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Reference Manual
00809-0200-4801, Rev BA
April 2007
Rosemount 3051S
3-14
Filtering The filtering feature changes the response time of the device to smooth
variations in output readings caused by rapid changes in input. Adjust the
filter time constant (in seconds) using the PV_FTIME parameter. Set the filter
time constant to zero to disable the filter feature.
Figure 3-3. Analog Input
PV_FTIME filtering Diagram.
Low Cutoff When the converted input value is below the limit specified by the LOW_CUT
parameter, and the Low Cutoff I/O option (IO_OPTS) is enabled (True), a
value of zero is used for the converted value (PV). This option is useful to
eliminate false readings when the differential pressure measurement is close
to zero, and it may also be useful with zero-based measurement devices such
as flowmeters.
NOTE
Low Cutoff is the only I/O option supported by the AI block. Set the I/O option
in Manual or Out of Service mode only.
PV_FTIME
63% of Change
OUT (mode in man)
OUT (mode in auto)
PV
Time (seconds)
FIELD_VAL