Emerson Rosemount 3490 Series Reference Manual page 79

Reference Manual
00809-0100-4841
When a flume is selected from this list, the control unit also populates parameters P400
and P401 (current output span), P530 (totalizer factor), and P531 (totalizer units of m
galx100).
Note
Rosemount 3491/3493:
P113, P115, and P116 are in the menus SETUP → [CONTROLLER] → INPUT CHANNEL →
Ch1 Profile, → Ch1 NLP Data, and Ch1 Post Scale (respectively).
Note
Rosemount 3492:
P113, P115, and P116 are in the menus SETUP → [CONTROLLER] → PV CALCULATION →
CHANNEL 1 → Ch1 Profile, → Ch1 NLP Data, and Ch1 Post Scale (respectively).
P123, P125, and P126 are in the menus SETUP → [CONTROLLER] → PV CALCULATION →
CHANNEL 2 → Ch2 Profile, → Ch2 NLP Data, and Ch2 Post Scale (respectively).
Set-up Kindsvater Shen (V-notch ISO1438) flow calculations
P113/P123 = "Kindsvater Shen"
This flow calculation requires just the angle of the V-notch to be entered in parameter
P115 (or P125) to calculate a flow value over the weir. The head level measurement needs
to be in units of meters and the resultant flow value is in cubic meters per second (m
Note
Flow calculations require the transmitter input channel(s) to be providing continuous level
measurements. Also, P200 (control unit PV units) must be changed from the default % to
the required flow measurement units.
When using the App Wizard, select V-Notch (ISO1438) at the prompt for a profile. The
App Wizard allows the selection of alternative flow units for the output result.
Related information
Optional change: transmitter input channel settings (advanced users)
Set-up exponential flow law calculations
P113/P123 = "Flow calculation"
Exponential laws are supported by selecting this profile option, and manually entering
values of k-factor, power, and mul into parameters P115 (or P125).
The output is derived from the input value using: Q = k × (mul × Input)
For example, consider an application with a rectangular weir and level measurements in ft.
When the flow rate (Q) is 2000 GPM, the gauged head (Input) is known to be 0.792 ft.
Terms mul is 1.000 and pwr is 1.5 for a rectangular weir.
Therefore, k is calculated as Q/(mul × Input)
Note
Flow calculations require the transmitter input channel(s) to be providing continuous level
measurements. Also, P200 (control unit PV units) must be changed.
Emerson.com/Rosemount
pwr 1.5
) = 2000/(1 × 0.792)
Getting started
January 2021
3
or
3
/s).
pwr
= 2837.5
79