2600T Series Pressure transmitters |
OI/266/FF/ADD-EN Rev. B 49
The flow compensation functions have limits on the amount of compensation applied to the PV, to assure graceful degradation if an
auxiliary input is unstable. The internal limited value is
f
.
Equations
Algorythm type
Description
Function
Flow Compensation Linear
Used for density compensation of Volume flow
OUT= {f · PV · GAIN + BIAS
}
Where
f
= is limited
Flow Compensation Square Root
Usually:
– IN_1 is pressure – (t_1)
– IN_2 is temperature – (t_2)
– IN_3 is the compressibility factor Z – (t_3)
OUT= {f · PV · GAIN + BIAS
}
Where
f
= for Volumetric Flow is limited
For the calculation of the Volumetric Flow t_3 = Z
The compressibility factor Z can be set writing into the
IN_3 a constant value Z or can be calculated by a pre-
vious block linked in the IN_3.
OUT= {f · PV · GAIN + BIAS
}
Where
f
= for Volumetric Flow is limited
In case it would be necessary produce the Mass Flow,
the compressibility factor Z must be set as into the
IN_3 as
Flow Compensation Approximate
Both IN_1 and IN_2 would be connected to the same
temperature
NOTE:
– The Square Root of the third power can be achieved
connecting the input to IN and IN_1.
– The Square Root of the fifth power can be achieved
connecting the input to IN, IN_1, IN_3.
OUT= {f · PV · GAIN + BIAS
}
Where
f
= is limited
BTU Flow
– IN_1 is the inlet temperature
– IN_2 is the outlet temperature
OUT= {f · PV · GAIN + BIAS
}
Where
f = t_1 – t_2
is limited
Traditional Multiply Divide
OUT= {f · PV · GAIN + BIAS
}
Where
f = + t_3
is limited
Average
OUT=
·
GAIN + BIAS
f=
number of inputs used in computation
Traditional Summer
OUT= (PV + t_1 + t_2 + t_3) · GAIN + BIAS
Fourth Order Polynomial
All inputs except IN_LO (not used) are linked together
OUT= (PV + t_1
2
+ t_2
3
+ t_3
4
) · GAIN + BIAS
Simple HTG Compensated Level
– The PV is the tank base pressure
– IN_1 is the top pressure – (t_1)
– IN_2 is the density correction pressure – (t_2)
– GAIN is the height of the density tap
OUT=
·
GAIN + BIAS
Configuration hints
The minimum configuration for having the AR working and/or moving out from the OOS needs at least the following settings:
– Set ARITH_TYPE with a valid value. It must be different by 0 and in the range 1 – 9
– If the selected ARITH_TYPE is in the range between 1-5 (limited functions), the output limits COMP_HI_LIM > COMP_LO_LIM
– The BAL_TIME must be greater than the Block Execution Time
– When the ARITH_TYPE = 6 (Average) in case of no inputs available the output will be set to NaN (Not a Number)
– Set the GAIN with value different by 0
t_1
t_2
√
t_1
t_2 · t_3
√
t_1 · t_3
t_2
1
Z
√
t_1 · t_2 · t_3
2
PV – t_1
PV – t_2
t_1
t_2
PV + t_1 + t_2 + t_3
f
