Special Functions; Transfer Functions; Transfer Functions Description; Linear - ABB 2600T Pressure Transmitter Series User Manual

364xS User's Manual

Special functions

The transmitter has some functions to support the user in case of applications that require advance output
configuration.

Transfer functions

The 2600T Pressure Transmitter Series provides a selection of output functions, as follows:

Linear

for differential, gauge and absolute
pressure or level measurements
Sq. Root (x) for flow measurements using restriction
type primary element, like orifice plate,
integral orifice, Venturi or Dall tube and
similar.
Sq. Root (x3) for open channel flow measurements
using rectangular or trapezoidal weir
Sq. Root (x5) for open channel flow measurements
using V-notch (triangular) weir.
Polynomial for input linearization using a 5th-order
polynomial function for input
linearization using 2 polynomial
functions of 2nd order
Costant current for loop or associated equipment test.
These output functions can be activated using a Configuration Tool (CoMeter, Digital LCD Integral Display,
Hand Held Communicator and PC).
The transfer function can be applied to the analog signal 4 to 20 mA or to the indication (in engineering units)
on the CoMeter with the 695 Field Indicator and/or to the Digital LCD Integral Display.

Transfer functions description

Linear
Using this function, the relationship between the input (measured value), expressed in % of the calibrated
span and the output is linear (i.e.: at 0% input, corresponds 0% output - 4mA - at 50% input corresponds
50% output - 12mA - and at 100% input corresponds 100% output - 20mA).

Square roots

Using the Square Root function, the output (in % of the
span) is proportional to the square root of the input
signal in percentage of the calibrated span (i.e.: the
instrument gives an analog output proportional to the
rate of flow). The possibility to have the full Square
Root function is given.
Note: x and output are in the range 0 to 1 (0% to 100%)
25
20
15
10
5
0
0 1 2 3
%
32
4 5 6
Configuration