Emerson Rosemount 3490 Series Reference Manual page 68

Getting started
January 2021
Applying the optional scaling and profiling to the selected source
If volumetric or flow values are in the selected HART variable, set parameter P113 to
Scaled.
Use parameter P114 to convert (scale) the value into units that match the selected display
units (P200, P201, P202 or P203, as applicable in SETUP → CONTROLLER → DISPLAY).
If level values are in the selected HART variable, parameter P113 can be set to Scaled if
wanting just level measurement, and then use parameter P114 as described above. By
selecting profile calculation using P113, a level value can be used to calculate a volumetric
or open channel flow rate. The programming (configuring) required for this can be found
in Volumetric contents and flow measurement applications (advanced
Note
P113 and P114 are in the sub-menus/Ch1 Profile and/Ch1 Pre scale at:
SETUP → CONTROLLER → INPUT CHANNEL (on 3491/3) or SETUP → CONTROLLER → PV
CALCULATION → CHANNEL 1 (on 3492)
Applying an optional low-cut-off action
The channel 1 output result in D851 can be forced to zero when it falls below a positive
threshold, which is a percentage of the maximum flow. Enter the percentage in P117. By
default, the setting is "None" to switch off this optional check.
This feature is particularly useful in an open channel flow application where a small
standing or remaining liquid level in the channel would cause continued totalizing of flow
when no actual flow exists. As a guide, set P117 to a positive value of 2% of maximum flow
to overcome this problem.
Note
P117 is in this menu:
SETUP → CONTROLLER → INPUT CHANNEL → Ch1 Low Cut-off (on 3491/3) or SETUP →
CONTROLLER → PV CALCULATION → CHANNEL 1 → Ch1 Low Cut-off (on 3492)
Applying optional damping to the control unit P
P210 is for applying damping to smooth out big steps in calculated values in D851.
Note
P210 is in the menu SETUP → CONTROLLER → OUTPUT → PV DAMPING → MCU PV
DAMPING.
D851 is in the menu MONITOR → DIAGNOSTICS → CHANNELS → Ch1 Output.
4.4.8 Programming Channel 2 for a HART input (Rosemount
3492 and advanced users only)
Procedure
Set Input Channel 2 to receive HART digital data from a transmitter.
a) Navigate to SETUP → [CONTROLLER] → INPUT CHANNEL → CHANNEL 2 → Ch2 I/P
68
Source for the Ch2 I/P Source parameter P121.
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