During the early years of microprocessors, there were few engineers with
education and experience in the applications of microprocessor technology.
Now that microprocessors and microcontrollers have become pervasive in so
many devices, the ability to use them has become almost a requirement for
many technical people.
The analog output modules convert digital signals from the PLC into analog signals for the process. The modules feature the following: Resolution from 12 to 15 bit Various voltage and current ranges: The ranges are set independently for each channel using parameterization software. Interrupt capability: The module transmits diagnostic alarm messages to the controller’s CPU in the event of errors.
Over the years, the role of the computer auditor has
changed to being more consultative and value
adding. Clearly, where a new system is being
developed, it is more cost effective for audit
comments to be provided prior to a system being
implemented, when improved security and control
features can be included more easily and cheaply.
Similarly, although computer auditors regularly
undertake audits of say logical access controls, there
is considerable scope for computer auditors to be
involved in the design of those components.
Sau khi học xong chương này người học có thể: nắm nguyên lý cấu tạo và đặc điểm của thiết bị I/O, nhiệm vụ và yêu cầu của thiết bị I/O, cách giao tiếp giữa CPU và thiết bị I/O, hiểu các bước trong quá trình ngắt quãng, nắm được cơ chế DMA. Mời các bạn cùng tham khảo.
The microcontroller is an exciting new device in the field of electronics
control. It is a complete computer control system on a single chip.
microcontrollers include EPROM program memory, user RAM for storing
program data, timer circuits, an instruction set, special function registers,
power on reset, interrupts, low power consumption and a security bit for
software protection. Some microcontrollers like the 16F818/9 devices include
on board A to D converters.