Rockwell Automation 1769-IF4XOF2 Compact 8-Bit Low Resolution Analog I/O Combination Module - Manual (Page 96)

Publication 1769-UM008A-EN-P - November 2001
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overall accuracy – The worst-case deviation of the output voltage or
current from the ideal over the full output range is the overall
accuracy. For inputs, the worst-case deviation of the digital
representation of the input signal from the ideal over the full input
range is the overall accuracy. this is expressed in percent of full scale.
Gain error, offset error, and linearity error all contribute to input and
output channel accuracy.
output accuracy – The difference between the actual analog output
value and what is expected, when a given digital code is applied to
the d/a converter. Expressed as a ± percent of full scale. The error will
include gain, offset and drift elements, and is defined at 25°C, and also
over the full operating temperature range (0 to 60°C).
output image – The output from the controller to the output module.
The output image contains the analog output data.
analog output module – An I/O module that contains circuits that
output an analog dc voltage or current signal proportional to a digital
value transferred to the module from the processor.
repeatability – The closeness of agreement among repeated
measurements of the same variable under the same conditions.
resolution – The smallest detectable change in a measurement,
typically expressed in engineering units (e.g. 1 mV) or as a number of
bits. For example a 8-bit system has 256 possible output states. It can
therefore measure 1 part in 256.
status word – Contains status information about the channel’s current
configuration and operational state. You can use this information in
your ladder program to determine whether the channel data word is
valid.
step response time – For inputs, this is the time required for the
channel data word signal to reach a specified percentage of its
expected final value, given a large step change in the input signal.
update time – see “module update time”