Rockwell Automation 1772-L8_LW_LWP_LX_LXP,D17726.5.8 User Manual - Manual (Page 439)

Glossary
Appendix D
D-20
Rack
An addressing concept equivalent to 128 discrete I/O.
Rack Fault
(1) A red diagnostic indicator that lights to signal a loss of communication
between the processor and any remote I/O chassis. (2) The condition
which is based on the loss of communication.
Read/Write Memory
A memory where data can be stored (write mode) or accessed (read mode).
The write mode replaces previously stored data with current data; the read
mode does not alter stored data.
Record
A group of data that is stored together and/or used together in processing.
A collection of related data is treated as a unit. See File.
Redundancy
The duplication of devices for the purpose of enhancing the reliability or
continuity of operations.
Redundant System
Two or more devices that actively control the outputs of a system. Each
device in the system votes on every control decision. If one device makes
a decision that does not agree with the decision made by the other devices,
it drops out of the loop and the others continue to control the outputs.
Register
A memory word or area used for temporary storage of data used within
mathematical, logical, or transferral functions.
Relay Logic
A representation of the program or other logic in a form normally used for
relays.
Remote I/O Processor
A processor system where some or all of the I/O racks are remotely
mounted from the processor. The location of remote I/O racks from the
processor may vary depending on the application and the processor used.
Also see Local I/O Processor.
Remote Mode Selection
A feature which allows the user to select or change processor modes of
operation with a peripheral device from a remote location.
Remote Programming
A method of performing processor programming by connecting the
programming device to the network rather than to the processor.
R