Allen-Bradley MicroLogix 1200 User Manual page 136

Glossary G-2
Publication 1762-UM002A-EN-P - July 2002
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.
filter – A device that passes a signal or range of signals and eliminates
all others.
filter frequency – The user-selectable frequency for a digital filter.
full-scale – The magnitude of input over which normal operation is
permitted.
full-scale range – The difference between the maximum and
minimum specified analog input values for a device.
gain drift – Change in full-scale transition voltage measured over the
operating temperature range of the module.
input data scaling – Data scaling that depends on the data format
selected for a channel configuration word. Scaling is selected to fit the
temperature or voltage resolution for your application.
input image – The input from the module to the controller. The input
image contains the module data words and status bits.
linearity error – Any deviation of the converted input or actual
output from a straight line of values representing the ideal analog
input. An analog input is composed of a series of input values
corresponding to digital codes. For an ideal analog input, the values
lie in a straight line spaced by inputs corresponding to 1 LSB. Linearity