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Thread: Value, Time-Stamp and status with allocations

  1. #1

    Default Value, Time-Stamp and status with allocations

    What exactly is being mapped when using an allocation?
    Generally an allocation can be used to transfer a variable value from PLC A to PLC B, even if this is a totally different brand.

    Normally, (if no trigger variable is used) the allocation is executed spontaneously. As soon as the source variable changes, the same value will be written to the target variable.

    With a trigger variable the allocation can be controlled. E.g. continiously when the triggervariable has the value "1" or at a rising edge of the trigger variable, the allocation is executed.

    In both cases, only the value from the source variable is being written to the target variable, not the status and the time-stamp. With a spontaneous allocation however, the difference in timestamp of the source and target variable is only a few milliseconds.

  2. #2
    Join Date

    Default Re: Value, Time-Stamp and status with allocations


    I might missunderstood this a little but, you said if you transfer from PLC to PLC through a Edge trigger  the Status and Timestand get lost.

    But what if you transfer from Internal variable to a PLC variable? 
    I saw at the Allocations help that the internal driver process the status and timestamp, does that mean that the internal driver would transfer to the PLC driver but the PLC driver would not copy them?
    Or the status and timestamp is not transferred just if the source variable is a PLC variable? 

    Hope you can help me understand this.


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