Glossary
Appendix D
D-4
Burn-In
The operation of a unit, at elevated temperatures, prior to its application
with the objective of stabilizing its characteristics and detecting
early failures.
Bus
(1) One or more conductors considered as a single identity that
interconnect various parts of a system. For example, a data bus or address
bus. (2) An electrical channel used to send or receive data.
Byte
Eight consecutive bits.
Cascading
(1) A programming technique that extends the ranges of timer and/or
counter instructions beyond the maximum values that may be accumulated
in a single instruction. (2) Using the output of a PID loop as a setpoint.
Central Processing Unit (CPU)
The circuits in a processor that control the interpretation and execution of
the user program stored in processor memory.
Channel Timeout
The time a device allows between operations before terminating
communication on a channel.
Character
One symbol of a set of symbols which normally include both alpha and
numeric codes plus punctuation marks, and other symbols which may be
read, stored, or written.
Chassis
A hardware assembly used to house devices such as I/O modules, adapter
modules, processor modules, power supplies, and processor.
Clear
To return a memory to a non-programmed state; erased.
Clock
(1) A pulse generator which synchronizes the timing of various logic
circuits. (2) Circuitry used to measure time.
Clock Rate
The speed (frequency) at which the processor operates, as determined by
the time elapsed as words or bits are transferred through internal
logic sequences.
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