Rockwell Automation 1762-IR4 RTD/Resistance Input Module - Manual (Page 92)

Publication 1762-UM003A-EN-P - February 2003
2 Glossary
common mode voltage range
The largest voltage difference allowed between either the positive or
negative terminal and analog common during normal differential
operation.
configuration word
Word containing the channel configuration information needed by the
module to configure and operate each channel.
cut-off frequency
The frequency at which the input signal is attenuated 3 dB by a digital
filter. Frequency components of the input signal that are below the
cut-off frequency are passed with under 3 dB of attenuation for
low-pass filters.
data word
A 16-bit integer that represents the value of the input channel. The
channel data word is valid only when the channel is enabled and
there are no channel errors. When the channel is disabled the channel
data word is cleared (0).
dB (decibel)
A logarithmic measure of the ratio of two signal levels.
digital filter
A low-pass filter incorporated into the A/D converter. The digital filter
provides very steep roll-off above it’s cut-off frequency, which
provides high frequency noise rejection.
effective resolution
The number of bits in a channel configuration word that do not vary
due to noise.
excitation current
A user-selectable current that the module sends through the input
device to produce an analog signal that the module can process and
convert to temperature (RTD) or resistance in ohms (resistance
device).