectance of each barcode using an optical sensor.

On the other hand, such a method of identifying products using barcodes is extremely useful, for example, when assembling various parts in an engine. In other words, the main components of an engine include a cylinder block in which the piston is housed, a crankshaft built into the journal bearing of the cylinder block, and a connecting rod that connects the piston and crankshaft. The bearings are fitted during assembly. In this case, it is inevitable that the cylinder block, crankshaft, and connecting rod will have an error of about several μm in their machining accuracy during machining. Therefore, in order to ensure smooth engine operation, it is necessary to select and combine bearings of optimal size for each member.

However, if a worker were to manually assemble these members one by one, it would take a lot of time, and moreover, there is a possibility that mistakes may occur in the assembly.

Therefore, if a bar code is marked on each component according to its size, and the bar code is read optically to select the most suitable bearing, it is possible to avoid mistakes in product combination by workers. This makes it possible to accurately and efficiently assemble the engine without causing any problems.

However, when a bar code is marked on such a member by printing or the like, the marked portion may sometimes become unclear due to oil stains, etc., and there is a risk that accurate reading of the bar code may become impossible.

Therefore, a method has been considered in which a bar code is engraved on a member constituting the product and the change in the amount of reflected light due to the engraved code is optically read. However, depending on the accuracy of the engraving, the barcode may become blurred or crushed, and on the other hand, it is not easy to distinguish whether the barcode is stamped as a thick line or as a thin line, resulting in reading errors. I was afraid. Therefore, when engraving a barcode,
Misreading due to oil stains, etc. can be prevented, but
Since the reading accuracy largely depends on the accuracy with which the barcode is engraved, it has been almost impossible to encode data based on differences in the thickness of the inscriptions.

The present invention has been made in order to overcome the above-mentioned disadvantages, and the present invention displays data regarding a product by the number of barcodes and the spacing between the barcodes corresponding to the number, and from the correspondence between the number and the spacing. It is an object of the present invention to provide a barcode data reading method that prevents misreading of barcode data by determining whether or not the barcode has been accurately read, and that enables accurate reading of barcode data. do.

In order to achieve the above object, the present invention provides a barcode data reading method for reading data marked with barcodes, in which the barcodes are arranged at predetermined intervals according to the number of barcodes, and the barcode data is read. The time required from the start to reading the first barcode and/or the time required to read the adjacent barcode is measured, and the required time is compared with a reference time preset according to the number of barcodes. Accordingly, it is determined whether or not the number has been accurately read.

Next, preferred embodiments of the barcode data reading method according to the present invention will be described in detail with reference to the accompanying drawings.

In FIGS. 1a to 1d, reference numerals 10a to 10d indicate barcode data, and the barcode data 10a to 10d are 1 engraved at specific positions on the workpiece surrounded by imaginary lines A to D.
It is marked with one or more barcodes 12. That is, this barcode 12 is
As shown in the figure, these are V-shaped grooves carved on the surface of the workpiece 14, and four types of barcode data 10a to 10d are configured depending on the number of the grooves. In addition, barcode data 10a to 10d
The barcodes 12 constituting the barcode are arranged from line A toward line B at predetermined intervals P ₁ , P ₂ , and P ₃ corresponding to the number of barcodes 12 . Here, since the barcode data 10a has one barcode 12, the interval _P2 is zero.

Barcode data 1 configured in this way
0a to 10d are beam sensors 16 shown in FIG.
read by. In this case, the beam sensor 16 includes, for example, a light-emitting element such as a light-emitting diode, a light-receiving element such as a phototransistor, and an optical fiber (not shown) that optically connects the optical path thereof. On the other hand, it travels at a constant speed in the direction of arrow X while maintaining an inclination angle of 45 degrees. When the beam emitted from the light emitting element is reflected by the V-shaped barcode 12 engraved on the workpiece 14 and received by the light receiving element via an optical fiber (not shown), the beam sensor 16 performs control as described below. A high level pulse signal is output to the circuit, and when no light is received by the light receiving element, the pulse signal becomes a low level state. FIG. 2 shows the relationship between the position of the beam sensor 16 and the pulse signal in this case.

Next, a method of reading barcode data 10a to 10d configured as described above will be explained based on the control circuit shown in FIG. 3 and the flowchart shown in FIG. 4.

First, the beam sensor 16 is moved to the position of line A of the barcode data 10a to 10d marked on the workpiece 14 by an orthogonal coordinate type robot (not shown). When the beam sensor 16 reaches line A, a high-level synchronization signal S is output from the orthogonal coordinate robot to the CPU 22 of the microcomputer 20 forming the control circuit (STP1).
Upon receiving this synchronization signal S, the CPU 22 starts counting time using an internal timer (not shown) (STP2). Thereafter, the CPU 22 performs its control calculation operation according to the program installed in the ROM 23 in advance.

At the same time as the synchronization signal S is output, the beam sensor 16 runs at a constant speed from line A to line B of the barcode data 10a to 10d, and when it reaches the barcode 12, as shown in FIG. The sensor amplifier 24 transmits high-level pulse signals.
Output to. The sensor amplifier 24 is the beam sensor 1
6 and outputs the pulse signal to the CPU 22 via the sensor interface (STP3).

On the other hand, the CPU 22 counts the number of barcodes 12 according to the pulse signal input when the beam sensor 16 passes over the barcodes 12, and calculates the passing time of each barcode 12 (STP4, STP5). The above operations of Steps 4 and 5 are repeated until the beam sensor 16 reaches line B of the barcode data 10a to 10d and the synchronization signal S becomes low level (STP6). Here, the number of barcodes 12 is incremented by 1 in response to the rise of a pulse signal input when the beam sensor 16 passes the barcode 12, and is stored in a predetermined register. In addition, as shown in Figure 5, the barcode passage time includes the time from the rise of the synchronization signal S to the rise of the first pulse signal, the time from the rise to the fall of each pulse signal, and the time from the rise of the last pulse signal. The time t ₁ to t ₉ from the falling edge to the falling edge of the synchronization signal S is calculated from the time count value of the internal timer and stored in a predetermined register.
Here, FIG. 5 shows a time chart when the barcode data 10d is read by the beam sensor 16.

In this way, when the synchronization signal S becomes low level, the CPU 22 ends the time counting operation (STP7). Next, the CPU 22 calculates the barcode passing times t ₁ to t ₉ stored in each register.
Set the time period during which the pulse signal is at high level in advance.
Predetermined pulse width 10msec stored in RAM28
(See Figure 6a), anything less than 10 msec is removed as noise as shown in Figure 6b (STP8). In this case, the number of barcodes counted in step 4 is subtracted by the number of pulse signals removed in step 8. Further, a pulse signal having a pulse width of 100 msec or more (see FIG. 7a) is assumed to indicate that the barcode 12 is damaged due to crushing, etc., and is removed as shown in FIG. 7b (STP9). In this case as well, the number of barcodes is subtracted by the number of pulse signals removed in step 9.

After the above operations are completed, the barcode passing time
t ₁ to t ₉ are converted into central transit times T ₁ , T ₂₀ , T ₂₁ , T ₂₂ , and T ₃ of each pulse signal shown in FIG. 5, respectively (STP10). In this case, for example, T ₁ can be determined as T ₁ =t ₁ +t ₂ /2. Below, T ₂₀ , T ₂₁ ,
T ₂₂ and T ₃ are calculated in the same way. These times are stored in respective predetermined registers. In this case, the barcode passing times t ₁ to t ₉ are converted to the time between the centers of the pulse signals, so that detection errors due to the engraving accuracy of the barcode 12 engraved on the workpiece 14 are averaged and stabilized. data can be obtained.

Next, a determination algorithm previously stored in the RAM 28 is selected according to the number of barcodes counted in step 4 (STP11). That is, this judgment algorithm uses the time _T1 from when the synchronization signal S is output until the beam sensor 16 outputs a pulse signal and the time required until the beam sensor 16 reads the next barcode 12.
Each tolerance of T ₂₀ , T ₂₁ , and T ₂₂ (hereinafter referred to as T ₂ ) is set for each of the barcode data 10a to 10d, an example of which is shown in FIG.

In FIG. 8, the allowable time range of time T ₁ from the output of the high-level synchronization signal S to the detection of the first barcode 12 is shown by the white bar-shaped area,
Further, the allowable time range of time T ₂ from when the beam sensor 16 detects a barcode 12 to when it detects the next barcode 12 is shown by a bar-shaped region with diagonal lines. That is, in accordance with this determination algorithm, it is determined whether the respective transit times T ₁ and T ₂ of the barcode 12 by the beam sensor 16 are within a predetermined tolerance range (STP12). For example, when there are four barcodes 12, the allowable range of _T1 is between 15 msec and 87 msec, and the allowable range of _T2 is between 49 msec and 104 msec, as shown in FIG. Therefore, if both of these conditions are met at the same time, it is determined that the barcode 12 has been read correctly (STP13), and the LCD interface 30
The barcode 12 is displayed by the liquid crystal display 32 through the
Display the number of pieces or the product number etc. corresponding to the number of pieces. Further, if the values of T ₁ and T ₂ are outside the allowable range of the determination algorithm, it is determined that a reading error has occurred in the barcode 12 (STP14), and a warning is displayed on the liquid crystal display 32.

On the other hand, if the barcode data 10a to 10d are read normally, the data is displayed on the liquid crystal display 32, and the assembly robot 36 is operated via the robot interface 34 to read the barcode. Assembling work between products is performed according to data 10a to 10d. That is, for example, a workpiece corresponding to the barcode data 10a to 10d, for example, is assembled by the assembly robot 36.
The bearing is gripped and installed at a predetermined location, such as in a cylinder block.

As described above, according to the present invention, data regarding a product is indicated by the number of barcodes, and the barcodes are arranged at intervals corresponding to the number of barcodes, and the number and spacing of the barcodes are read, and the intervals between the barcodes are read. It is determined whether or not the data is within an allowable range of data set in advance according to the barcode. Therefore, if the interval is within the allowable range, it can be determined that the number of barcodes read is the correct value, and if it is outside the allowable range, it can be determined that the barcode data is missing or missing. It can be determined that there is a failure and the barcode is not being read accurately. As a result, it is possible to prevent misreading of barcodes marked on products and always obtain highly accurate reading results.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and changes in design can be made without departing from the gist of the present invention. Of course.

[Brief explanation of the drawing]

Figures 1a to d are explanatory diagrams of the structure of barcode data used in the barcode data reading method according to the present invention, respectively, and Figure 2 is a barcode and its detection sensor used in the barcode data reading method according to the present invention. 3 is a block diagram of a control circuit used in the barcode data reading method according to the present invention, FIG. 4 is a flowchart showing the barcode data reading method according to the present invention, and FIG. 5 is a block diagram of the control circuit used in the barcode data reading method according to the present invention. A time chart showing the relationship between the synchronization signal and the pulse signal from the beam sensor in the barcode data reading method according to the invention, FIGS. FIGS. 7a and 7b are time charts showing pulse signals after the correction, and FIGS.
The figure is an explanatory diagram showing a determination algorithm in the barcode data reading method according to the present invention. 10a-10d...barcode data, 12...
...Barcode, 14...Work, 16...Beam sensor, 20...Microcomputer.

Claims (1)

[Scope of Claims] 1. In a barcode data reading method for reading data marked with a barcode, the barcodes are arranged at predetermined intervals according to the number of barcodes, and from the start of reading the barcode data, the first barcode is read. By measuring the time required to read a code and/or the time required to read an adjacent barcode, and comparing the required time with a reference time set in advance according to the number of barcodes, the number of barcodes is determined. A barcode data reading method characterized by determining whether or not a barcode has been read accurately. 2. In the method described in claim 1,
A barcode data reading method comprising generating a synchronization signal at the start of reading barcode data, and measuring the time from generation of the synchronization signal to reading the first barcode. 3. In the method described in claim 1,
A method for reading barcode data, in which an optical sensor is run at a constant speed, the barcode is detected from changes in the amount of light reflected from the barcode data, and the required time is measured. 4. In the method described in claim 1,
The standard time has a predetermined tolerance range, and the quality of the barcode is determined based on whether the required time is within the tolerance range.