Emerson Rosemount 3490 Series, Справочное руководство

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Essential parameters to program
Select a popular non-linear vessel shape
Use P113 (or P123) to select a non-linear vessel shape from the option list. The control unit
then automatically populates P115 (or P125) with data from the built-in library.
The volumetric contents calculations for these non-linear profiles require an input value
over the range 0.0 to 1.0. Parameter P114 (or P124) is therefore used to convert (scale)
the input signal to a value within the range 0.0 to 1.0 for the volume calculation.
Note
Rosemount 3491/3493:
P113, P114, and P115 are in the menus
SETUP
→
[CONTROLLER]
→
INPUT CHANNEL
→
Ch1 Profile,
→
Ch1 Pre scale, and Ch1 NLP Data (respectively)
→
.
Note
Rosemount 3492:
P113, P114, and P115 are in these menus:
SETUP
→
[CONTROLLER]
→
PV CALCULATION
→
CHANNEL 1
→
Ch1 Profile,
→
Ch1 Pre
scale, and Ch1 NLP Data (respectively) .
P123, P124, and P125 are in these menus:
SETUP
→
[CONTROLLER]
→
PV CALCULATION
→
CHANNEL 2
→
Ch2 Profile,
→
Ch2 Pre
scale, and Ch2 NLP Data (respectively) .
Setting P114 when a 4–20 mA level transmitter is connected
The 4–20 mA level transmitter should ideally provide a mA signal that is already scaled for
the full vessel height. P114 (or P124) can then be kept set at the default value of 1.0.
If the mA signal is not scaled for the full vessel height, P114 (or P124) must be
programmed with a value to convert (scale) the mA signal to be in the range 0.0 to 1.0. For
example, if the maximum current is below 20 mA for a full vessel, say 18 mA, set P114 = 16
(18 - 4) = 1.143
Setting P114 (or P124) when a HART level transmitter is connected
The maximum level measurement from the HART transmitter must be equal to the height
of the liquid when the vessel is full.
The level measurement, after any input offset has been applied, must be re-scaled to the
range 0.0 to 1.0 ready for input to the NLP calculation.
For example, if the level measurement range is 0.0 to 4.0, set P114 = (1.0/4.0) = 0.25
Getting started Reference Manual
January 2021 00809-0100-4841
74 Emerson.com/Rosemount