Functional Characteristics Of Bar Code Scanner
Aug 17, 2018

Barcode scanning guns were born from the very beginning, and they have been promoted into all walks of life with their own unique advantages. In today's rapid economic development, the technological innovation of scanners is changing with each passing day, but all the technical foundations are the same. It does not change its ancestry. We do a comprehensive analysis of the characteristics of the scanner. We summarize it in three areas.

First, the various styles of barcode scanners

1, SCSI (small computer standard interface)

The maximum number of connected devices on this interface is eight. Usually, the maximum transmission speed is 40M/S, which is faster and generally connects to high-speed devices. The installation of SCSI devices is more complicated. Generally, a SCSI card is added to the PC, which is easy to generate hardware conflicts, but it is powerful.

2, EPP (Enhanced Parallel Interface)

An enhanced bidirectional parallel transmission interface with a maximum transmission speed of 1.5Mbps. The advantage is that there is no need to use other cards in the PC, unlimited number of connections (as long as you have enough ports), the device is easy to install and use. The downside is that the speed is slower than SCSI. This interface replaces the SCSI interface in the low-end and low-end performance requirements due to its ease of installation and use.

3, USB (Universal Serial Bus Interface)

Up to 127 peripherals can be connected. The current USB 1.1 standard has a maximum transfer speed of 12 Mbps and has a secondary channel for transmitting low-speed data. In the future, if you have a USB 2.0 standard barcode scanner speed may be extended to 480M / s. Hot pluggable, plug and play. The bar code scanner of this interface has become popular with the establishment and promotion of the USB standard under the push of Intel.

4, PS2 (keyboard interface)

Similar to USB usage, you need a smart head to convert it, which is usually included in the scanner you usually purchase. There are still many companies using the PS2 interface.

Second, the parameter type of the barcode scanner

1, scanner resolution

For barcode scanning systems, the resolution is the correct detection of the width of the narrowest stripe read. English is MINIMALBARWIDTH (abbreviated as MBW). When selecting a device, it is not the higher the branching rate of the device. The scanner with the corresponding resolution should be selected according to the barcode density used in the specific application. In use, if the resolution of the selected device is too high, the stain on the bar, deinking, etc. will have a more serious impact on the system.

2, scanner depth of field

Scanning depth of field refers to the difference between the farthest distance that the scanning head allows to leave the surface of the barcode and the closest point to which the scanner can approach the surface of the barcode, ensuring reliable reading, which is the effective working range of the barcode scanner. Some bar code scanning devices do not give a scanning depth of field indicator in the technical specifications, but give a scanning distance, that is, the shortest distance that the scanning head allows to leave the surface of the barcode.

3, scanner scan width (SCANWIDTH)

The scan width index refers to the physical length value of the bar code information that the scanned beam can read over a given scan distance.

4, scanner speed (SCANSPEED)

The scanning speed is the scanning frequency of the scanning beam on the scanning track per unit time.

5, scanner recognition rate

The primary recognition rate represents the ratio of the number of labels read in the first scan to the total number of scanned labels. For example, if the information for each barcode label read needs to be scanned twice, the recognition rate is 50%. From the practical point of view, of course, I hope that every scan can pass, but unfortunately, due to a variety of factors, it is impossible to achieve a recognition rate of 100%.

6, scanner error rate

The bit error rate is an extremely important test indicator that reflects the misidentification of a machine-recognizable tag system. The bit error rate is equal to the ratio of the number of false recognitions to the total number of recognitions. For a bar code system, the bit error rate is a more serious problem than the low recognition rate.

Third, the advantages of barcode scanner

1. Fast input speed: Compared with the keyboard input, the bar code input speed is 5 times of the keyboard input, and can realize "instant data input".

2, high reliability: keyboard input data error rate of three percent, using optical character recognition technology error rate of one in ten thousand, and the use of bar code technology error rate is less than one in a million.

3, the amount of information collected is large: the traditional one-dimensional bar code can be used to collect dozens of characters of information at a time, the two-dimensional bar code can carry thousands of characters of information, and has a certain automatic error correction capability.

4. Flexible and practical: Bar code identification can be used as a means of identification alone, or it can be combined with related identification equipment to realize automatic identification, and can also be connected with other control equipment to realize automatic management.

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