SMC Networks EliteView 6.20 - Manual (Page 91)

D
EFINING
F
ILTER
F
ORMULAS
7-7
Defining Filter Formulas
Filters may be defined for any log process. A filter sets the conditions that determine if data received by the Log
Manager will be saved into the log database. A filter is defined in the Filter field of the Log Information dialog box
(i.e., the dialog box opened when you create or edit a log process). If no filter is defined, then all the data received
is automatically logged.
Filter Formula
The filter formula uses Backus-Naur Form (BNF) as follows:
Filter::= SimpleExpression|
ComplexExpression|
-- Nothing
SimpleExpression::=Variable rel_op Value
Variable::= "VALUE"| --Value of the data
"DATE"| --Date the data arrives
"TIME"| --Time the data arrives
rel_op::= ">"| --Greater than
"<"| --Less than
">="| --Greater than or Equal to
"<="| --Less than or Equal to
"=="| --Equal
"!="| --Unequal
Value::=| --Number represented in decimal digits, within the range
of a 4-byte unsigned integer.
| --Eight digits representing a date
.
--Eight digits representing a time, in 24 hour format
ComplexExpression::=
"(" SimpleExpression ")" |
"(" ComplexExpression ")"|
ComplexExpression logic_op ComplexExpression
logic_op::="AND"|"OR"