IM 01C25R01-01E
2-8
2. About Multivariable Transmitter
Method 2. Calculating the Kfactor by means of
the flow condition.
Flow conditions include; DP, SP, SPb, T, Tb, and
TempK1
(1) Selection of the flow equation
Select a desired operational expression according to
the fluid type and the flow unit category shown in
Table 2.1.
(2) Confirming the units
The unit to be used in the flow calculation is as
following;
Static Pressure : kPa abs
Temperature : K
Regardless of the actual setting of the unit for these
items in the transmitter, the above units are used for
calculation.
The flow and the differential pressure are calculated
using the unit setting in the transmitter.
(3) Preparation of parameters for calculation
All parameters use the units which are shown at
(2).
(4) Calculation of the Kfactor
Calculate the Kfactor using the parameters prepared
at (3) and flow expression selected at (1).
(5) Downloading flow parameter to transmitter.
Input Kfactor, Tb, SPb, and TempK1(liquid) to the
transmitter by a communication tool or EJXMVTool.
IMPORTANT
If either the setting of flow unit or differential
pressure unit is changed, Kfactor must be
recalculated.
Example: Kfactor Calculation
Table 2.9 Flow Condition of Example
T0209E.EPS
Qm
∆
p
Tb
SPb
T
SP
Symbol
3011.76 (lb/h)
201.0935 inH2O@68degF
273.15K
101.325 kPa abs
293.15K
500 kPa abs
Value
Differential pressure
Reference temperature unit: K
Reference static pressure unit: kPa abs
Temperature unit: K
Static pressure unit: kPa abs
Description
Kfactor = Qm(lb/h) /
∆
p
(Tb / T)
(SP / SPb)
= 3011.76 / 201.0935
(273.15 / 293.15)
(500 / 101.325)
= 99.0464
Table 2.10 For HART Communicator (Function : Basic Flow Calc)
T0210E.EPS
Kfactor
SPb
Tb
TempK1
Symbol
Flow Calc Fixed
Ref SP
Ref Temp
Temp K1
HART Parameter name
Calcuration fixation value of flow
Reference static pressure
Reference pressure
The first in temperature
correction coefficient for liquid
For volume flow: set 0.
Item
1, 4, 8, 3
1, 4, 8, 4
1, 4, 8, 5
1, 4, 8, 6
Fast key sequences
