Endress+Hauser Liquistation CSF34 - Page 140

Operation Liquistation CSF34
140 Endress+Hauser
Calculated pH value
The pH value can be calculated from the measured values of two conductivity sensors
under certain conditions. Areas of application include power stations, steam generators
and boiler feedwater.
Menu/Setup/Additional functions/Mathematical functions/MF1 to 8/Mode = pH calculation from
conductivity
Function Options Info
Calculation Selection
• Off
• On
Factory setting
Off
On/off switch for the function
Method Selection
• NaOH
• NH3
• LiOH
Factory setting
NaOH
The calculation is performed on the basis of
Guideline VGB‐R‐450L of the Technical
Association of Large Power Plant Operators
(Verband der Großkesselbetreiber, (VGB)).
NaOH
pH = 11 + log {(κ
v
- 1/3 κ
h
)/273}
NH3
pH = 11 + log {(κ
v
- 1/3 κ
h
)/243}
LiOH
pH = 11 + log {(κ
v
- 1/3 κ
h
)/228}
κ
v
... Inlet ... direct conductivity
κ
h
... Outlet ... acid conductivity
Inlet The options depend on the
sensors connected
Inlet
Sensor upstream from the cation exchanger,
"direct conductivity"
Outlet
Sensor downstream from the cation exchanger,
"acid conductivity"
Selection of the measured value is obsolete as it
must always be Conductivity.
Measured value
Outlet
Measured value
Calculated pH Read only View this value in a user-defined measuring
screen or output the value via the current output.
Mathematical function
assignment view
Overview of the configured functions
Formula (optional, with activation code)
With the formula editor, it is possible to calculate a new value from a maximum of 3
measured values. A wide range of mathematical and logical (Boolean) operations are
available for this purpose.
The Liquiline firmware offers you a powerful mathematics tool with the formula
editor. You are responsible for the feasibility of your formula, and therefore for the
feasibility of the result.
Symbol Operation Type of operands Type of result Example
+ Addition Numerical Numerical A+2
- Subtraction Numerical Numerical 100-B
* Multiplication Numerical Numerical A*C
/ Division Numerical Numerical B/100
^ Power Numerical Numerical A^5
² Square Numerical Numerical A²
³ Cube Numerical Numerical B³