Echelon i.LON 100 e2 Internet Server - Manual (Page 148)

i. LON 100 Internet Server Programmer’s Reference 9-11
Identifier Value Assigned To The Output Data Point
FN_NUL Value not available.
9.2.1.2.2 Comparison Functions
Table 47 lists and describes the comparison functions you can use to fill in the
property. You must reference each function by the identifier listed in
the table.
Table 47 Comparison Function Identifiers
Identifier Description
FN_GT Greater than. Returns True if the value of the input data point is greater than that
of the compare data point (or the value assigned to the
property, if it is defined).
FN_LT Less than. Returns True if the value of the input data point is less than that of the
compare data point (or the value assigned to the property,
if it is defined).
FN_GE Greater than or equal to. Returns True if the value of the input data point is
greater than or equal to that of the compare data point (or the value assigned to
the property, if it is defined).
FN_LE Less than or equal to. Returns True if the value of the input data point is less
than or equal to that of the compare data point (or the value assigned to the
property, if it is defined).
FN_EQ Equal. Returns True if the value of the input data point is equal to that of the
compare data point (or the value assigned to the property,
if it is defined).
FN_NE Not equal. Returns True if the value of the input data point is not equal to that of
the compare data point (or the value assigned to the
property, if it is defined).
FN_NUL Value not available. Returns True if the value of the input data point is not
available.
9.2.1.2.3 FN_AND Example
: FN_AND
: FN_GT
In this example, there are four input data points and one compare data point, all of the type
SNVT_count. There is one output data point, of the type SNVT_Switch.
Because the output function is FN_AND, the comparisons made with all the input data
points must return True in order for the output data point to be set to True. The comparison
function is FN_GT, so the value of each input data point must be greater than the value of
the compare data point, or the value if it is defined, for this to
happen. If the property is defined, then the value of the compare data
point is not used in the comparison.
Table 48 lists several case scenarios that show when these functions might would evaluate to
True.