Specifications

Chapter 1 - AsconACLib
27
1-3-20 DEW_POINT
FB Prototype DEW_POINT
Input parameters
Output parameters
Description This function block performs the Dew Point calculation by using temperature
(TEMP) and relative humidity (HR) valid values. A “valid value” means TEMP input
value is inside the range defined by LOW_LIM HIGH_LIM parameters and HR
value in between 0.0 100.0 %, otherwise they will be not computed. The function
block returns a temperature value accordingly to the SEL_C_F selection.
Default Values Table
Reference Table
Label Type Description Range
ENABLE BOOL Command to enable average calculation
SEL_C_F BOOL
Temperature engineering unit [°C or °F]
TEMP REAL Temperature input value [in °C or °F]
LOW_LIM...
HIGH_LIM
HR REAL Relative Humidity input value [%] 0.0... 100.0
HIGH_LIM REAL
High limit for the AI channel value [e.u.]
-3.4E
-38
... 3.4E
+38
LOW_LIM REAL Low limit for the AI channel value [e.u.]
-3.4E
-38
... 3.4E
+38
Label Type Description Description
ERROR BOOL Error status
ERR_CODE DWORD Error code [bit mask]
6#00 00 00 00...
16#FF FF FF FF
DP_VALUE REAL Dew Point calculated value [°C or F] LOW_LIM... HIGH_LIM
ENABLE
SEL_C_F
TEMP
HR
HIGH_LIM
LOW_LIM
BOOL
BOOL
REAL
REAL
REAL
REAL
¡
¡
¡
¡
¡
¡
BOOL
DWORD
REAL
ERROR
ERR_CODE
DP_VALUE
¡
¡
¡
Input Default Value
ENABLE FALSE
SEL_C_F FALSE = °C Degrees
TEMP 25.0
HR 50.0
HIGH_LIM 999.0
LOW_LIM -99.0
Output Description
ERR_CODE.0 Temperature value lower than the admitted value
ERR_CODE.1 Temperature value higher than the admitted value
ERR_CODE.2 Relative Humidity value lower than the admitted value
ERR_CODE.3 Relative Humidity value higher than the admitted value