Rockwell Automation 1762-IR4 RTD/Resistance Input Module User Manual

Page 94

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Publication 1762-UM003A-EN-P - February 2003

4 Glossary

full-scale input. See the variation from the straight line due to linearity
error (exaggerated) in the example below.

LSB

Least significant bit. The LSB represents the smallest value within a
string of bits. For analog modules, 16-bit, two’s complement binary
codes are used in the I/O image. For analog inputs, the LSB is defined
as the rightmost bit of the 16-bit field (bit 0). The weight of the LSB
value is defined as the full-scale range divided by the resolution.

module scan time

same as module update time

module update time

The time required for the module to sample and convert the input
signals of all enabled input channels and make the resulting data
values available to the processor.

multiplexer

An switching system that allows several signals to share a common
A/D converter.

normal mode rejection

(differential mode rejection) A logarithmic measure, in dB, of a
device’s ability to reject noise signals between or among circuit signal
conductors. The measurement does not apply to noise signals
between the equipment grounding conductor or signal reference
structure and the signal conductors.

number of significant bits

The power of two that represents the total number of completely
different digital codes to which an analog signal can be converted or
from which it can be generated.

Ideal Transfer

Actual Transfer
Function

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