Glossary – Rockwell Automation 1746-NR4 SLC RTD/Resistance Input Module User Manual User Manual

Page 135

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135

Publication 1746-UM008B-EN-P - December 2006

Glossary

The following terms and abbreviations are specific to this product. For
a complete listing of Allen-Bradley terminology, refer to the
Allen-Bradley Industrial Automation Glossary, Publication Number
AG-7.1.

A/D

Refers to the analog-to-digital converter inherent to the
RTD/Resistance input module. The converter produces a digital value
whose magnitude is proportional to the instantaneous magnitude of
an analog input signal.

attenuation

The reduction in the magnitude of a signal as it passes through a
system.

channel

Refers to one of four small-signal analog input interfaces available on
the module’s terminal block. Each channel is configured for
connection to an RTD or potentiometer input device and has its own
diagnostic status word.

chassis

A hardware assembly that houses devices such as I/O modules,
adapter modules, processor modules, and power supplies.

common mode rejection ratio

The ratio of a device’s differential voltage gain to common mode
voltage gain, expressed in dB.

CMRR

20 Log

10 (V1/V2)

common mode voltage

A voltage signal induced in conductors with respect to ground
(0 potential).

configuration word

Contains the channel configuration information needed by the module
to configure and operate each channel. Information is written to the
configuration word through the logic supplied in your ladder
program.

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