Two Polynomial Functions Of 2; Nd Order; Set The Transfer Function On The Transmitter; Set The Transfer Function On The Transmitter By Digital Lcd Integral Display - ABB 2600T Pressure Transmitter Series User Manual

364xS User's Manual
Spherical tank
The following polynomium gives the area of the circular
section in relation to the height of the liquid in the vessel (h):
2 3
Output = 3 h - 2h
Volume = Output • (d/1.2407)
where: d = sphere diameter
Partial level measurement
Two methods can be used:
1) Plot the changes in volume in relation to the level changes
and using a mathematical method, find the relevant
polynomium;
2) Use the above polynomium coefficients and calibrate the
transmitter range to cover the full diameter of the vessel or
tank: the changes in volume for the h changes between h
and h will be correct. Of course the transmitter will
max
transmit, when the level is ≤h
: the same apply for level ≥h
to h
0

Two Polynomial functions of 2

The Analog Output transfer function can also be
defined as a two
nd
polynomials are of 2
polynomial functions are used:
Output = A + A x + A x
0 1 2
Output = B + B x + B x
0 1 2
Ax and Bx terms of the polynomials have to be
calculated according to the shape of the vessel.
A PC based software tool is available for polynomial
coefficients definition.

Set the Transfer function on the transmitter

Set the Transfer function on the transmitter by Digital LCD Integral Display

Navigate the Digital LCD Integral Display menu, select
Transfer Function in use will be available. To modify select
(see the following table) with the up and down keys and confirm with OK.
Linear
Square Root
3/2
5/2
Polynomial
Double Poly
Bidirectional Flow
Digital LCD Integral Display Keys sequence to set the Transfer Function: 2 – 6 – 1 – Edit
3
, the volume corresponding
0
.
max
nd
order
polynomial function.
order. So two different
2
if x ≤ k
2
if x > k
Output = x
1/2
Output = x
3/2
Output = x
5/2
Output = x
Output = A + A x + A
0 1
Output = B + B x + B
0 1
Output = C + C x + C
0 1
Output = ½ + ½ sign (x) x
0
1
Both
K
0
Device Config > Transfer Function
Edit then scroll the desired Transfer Function
2 3 4
x + A x + A x + A
2 3 4
2
if x ≤ k
x
2
2
x if x > k
2
1/2
> Type, and the
5
x
5
Configuration
35