CX_TIMED_TRIGGER - Signal Class

CX_TIMED_TRIGGER

Class hierarchy

Description:

An object of this class can be used to manage actions that are not to be triggered immediately, but at one or more specific times. The action consists of two steps (each optional) and is triggered at the time set with SetActionTerm:

1. A start signal defined with SetMsg or SetStartEndMsg is transmitted
2. An end signal defined with SetEndMsg or SetStartEndMsg is sent

With SetCycles, the maximum number of transmitted signals can also be fixed. If both start message and end message are defined, the start message is always sent before the end message.
The sent messages are always called up on the stack with the same parameters:

Application examples:

1. Reproduction of an alarm clock
2. Triggering a cyclic backup
3. At 12.00 noon changeover from "coming" to "going" at a flexitime terminal

Code example:

Msg(COUNT_DOWN)
Var(timedTrigger, dateTime)
CreateTransObject(CX_TIMED_TRIGGER) -> timedTrigger

// Define and set moments for sending a message
CreateTransObject(CX_DATETIME) -> dateTime
CreateTransObject(CX_PERIODIC_SPAN_TIME) dateTime Link(time)
"1 min" dateTime Put(time.frequency)
1 dateTime Put(time.validEnum) // 0 = " from/until", 1 = "from", 2 = "until", 3 = "unlimited"
dateTime timedTrigger Call(SetActionTerm)

// Set message to be sent
(COUNT_DOWN) timedTrigger Call(SetMsg)

// Activate trigger
timedTrigger Call(Activate)

Window(TestWin, 10, 50, 200,  100, "Time trigger")
[ INITIALIZE:  10 timedTrigger Call(SetCycles)
                                // .... further statements

    COUNT_DOWN: -> triggerIndex // index of signals sent
                -> maxCycles    // max. number of cycles set by SetCycles
                -> timedTrigger // the timed trigger object, which has send this message 
                                // .... further statements
]
{}

The TimeTrigger runs in a separate thread. This means that it sends messages even if the main thread is busy and cannot process the messages at all. The messages are then queued until the main thread is free again and are then received. In this way, the same message from the TimeTrigger can be received relatively often within a short time. The following example code only takes into account the last message of the collected ones and ignores the others.

// create timed trigger
CreateTransObject(CX_TIMED_TRIGGER) -> timedTrigger
(TIME_TRIGGER_MESSAGE) timedTrigger Call(SetMsg)
CreateTransObject(CX_PERIODIC_SPAN_TIME, KEEP) -> tmpTime

// Set frequency in seconds
5s tmpTime Put(frequency)  // fire once every 5 seconds
3 tmpTime Put(validEnum)
tmpTime timedTrigger Call(SetActionTerm)

// Activate trigger
timedTrigger Call(Activate)

// Handling duplicate messages in the trigger message
TIME_TRIGGER_MESSAGE: Integer -> tmpIndex DropAll
                      // only execute the last message if there are more than one in the pipe
                      timedTrigger Call(TimesTriggered) tmpIndex > if return