Emerson Rosemount 3051 CF Series, Reference Manual

Page: 42 / 146

Figure 2-14: Analog Input PV_FTIME Filtering Diagram
A. OUT (mode in man)
B. OUT (mode in auto)
C. PV
D. 63% of change
E. FIELD_VAL
F. PV_FTIME
G. Time (seconds)
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.
Process alarms
Process alarms are part of the process loop control strategy. They are configured in the
control host. Process alarm configuration is not included in the configuration menu tree.
See your control host documentation for information on configuration of process alarms.
Process Alarm detection is based on the OUT value. Configure the alarm limits of the
following standard alarms:
• High (HI_LIM)
• High high (HI_HI_LIM)
• Low (LO_LIM)
• Low low (LO_LO_LIM)
Configuration Reference Manual
July 2020 00809-0100-4774
42 Rosemount 3051