Rockwell Automation 1756-XXXX ControlLogix Digital I/O Modules User Manual

Page 252

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252

Rockwell Automation Publication 1756-UM058G-EN-P - November 2012

Glossary

minor revision

A module revision that is updated any time there is a change to the module that
does not affect its function or interface.

multicast

Data transmissions that reach a specific group of one or more destinations.

multiple owners

A configuration set-up where multiple owner-controllers use exactly the same
configuration information to simultaneously own an input module.

network update time (NUT)

The smallest repetitive time interval in which the data can be sent on a
ControlNet network. The NUT ranges from 2 ms to 100 ms.

owner-controller

The controller that creates and stores the primary configuration and
communication connection to a module.

program mode

In this mode the following events occur:

Controller program is not executing.

Inputs are still actively producing data.

Outputs are not actively controlled and go to their configured

Program mode.

rack connection

An I/O connection where the 1756-CNB module collects digital I/O words into
a rack image to conserve ControlNet connections and bandwidth.

rack optimization

A communication format in which the 1756-CNB module collects all digital I/
O words in the remote chassis and sends them to controller as a single rack image.

remote connection

An I/O connection where the controller establishes an individual connection
with I/O modules in a remote chassis.

removal and insertion under power

(RIUP)

ControlLogix feature that allows a user to install or remove a module or RTB
while power is applied.

removable terminal block (RTB)

Field wiring connector for I/O modules.

requested packet interval (RPI)

The maximum amount of time between broadcasts of I/O data.

run mode

In this mode, the following events occur:

Controller program is executing

Inputs are actively producing data

Outputs are actively controlled

service

A system feature that is performed on user demand, such as fuse reset or
diagnostic latch reset.

system side

Backplane side of the interface to the I/O module.

tag

A named area of the controller’s memory where data is stored.

timestamping

A ControlLogix process that stamps a change in input data with a relative time
reference of when that change occurred.

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