4.5. *EVENT MACHINE
4.5.4
Signals
As described in the previous section, the
event machine
takes actions
whenever a user defined trigger goes off. This trigger is configured by
the user with the logical combination of situations. A situation makes
reference to the unit’s state which is in fact represented by
signals
and their state.
e-track
TM
’s
signals are of boolean nature, meaning
that they can only take one of two possible values:
true
or
false
.
Signals
and the logical operators
AND
,
OR
,
NOT
are used to create
logical equations to form events’ triggers.
By using the
SS
TAIP message a signal’s state can be consulted,
and depending on the signal’s type, this command can be used also
to change the signal’s state.
Signals’
names always have three characters.
Note:
The available signals for
e-track
TM
’s
are presented in the next table.
73
