Echelon LonPoint Application and Plug-In - Manual (Page 156)

11-10 Schedule Keeper Utility
The Schedule Constraint Language
By default the units used in these equations are the ones native to the relevant
network variable types. See Converting to US Units, later in this chapter, for
information on using non-SI units.
The following notation will be used in the examples and grammar:
Operands
e is the time at which the event e occurs and is in the range 0:00 < e< 23:59
For example, if e is the event MorningWarmup ON @ 6:00 AM, then e is 6:00.
t is a time variable in the range 0:00 < t < 23:59. The time separator character is
specific to the locale of the PC (e.g., “:” for US users and “.” for French).
Operators
Relational Operators
t
1
= t
2
t
1
must be the same time as t
2
t
1
!= t
2
t
1
must not be the same time as t
2
t
1
< t
2
t
1
must occur before t
2
t
1
<= t
2
t
1
may not occur after t
2
t
1
> t
2
t
1
must occur after t
2
t
1
>= t
2
t
2
may not occur after t
1
Arithmetic Operators
t
1
+ t
1
The sum of t
1
and t
2
. If this sum is greater than 24:00,
24:00 will be subtracted from the result.
Boolean Operators
exp
1
& exp
1
If exp
1
and exp
1
are both true, the expression will
evaluate as true. If either exp
1
or exp
1
are false, the
expression will evaluate as false.
exp
1
| exp
1
If either exp
1
or exp
1
are true, the expression will evaluate
as true. If both exp
1
and exp
1
are false, the expression will
evaluate as false.
Existence Expression
e
1
e
1
must exist in all Schedules (the existence expression
may not be combined with any other construct in a
Schedule Constraint Equation).
Examples:
Example 1:
e
1
< 6:00 event e
1
must happen before 6am
e
1
+0:10 <= e
2
event e
1
must happen at least 10 minutes before event e
2