3HAC025784-001 DSQC651A | ABB I/O unit

Description

General Information

• Product ID:3HAC025784-001
  
• ABB Type Designation:31x19x8,5
  
• Catalog Description:DSQC 651A I/O Unit

I/O devices I/O devices can be broadly divided into two categories: block devices and character devices. Block devices store information in fixed-size blocks, each with its own address. The typical block size is between 512 and 65536 bytes. All transmissions are in one or more complete (contiguous) blocks. The basic feature of a block device is that each block can read and write independently of other blocks. Hard drives, Blu-ray discs, and USB drives are the most common block devices. Disks are recognized as block-addressable devices, Another class of I/O devices are character devices. Character devices send or receive a stream of characters in units of character, regardless of any block structure. Character devices are not addressable and do not have any seek operations. Printer, network interface, mouse (used as pointing device). Device controller I/O equipment is generally composed of two parts: mechanical parts and electronic parts. It is often possible to treat these two parts separately to provide a more modular and versatile design. An electronic component is called a device controller or adapter. The interface between the controller and the device is usually a very low level interface. For example, a disk can be formatted as 2 million sectors per track, 512 bytes per sector. What actually comes out of the drive, however, is a serial stream of bits, starting with a preamble, followed by 4096 bits in a sector, and finally a checksum, also known as Error-Correcting Code (ECC). The leading character is written when the disk is formatted and includes the number of cylinders and the sector number, sector size, and similar data, in addition to synchronization information. The task of the controller is to convert the serial bit stream into byte blocks and perform the necessary error correction. The byte block is usually first assembled bitwise in a buffer inside the controller, and then copied to main memory after verifying and verifying that the byte block is error-free. The controller of the LCD display is also a bit serial device.

Memory mapping I/O Each controller has several registers used to communicate with the CPU. In addition to these control registers, many devices have a data buffer that the operating system can read and write to. How does the CPU communicate with the device's control registers and data buffers? There are two alternative methods. 1. In the first method, each control register is assigned an I/O port number, which is an 8-bit or 16-bit integer. All I/O ports form I/O port space and are protected so that normal user programs cannot access them (only the operating system can access them). Using a special I/O instruction, such as IN REG, PORT, the CPU can read the contents of the control register PORT and store the result in the CPU register REG. Similarly, with: OUT PORT, REG, the CPU can write the contents of the REG to the control register. 2. The second method was introduced by PDP-11, which maps all control registers into the memory space. Each control register is assigned a unique memory address, and no memory is assigned to this address. Such a system is called memory-mapped I/O(memory-mapped I/0). In most systems, the address assigned to the control register is at or near the top of the address space. 3. How do these programs actually work? In each case, when the CPU wants to READ a word, either from memory or from an I/O port, it places the required address on the bus address line and then sets up a read signal on one of the bus control lines. 4. A second signal line is also used to indicate whether I/O space or memory space is required. If it is memory space, memory will respond to the request. If it is an I/O space, the I/O appliance will respond to the request. If there is only memory space, then each memory module and each I/O device will compare the address line to the address range it serves, and if the address falls within that range, it will respond to the request. Because there is absolutely no address assigned to both memory and I/O devices, there is no ambiguity and conflict. The two addressing controller schemes have different advantages and disadvantages

The company focuses on DCS, PLC, robot, large servo four systems

The main products are various modules/cards, controllers, touch screens, servo drivers Company advantage: Supply imported original products, professional production of spare parts One year warranty, fast delivery time, complete supply !！！ ① 24 hours email response (12 hours); ② For shipment outside Asia, please contact the seller.

ABB Related Products

【 Disclaimer 】 We sell new products and discontinued products, independent channels to buy such special products. Guizhou Yuanmiao Automation Equipment Co., Ltd. is not an authorized distributor, dealer or representative of the products featured on this website. All product names/product images, trademarks, brands and microlabels used on this Website are the property of their respective owners. Descriptions, depictions or sales of products with such names/images, trademarks, brands and logos are for identification purposes only and do not imply any association or authorization with any rights holder. This article is from the official website of Guizhou Yuanmiao Automation Equipment Co., LTD. Please attach this link:http://www.ymdcs.com/ABB/