Description
AD908CC Standalone I/O Processor
AD908CC provides many dedicated modules and function modules for various signals and applications in the industrial field, such as temperature, tension, stepper motor drive, oscilloscope, drum sequence generator signals, incremental pulse encoding signals, weighing signals and ultrasonic signals, power measurement and grid synchronisation, PWM outputs and so on. They will be various forms of field signals very convenient access to the PCC as the core of the digital control system, the user can be required to the application system I / O channel tens of points, hundreds of points or even thousands of points of expansion and networking. all digital inputs of the PCC are photocoupled isolation, the analogue inputs have been RC filtering, so it has a very good resistance to electromagnetic interference.
AD908CC Inside the PCC module, the data bus of the CPU is separated from the I/O bus and is configured with an independent I/O processor. The main CPU contains an independent Time Processing Unit (TPU), which handles simple or complex timing tasks at high speed without increasing the CPU load, and its reference timing frequency can be as high as 6.29MHz, so it is now widely used in frequency and phase measurements as well as PWM (Pulse Width Modulation) and other time processing occasions that require extremely high accuracy. The CPU’s main board is integrated with the CPU’s motherboard. In addition, the CPU’s motherboard integrates a variety of communication interfaces, and the PCC is also a highly open product configured with a variety of communication modules.
The AD908CC uses a single-task clock scanning or monitoring programme (except for certain high-grade PLCs, such as Siemens’ S7-300/400 series, Rockwell’s ControlLogix series, etc.) to handle the logic operation instructions of the programme itself as well as the state acquisition and refreshment of the external I/O channels, and the whole application programme is contained in a single cyclic cycle (as shown in Fig. 1) The entire application is contained in one cycle (as shown in Figure 1). However, in a control system, although there are some process quantities of high real-time requirements, but at the same time there are more process quantities of real-time requirements are not special, if the same refresh rate to deal with them is in fact a waste of system resources, and circular scanning mechanism also leads to the system processing cycle depends mainly on the size of the application program, such as the program is complex and large, the scanning cycle is inevitable If the programme is complex and large, the scanning cycle will be longer, which is undoubtedly contrary to the high real-time requirements of the I/O channels.