User`s manual

64 PCL-848AB User's Manual
9. BUS TUTORIAL
9.1. General BUB DeBCriPtiOn
The IEEE-488 bus is easy to use and allows great flexibility in data communications
between independent devices. These features have made it one of the world’s most
popular methods for connecting multiple devices to one interface.
The IEEE-488 bus’s popularity comes from its ability to act as an interface between
the computer and the computer’s peripherals. Every interface should handle the
hardware book keeping and timing while maintaining four areas of compatibility
between the computer and its peripherals. These areas include:
Electrical - to insure the proper voltage and current requirements.
Mechanical - a connector to physically connect the computer to its peripherals.
Functional - hardware and software to convert computer data to bus data and vice
versa.
Operational - commands and data on the bus are interpreted in similar ways by all
devices in the system.
This interface card implements IEEE-488 interface standard and does all of these well.
Electrically, this card uses IEEE-488 bus drivers that are designed to drive long cables
and receive noisy data without error. The data, address, and control bus interface
between the board and the PC has been designed for minimum current loading and
maximum speed. Mechanically, it has a connector that is identical to all other
connectors of the IEEE-488 standard. This allows devices to be quickly and easily
added or removed from the system. The connector is designed to withstand over 1000
insertions and provide maximum electromagnetic radiation protection when used with
a shielded cable.
Functionally, this card provides the complete computer to peripheral interface by
using an IEEE-488 bus controller chip. The IEEE-488 bus chip provides complete
compliance with the latest update to the IEEE-488 standard. Full compliance with the
interface standard means that the PC can control any IEEE-488 compatible peripheral
or become a device that may be controlled by other computers. The PC can send data
to multiple devices simultaneously or instruct devices to send data to each without
supervision by the computer. Full compliance means that fourteen devices may be
attached to one interface card. Multiple inter face cards may be used in one PC.