Rockwell Automation Allen-Bradley 1769-IF4, Руководство пользователя

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Publication 1769-UM002B-EN-P - July 2005
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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 12-bit system has 4096 possible output states. It can therefore measure 1 part
in 4096.
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”