This demo describes how to receive ADS notifications in a TwinCAT C++ module.

For this the solution contains 2 modules

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A C++ module, which registers for retrieving ADS notifications of a variable.

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For easy understanding: A PLC program, which provides a variable “MAIN.PlcVar”.
If its value is changes, an ads notification will be sent to the C++ module.

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The C++ module makes use of the logging capabilities – so for understanding the code, please simply start the sample and look at the Output / Error log if you change the value of PLC module’s “Main.PlcVar”.

Within the module transition PREOP->SAFEOP ( “SetObjStatePS”) the address is prepared. The “CycleUpdate” method contains a simple state machine, sending the required ADS commands. Corresponding Methods indicate the received confirmations.

The inherited and overloaded method “AdsDeviceNotificationInd” will be called upon arrival of a notification.

During shutdown ADS messages for deregistration are sent out in transition (“SetObjStateOS”) and the module waits for arrival of confirmations until a timeout occurs.