Rockwell Automation Publication 1444-UM001D-EN-P - June 2018
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Operate the Module
Chapter 10
Full Scale Range
The module does not apply amplifiers or attenuator to the analog signals to
“scale” signals to some “full scale” value. Rather the module relies on its
precision 24 bit A/D and further digital processing to accommodate
measurement requirements. The 1444 does not provide a “full scale range” in
the same manner as older instruments.
When considering resolution and accuracy, rather than providing values
referenced to a possible “full scale range”, the following reference values to a
“typical range or alarm limit”, which vary with the selected engineering units
and application.
Measurement Resolution
The 24 bit A/D has a theoretical resolution of 3 μV. However, for practical
purposes, an input signal of 0.5 mV peak-to-peak is considered more
representative of real world applications, and as a more realistic minimum
resolution. Based on this assessment the following table presents typical
resolutions, in Engineering Units, and as a percent of a typical range or alarm
limit for various measurement types.
Table 75 - Typical Measurement Resolution
Measurement
Type
Sensitivity
Typical Range or Alarm Limit
EU (at 0.5 mV Input)
Resolution (%)
Acceleration
100 mV/g
40 g RMS
0.0018 g RMS
0.0045
Velocity
(integrated)
100 mV/g
25 mm/s RMS
0.0018 mm/s RMS
0.0072
100 mV/g
1 ips RMS
0.000007 ips RMS
0.0071
Velocity
4 mV/mm/s
25 mm/s RMS
0.0442 mm/s RMS
0.18
100 mV/ips
1 ips RMS
0.0017 ips RMS
0.18
Displacement
8 mV/micron
125 micron pk-pk
0.0625 micron pk-pk
0.05
200 mV/mil
5 mil pk-pk
0.0025 mil pk-pk
0.05
Thrust (DC)
8 mV/micron
2 mm
0.0625 micron
0.003
200 mV/mil
80 mil
0.0025 mil
0.003
Dynamic Pressure
100 mV/psi
2 psi RMS
0.0018 psi RMS
0.09