Handheld barcode scanners have always been a key part of the application of automatic identification technology and have always been a decisive factor in bar code systems in the industrial and application fields. Today's manufacturers have offer a wide range of performance-to-price products for a variety of consumer needs.
The three main types of handheld barcode scanners are contact stylus, CCD reader (image barcode scanner), and laser scanner. When considering which scanner is more suitable for your needs, you need to first understand some of the main features of the handheld barcode scanner, namely 1) light source and image barcode acquisition device; 2) decoding equipment; ) Interface mode.
The types of three bar code scanners are determined by their scanning engine. The scanning engine is used to generate light and scan bar codes. The scanning engine of the light pen uses light-emitting diodes (LEDs), and the CCD bar code scanner uses electronic coupling devices. (CCD), the scanning engine of the laser barcode scanner is a visible laser diode (VLD). The scan engine is a major factor influencing the price/performance ratio of a handheld bar code scanner and determines its suitability for a variety of uses. After you understand the difference, you can choose a handheld barcode scanner with the best performance and value.
Successfully selecting a bar code scanner that matches the target needs, the user has three main criteria: working distance, label size, and bar code density. Working distance refers to the distance between the scanner and the label during scanning. The scanning distance can be from zero (contact) to several feet. The scanning distance is determined by the barcode scanner; the label size refers to the entire width of the scanned barcode; the barcode density refers to the energy. The width of the smallest or empty module that satisfies reading. These three factors are related to each Other. For example, the label size and the bar code of the bar and the empty module can also support a larger scanning distance. Light pens, CCD bar code scanners, and laser bar code scanners have different performances, and have different price points and usage periods. In each aspect, users must make different considerations.
Working distance (depth of field)
The depth of field of the barcode scanner must be clearly defined. Does the operator touch the bar code scanner to the label surface or keep it at a distance? In general, contact or close-range scanning is used in retail, office, and factory applications, while long-distance scanning is typically used in warehouse, distribution, and transportation applications.
The depth of field of the three types of bar code scanners is very different. It can be seen from their naming that the contact type light pen needs to be in contact with the label surface; the working distance of the CCD bar code scanner is limited to 0-30cm, but the latest production of CCD bar code The scanner has effectively extended the depth of field to 60 cm); the laser bar code scanner has the longest depth of field, between (20-100 cm), and some special laser guns dedicated to scanning large bar codes can reach a few feet.
The difference in depth of field can be reflected by the price of the barcode scanner. The light pen is usually the most economical bar code in terms of cost and life cycle. The laser gun is the most expensive, and the price of the CCD bar code scanner is between the two.
2. Label size / label density
The label density refers to the minimum width of a strip or empty cell, measured in thousandths of an inch, or "mil". For linear and one-dimensional bar codes, the size of the label is considered to be the width of the label. High-density barcodes (below 7 mils) need to be scanned at closer distances, and low-density barcodes (above 15 mils) can be scanned at longer distances.
When selecting a CCD barcode scanner, be sure to know the entire width of the scanned barcode. In most cases, the maximum width of the barcode that the CCD barcode scanner can scan is limited by the width of the scanner's opening. Some special barcode scanners for reading large scales need to be specifically designed. Since the light produced by the light pen and laser gun can move on the surface of the bar code, both readers can scan a wider bar code.
If you decide to choose a stylus, you must consider the aperture of the stylus on the hardware side. The width of the aperture is approximately equal to the width of the narrowest strip or space of the X-dimensional barcode to be scanned. If the aperture is too large, the adjacent bar code will appear in the scanning window during scanning, making scanning more difficult. If the aperture is too small, the scanner will treat some printed errors on the bar code as the bar code should not exist. Strip or empty, causing the scan to generate an error.
3. Image decoding
Once the scanner's beam and recognition system captures a bar or empty cell, the information must be converted to a symbol that the computer system can recognize. This process is called decoding. The decoding function module can automatically identify the type of the scanned barcode and load the corresponding decoding algorithm to decode the barcode on the label.
The decoded information is formatted into standard RS-232 serial port data or converted to keyboard commands for transmission to the host computer system. The decoded information is transmitted to the RS-232 communication interface through a cable, and the keyboard data is transmitted to the keyboard port of the terminal through a "Y" cable.
"Interface" is used to indicate the connection between the barcode scanner and the host or terminal. The serial port inserts the scanned data into the RS-232 signal between the host or the terminal, and the keyboard port treats the data as a string of keyboard signals. Through the programmed software, the bar code scanner can scan the bar code menu to select the parameters of the terminal and interface.
A few years ago, the decoding and communication functions of the barcode scanner were performed by separate devices. The barcode scanner outputs a laser calibration signal (HHLC) or a light pen simulation signal to an external decoding box, and the decoding and transmission functions are performed by the decoding box. Now, manufacturers of barcode scanners have integrated the decoding components of the three types of barcode scanners into one part, the Decode Output Scanner (DOS). The Decode Output Scanner uses a plug-in that provides exactly the same performance as the code box and is less expensive.
Additional decoding ports are still required when two or more different types of scanning devices operate in their respective decoding states or require an auxiliary port (for integrated measurement, printing, or other I/O devices). But from the convenience of integration and low system cost, this integrated decoding scanner is still an excellent choice.
4. Interface device
After the data on the tag is decoded, it must be passed to the host computer system. The functions of the serial port and keyboard port for formatting data and output have been described above. Of course, the barcode scanner must be physically connected to the host computer system, so the consumer needs to identify the type of physical interface of the PC or system. Manufacturers' handheld barcode scanners support hundreds of terminal types, as well as hundreds of interface lines, allowing users to order the appropriate interface lines as needed.
Since the decoded output scanner can support many kinds of terminal interfaces with one component, some manufacturers of CCD and laser handheld scanners have standardized a common interface line scheme, so that users do not need to reserve a large number of interface lines, and use a common interface line. It can support both CCD scanners and laser scanners while saving time and money.
The three types of handheld bar code scanners, stylus, CCD scanner and laser scanner, have superior performance and price ratios in applications. After learning about some of the main features and price differences, I hope you can choose the most suitable handheld barcode scanner.
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