Rockwell Automation 1769-OF4VI Compact I/O Isolated Analog Modules - Manual (Page 120)

Publication 1769-UM014B-EN-P - May 2010
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configuration word – Contains the channel configuration information
needed by the module to configure and operate each channel.
D/A Converter– Refers to the digital to analog converter inherent to the
output module. The converter produces an analog dc voltage or current signal
whose instantaneous magnitude is proportional to the magnitude of a digital
value.
dB – (decibel) A logarithmic measure of the ratio of two signal levels.
data echo – The analog value currently being converted by the D/A converter
and shown in words 2 and 3 of the output module’s input data file. Under
normal operating conditions, the data echo value is the same value that is being
sent from the bus master to the output module.
data word – A 16-bit integer that represents the value of the analog input or
output 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).
differential operation – The difference in voltage between a channel’s
positive terminal and negative terminal.
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.
filter – A device that passes a signal or range of signals and eliminates all
others.
filter frequency – (-3 dB frequency) The user-selectable frequency.
full scale – The magnitude of voltage or current over which normal operation
is permitted.
full scale error – (gain error) The difference in slope between the actual and
ideal analog transfer functions.
full scale range – (FSR) The difference between the maximum and minimum
specified analog input values.
hold last state – A configuration selection that instructs the module to keep
the outputs at the last converted value prior to the condition that caused the
control system to enter the fault or program mode.
input image – The input from the module to the controller. The input image
contains the module data words and status bits.