Characteristics and Functions of Barcode Auto-ID Technology

Because a bar code label may be at an angle to the laser beam, one laser beam cannot scan the complete bar code, for this reason, Accu-Sort has developed data reorganization technology, also known as DRX (Data Reconstruction). Since the goods are constantly moving, each scan of the laser beam will have new data (see Figure 2), the core of the DRX technology is to compare the data obtained from each scan with the data from the previous scan, to find the same intermediate part, and then add new content. Although the information obtained from each scan is incomplete, with DRX, complete information can still be obtained.

Various Omni-directional Scanners (X, Dual X, Quad X, Pattern)

When a single line laser beam is used, even with DRX technology, the angle of declination between the laser beam and the barcode still cannot be greater than 45 degrees. This is because as the declination angle increases, the overlap in data reorganization decreases, resulting in a lower read rate. In the extreme case, when the declination angle reaches 90 degrees, the overlapping part is zero, and reading is no longer possible. For this reason, an X-pattern laser beam scanner was developed. This scanner can read barcode labels in any direction, because there is always a laser beam can scan the barcode with a small angle of deviation, to get a high reading rate. If not only the direction of the bar code deviation is large, but also the position of the bar code deviation is also large, the laser beam is a double X or quadruple X pattern scanner, in order to improve the reading rate (see Figure 3, 4, 5).

Technologies such as dual-depth-of-field, triple-depth-of-field, and dynamic focusing

The laser scanner basically consists of two main parts. The optical system directs a laser beam at the barcode and then collects the light signal reflected back from the barcode. The electronic system converts the optical signals into electrical signals, which are then decoded according to a prescribed code system to obtain character information.

Since it is an optical system, there is the issue of focal length. A relatively clear reflected light can be collected at a certain distance. This is the depth of field of the scanner. But in some material handling systems, due to the size of the goods gap, the required depth of field is too large, with a fixed focal length of the scanner can not be adapted. To this end, Accu-Sort developed a double depth of field and triple depth of field scanner (see Figure 6). A number of photoelectric sensors are to be set up in the system. When the goods pass through the scanner, the photoelectric sensor determines the distance of the surface of the goods away from the scanner. This distance signal causes the optical system of the scanner to adjust to the required depth of field area. The latest technology, however, is like a zoom lens in a camera, which can be infinitely adjusted, i.e., dynamic focusing without setting up the photoelectric sensors.

Laser diode with thermoelectric cooling for improved lifetime

The laser diode is the main component of the scanner, and its lifetime is temperature dependent. When the scanner has to work for a long time in a higher temperature environment, how to reduce the temperature is a crucial issue. Currently, thermoelectric cooling technology has been developed, the laser diode temperature can be controlled at about 25 ℃, thus improving the service life of the scanner.

Transferring information from multiple scanners with multiplexers improves reliability

In some material handling systems, such as airport baggage handling systems, the orientation of the bar code labels is random, and can be in any direction up, down, left, right, forward or backward. For automatic recognition, 8 to 12 scanners need to be placed to form a channel. As long as there is a scanner in this channel group can read the bar code label, it can be effectively sorted by PLC (Programmable Logic Controller). The key is how to ensure the reliability of these scanners and PLC communication. If each scanner with the PLC through the connection, in case of communication line interruption, the entire baggage sorting system will be paralyzed. In order to improve the reliability of the system, you can use the multiplexer to transfer information. Multiple scanners can be connected to one or two multiplexers, which summarize the information read and then connected to the PLC. This configuration has become a standardized requirement for airport baggage systems.

Self-diagnostic software package has become an important means of improving the performance and reliability of the scanner

After the use of barcode automatic identification technology in the material handling system, the reliability of the scanner directly affects the reliability of the entire system. To this end, a self-diagnostic software package has been developed. It runs in the Windows environment, at any time to collect the scanner working condition of the statistical information and maintenance data, including read rate, laser diode, motor, decoding line, photoelectric tube and other work and bar code in the scanner field of view of the position of the goods between the spacing and so on. Once found with the normal value of a large deviation, it will issue a warning, the need for scanners or bar code labels to the quality of a more detailed examination, so as to avoid problems with the reliability of the system.

Matrix scanning technology

In the material handling system sometimes not only need to identify the whole box, but also need to identify the goods inside the box. For example, in a shoe distribution operation, a box can contain shoes of different specifications and sizes. Each pair of shoes has its own barcode label on the box. When the box through the scanner, the matrix of bar codes are read one by one, so as to achieve the inspection of the shipped box is