Introduction to common functions of handheld scanners

The handheld scanner is a purely bar coded device, and the data collector is a combination of a PC that can be used for mobile batch or timely data transfer equipment. The two types of equipment are introduced as follows:

First, handheld scanner

        A handheld bar code scanner, also commonly referred to as a bar code scanner, is a reading device for reading information contained in a bar code. The layout of the bar code scanner is usually the following parts: light source, take-over assembly, photoelectric conversion component, decoding circuit, computer interface. The basic reason of the barcode scanner is that the light recovered by the light source is irradiated under the bar code mark, and the reflected light returned from the optical system is imaged on the photoelectric converter, so that the electric signal is generated, and the flag is generated. After the signal is amplified, the analog voltage is generated. It is proportional to the light reflected from the bar code mark, and then filtered and shaped to form a square wave signal corresponding to the simulated signal. The encoder is interpreted as a computer that can indirectly recognize the remaining digital signals.

        According to the scanning method, it can be divided into: CCD barcode scanner, laser handheld scanner, full-angle laser scanner, and the like.

        (1) The CCD barcode scanner uses the photoelectric coupling (CCD) principle to stop imaging the barcode printing pattern and then decode it.

        Advantages: No shaft, long application life; cheap price. When choosing a CCD scanner, note that since the imaging principle of the CCD is similar to a camera, if the depth of field is to be increased, the lens should be increased in response, so that the CCD is too large in size and inconvenient to manipulate. An excellent CCD should be readable without the need for a bar code, and it is moderately sized and comfortable to operate.

        Resolution: If the CCD resolution is to be improved, the unit elements of the photosensitive element at the imaging location must be increased. The low-cost CCD is usually 500 pixels (pixel), reading EAN, UPC and other trade codes have been sufficient, it will be harder to deal with the rest of the code system. The mid-range CCD is more than 1024 pixels, and some even reach 2048 pixels, which can distinguish the bar code with the narrowest element of 0.1mm.

        (2) The laser hand-held scanner is a single-line scanner that uses a laser diode as a light source. It is important to have both a mirror type and a dither type.

        When trading companies choose laser scanners, the most important thing is to pay attention to the scanning rate and resolution, and the depth of field is not the crux of the problem. As the depth of field increases, the resolution will be greatly reduced. An excellent handheld laser scanner should have a high scan rate and a high resolution over a fixed depth of field.

        (3) The full-angle scanner is a bar code scanner that refracts laser light or multiple scanning lines through the optical system of the process. The important goal is to increase the labor of the bar code when the bargaining staff enters the bar code data. Scan line spot distribution:

        1. There are multiple parallel lines in one direction;

        2. There are multiple scan lines at a certain point;

        3. The probability of interpretation of each point in a certain spatial range tends to be equal.

        Second, the data collector

        There are two types of data collectors, one for batch processing data collection and one for wireless data collectors, which are based on the growth of wireless modules based on the former.

The total hardware features of the data collector:

        1, CPU processor: With the development of digital circuit technology, data collection terminals mostly adopt 16-bit or better 32-bit CPU (central micro-processor). The advancement of indicators such as the number of CPUs and the main frequency makes the data collector's data collection and disposal ability and the processing rate request higher and higher, and the user's on-site effect is improved.

        2, handheld terminal memory: Most products today adopt FLASH-ROM + RAM type memory. Important files such as operating system, application method, and font file are stored outside the FLASH-ROM, and even if it is not powered for a long time, it can be adhered to. The collected data is stored outside the RAM, and the battery and backup battery are attached to the data. Due to the faster read and write speed of the RAM, the rate of manipulation can be guaranteed. The size of the memory capacity of the handheld terminal determines the amount of data that can be handled at one time.

        3. Power consumption: including the power consumption of the bar code scanning equipment, the power consumption of the performance screen, the power consumption of the CPU, and the like. Supported by the battery.

        4. Input equipment: It includes two methods: barcode scanning input and keyboard input.

        5, performance input: Most of the current data collectors have large-screen LCD performance screen. It can display various kinds of user information in Chinese, English and graphics. At the same time, there are stricter requests for performance accuracy and industrial functions of the screen.

        6. Communication ability with the computer system: As an extension of the computer collection system, the data collected by the handheld terminal and the disposal result should be exchanged with the computer system.

        7, handheld barcode scanner peripheral equipment driver can:

        The serial port and infrared port of the data collector can be connected to various standard serial port equipments, or through serial-to-parallel conversion, it is possible to connect various types of parallel port equipment. Including: serial parallel port printers, modems, etc., to complete the various functions of the computer.

        Self-reliance features of wireless data collectors:

        The advantage of portable data collectors against traditional manual manipulation was once unknown, but a more advanced device, the wireless data collector, further expanded the functionality of the popular portable data collector. Wireless data collectors are mostly portable. In addition to the advantages of a normal portable data collector, and the advantages of an online data collector, communication with the computer is done via radio waves, which can be collected on site. The data arrived is transmitted to the computer in time. Compared with the popular portable data collector, the effect of the operator is further improved, and the data is transferred from the original local verification and retention to the control system and transmitted in time.

        The wireless data collector is called wireless, because it does not need to stop the communication station and the PC to stop data exchange like the popular portable data collector, but it can stop the timely data indirectly through wireless collection and PC and server. Communication. To apply a wireless handheld terminal, you must first establish a wireless collection. Wireless collection equipment - Access Point is equivalent to a bridge connecting wired LAN and wireless network. It is connected to wired collection (Ethernet or Token Network) via twisted pair or coaxial cable. The terminal then stops data exchange via wireless communication with the AP and the server of the local area network.

        Wireless data collector communication data is time-sensitive and efficient. The wireless data collector indirectly stops the data exchange with the server, and the data is transmitted in a timely manner. The data is retrieved from the wireless data collector, and the AP that arrives at the wireless terminal location channel is wirelessly collected, and the AP transmits the data to the wired LAN network through the twisted pair or coaxial cable that is connected, and the data arrives at the NIC port of the server. Enter the server, and then the server will go to the wireless terminal through the original road. All data is transmitted in TCP/IP communication protocol. It can be seen that all the manipulated data of the operator on the wireless data collector enters the back-end database at the first time, which means that the wireless data collector extends the database information system to the hands of each operator.

        The wireless hardware collector's product hardware skills are equivalent to portable requests, including CPU, memory, screen performance, input equipment, input equipment, and more. In addition, the analogy is the wireless communication mechanism. At present, there are two kinds of wireless frequency hopping techniques and wireless spread spectrum techniques. It should be said that the two techniques have their own advantages and disadvantages. However, in terms of popular warehousing logistics and wholesale applications, frequency hopping techniques can be stronger due to their anti-interference and data transmission is stable, so adoption is more common.

        Each wireless data collector is a collection node with its own IP address, through the wireless landing point (AP), to complete the timely data exchange with the collection system.

        The connection between the wireless data collector and the computer system basically adopts three methods:

        1, TELNET terminal simulation convergence: Under this type of method, the wireless data collector itself does not need to open up the application law. Just go through the TELNET service to the application server, and run the French under the long-distance server. Under this type of method, communication is definitely less effective because a large number of terminal emulation throttled data streams are exchanged between the wireless collector and the server. However, since there is no need to open up the application law on the data collector, it is absolutely simple and easy to update the system.

        2, the traditional C / S layout: the wireless data collector as the CLIENT end of the system, the collector below the user's application process request to stop the French development. The development of the platform is the same as that of the portable, and there are differences based on the differences. Under such methods, the data collector and the communication server only need to exchange the collected data information, the amount of data is small, and the communication response is high. However, like the portable data collector, each wireless data collector must be equipped with an application method, which is more troublesome for the application of the previous application.

        3, B / S layout: embedded browser under the wireless data collector, through the HTTP protocol and the application server to stop data exchange. This kind of method has higher requirements for the wireless data collector system. The products based on the WinCE platform are definitely easier to accomplish, such as the SYBMBOL company's several equipment.