INTRODUCTION
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I-E96-217A
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GLOSSARY OF TERMS AND ABBREVIATIONS (continued)
Term
Definition
EWS
Engineering Work Station; an integrated hardware and software personal
computer system for configuring and monitoring INFI 90 modules.
Function Block
A function code located in the user defined memory of a multi-function pro-
cessor.
Function Code
An algorithm which defines specific functions. These functions are linked
together to form the control strategy.
Handshaking
The procedures and standards used by two computers or a computer and a
peripheral device to establish communication.
LED
Light Emitting Diode; the module front panel indicator that shows status and
error messages.
LSB
Least Significant Bit; the bit of a binary number that carries the least numeri-
cal weight.
MMU
Module Mounting Unit; a card cage that provides electrical and communica-
tion support for INFI 90 modules.
Module Bus
A peer-to-peer communication path for status and point data transfer
between intelligent modules within a process control unit.
MSB
Most Significant Bit; the bit of a binary number that carries the most numeri-
cal weight.
Parity Bit
An extra bit added to a byte, character or word to ensure that there is always
either an even number or odd number of bits, according to the logic of the
system. If, through a hardware failure, a bit should be lost in transmission, its
loss can be detected by checking the parity.
PCU
Process Control Unit; rack type industrial cabinet that contains master, slave
and communication modules, and their communication paths.
RAM
Random Access Memory; processor memory that has both read and write
capability. This memory is volatile; its contents are lost when power is
removed.
ROM
Read Only Memory; a special type of computer memory, permanently pro-
grammed with a group of frequently used instructions. It does not lose its
program when computer power is removed.
Serial Data
Data transmitted sequentially, one bit at a time.