Bus Mastering

On high-bandwidth buses, a great deal of information flows through the channel every second. Normally, a processor is required to control the transfer rate of this information. In essence, the processor acts as a middleman that we should cut out to perform the transfer directly for more efficiency. This is done by having capable devices that take control of the bus and do the work themselves; referred to as bus masters. In theory, the processor can handle multiple tasks simultaneously; though in reality there are several complicating factors. In order to do bus mastering properly, a facility to arbitrate requests to "take over the bus" must exist, which is provided by the chipset. Bus mastering is also called a "1st party" DMA, since the work is controlled by the device doing the transfer... ...read more.

PAC in MA (Machine Automation) Applications

Compared to existing control systems, PAC is a much better choice for some applications. One such example would be small DCS, though the control applications in this industry are very high-risk, and our products are not intended for this market. But there are industrial applications which require control systems with high computing ability and a flexible communication interface which are suitable for the PAC. Machine Automation, which has very complex control requirements, is a good example. It combines interlocking action with digital I/O, motion control & position control with pulse I/O, and safety and condition control with analog I/O. It also combines logic and computing ability together to handle unique applications. Such kinds of applications simply cannot be satisfied by a PLC because of their requirement for high computing ability. A rich communication interface option for system integration is also required because machines are used in different vertical markets. The above requirements are typical features of PC-based technology, and so a PC-based station embedded with control software would be the perfect solution.......read more.

Related article: Why create the PAC (Programmable Automation Controller)?